ISSN 2185-159X

erd

International Journal ofEnvironmental and Rural Development

Volume 13 Number 1

June 2022

International Society of Environmental and Rural Development

IJERD – International Journal of Environmental and Rural Development

erdInternational Journal ofEnvironmental and Rural Development
Official Journal of the International Society of Environmental and Rural Development(Accessible from J-Stage, EBSCO, Google Scholar, CABI International, etc.)

Aims and Scope:
The International Journal of Environmental and Rural Development, IJERD, is an interdisciplinary journal
concerning environmental and rural development research in the education for sustainable development, ESD.
The IJERD is devoted to publishing peer-reviewed research article, review article and technical report in thefields of environmental and rural development, such as education for sustainable rural development, ruraldevelopment, environmental management or agricultural systems. Every article or report in IJERD must be
accepted by at least 2 reviewers and an editorial member.
The aims of IJERD are to publish the latest research development and achievements, to strengthen
education systems, to promote cooperation in environmental and rural development and to contribute to theprogress in sustainable development. The editorial board of this journal covers a variety of scientificdisciplines.

Thematic Areas:
The following areas are envisioned in IJERD.
Education for Sustainable Rural Development:
Environmental Education, Food and Agricultural Education, Participatory Approach, Capacity Building,Community Empowerment, Agricultural Extension, etc.
Rural Development:
Marketing, Partnership, Value Added Product, Community Development, Access to Technology,
Cultural Preservation, etc.
Environmental Management:
Bio-Diversity, Soil Degradation and Land Conservation, Water Quality Conservation, Deforestation andSustainable Forest Management, Environmental Management, etc.
Agricultural Systems:
Organic Farming, Conservation Tillage, Mechanization, Irrigation and Drainage, Nutrient and Pest
Management, Cattle Breeding, Agro-Forestry, Indigenous Technology, etc.
Infrastructural Systems:
Water Resource Development, Land Reclamation, Road Construction, etc.

Editorial Board:
Editor in Chief:
Prof. Dr. Machito Mihara, Tokyo University of Agriculture, Japan /Institute of Environmental Rehabilitation and Conservation, Japan
Managing Editors:
Dr. Narong Touch, Tokyo University of Agriculture, Japan
Dr. Shinobu Terauchi, Institute of Environmental Rehabilitation and Conservation, Japan
Dr. Jeeranuch Sakkhamduang, Institute of Environmental Rehabilitation and Conservation,
Southeast Asia Office / Association of Environmental and Rural Development, Thailand
Editorial Advisory Board:
Prof. Dr. Mom Seng, Royal University of Agriculture, Cambodia
Dr. Insa Kuhling, University of Applied Sciences, Germany
Dr. Carlos Onan Tovar Mendoza, Honduras Embassy in Japan, HondurasProf. Dr. Noureddin Driouech, Mediterranean Agronomic Institute of Bari, Italy
Prof. Dr. Kiichiro Hayashi, Nagoya University, Japan
Prof. Dr. Kingshuk Roy, Nihon University, Japan
Dr. Yuri Yamazaki, Tokyo University of Agriculture, Japan
Prof. Dr. Merites M. Buot, University of the Philippines Los Baños, Laguna, Philippines /UP Open University, Philippines
Prof. Dr. Salvador Catello, University of the Philippines, Philippines
Prof. Tomas Reyes, Jr. Bohol Island State University, Philippines

IJERD – International Journal of Environmental and Rural Development

Dr. Julian Torillo, Jr. Bohol Island State University, Philippines
Dr. Venkatachalam Anbumozhi, International Centre for Trade and Sustainable Development,
Switzerland
Dr. Anchasa Pramuanjaroenkij, Kasetsart University, Thailand
Prof. Dr. Rajendra P. Shrestha, Asian Institute of Technology, Thailand
Dr. Somsak Srisontisuk, Khon Kaen University, Thailand
Dr. Vidhaya Trelo-Ges, Khon Kaen University, Thailand
Prof. Dr. Vo Quang Minh, Cantho University, Vietnam

Editorial Section in ISERD Secretariat:
Research Center, Institute of Environmental Rehabilitation and Conservation (ERECON)
2987-1 Onoji Machida-shi, Tokyo 195-0064, Japan
Tel/Fax: +81-42736-8972
E-mail: iserd.secretariat@gmail.com
Webpage: www.iserd.net
Collaborated with

Association of Environmental and Rural Development (AERD)
93/64 Moo.3, Sinsab Village 2, Bungyeetho Sub-District, Thanyaburi District,Pathum Thani 12130, Thailand
Tel/Fax: +66-2957-8064
E-mail: iserd.secretariat@gmail.com
Webpage: www.iserd.net

Publisher of International Journal of Environmental and Rural Development:
Institute of Environmental Rehabilitation and Conservation (ERECON)
2987-1 Onoji Machida-shi, Tokyo 195-0064, Japan
Tel/Fax: +81-42736-8972
E-mail: hq-erecon@nifty.com
Webpage: www.erecon.jp

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Contents
Interactions among Soil Physical, Chemical and Biological Properties under Different Farming
Systems
Marisol Terashima and Machito Mihara

1

Farmers’ Organic and Inorganic Fertilizers Application and its Effects on Rice Productivity in Prey
Chhor District, Kampong Cham Province
Muy Leang Kim and Machito Mihara

7

Shedding Light on the Gender Gap in Cambodia’s Agriculture Sector - A Case of Agricultural
Cooperation in Kampong Cham Province
Mari Arimitsu, Shinobu Yamada, Kumiko Kawabe andMachito Mihara

14

The Influence of Agricultural Production Information on the Agricultural Management Scale in Rural
Areas of Cambodia
Shinobu Yamada, Mari Arimitsu, Machito Mihara andKumiko Kawabe

21

Moisture Content Prediction of Dried Young Papaya during Drying and Water Absorption
Sokly Sorm, Yoshiki Muramatsu, Masanori Hashiguchi,
Dahai Mi, Eiichiro Sakaguchi and Shotaro Kawakami

26

Estimates of Factor Shares for Rice Production in Japan for the Period of 1922-1944
Mitsuhiro Terauchi and Shinobu Yamada

34

Perspective on Urban and Peri-Urban Agriculture in Cambodia’s Capital: Phnom Penh
Ches Sophy, Eiji Yamaji and Thol Dina

40

The Dynamics of Social Interactions of Children Playing around Rural Rivers in Japan
Masayuki Nitta, Yoshiki Kuwabara and Masahiro Nakajima

46

Income Generation and Expenditure of Organic Rice Farming Households: Case Study of Preah Vihear
Province, Cambodia
Chanmony Sok, Tomohiro Uchiyama and Nina N. Shimoguchi

56

Economic Assessment of Tea Smallholder Farmers under Contract Farming in Rungwe District,Tanzania.
Issa Abrahaman Kachenje, Nina N. Shimoguchi,
Katsumori Hatanaka and Ramadhona Saville62

Performance Assessment of Simple Covered Lagoon Digester in Large-scale Pig Farm in Cambodia
Chan Makara Mean, Lyhour Hin, Lytour Lor, Dyna Theng,
Makara Lay and Bart Frederiks

68

Migration Characteristics of Communities in the Forestlands in Ifugao, Philippines
Carmelito C. Valdez and Gemma B. Dumansi

75

Discussion about A Model in Operation and Accumulation of Joint-Use Fund Management by Rice
Farmer-groups
Yuki Toyama, Asres Elias, Kumi Yasunobu andPanatda Utaranakorn

81

Product and Market Diversification Trends: The Case of Horticulture Exports in Kenya
Jane Githiga, Asres Elias and Kumi Yasunobu

88

Impact Assessment of System of Rice Intensification Adoption - Case from Madagascar Masato Kishimoto, Eiji Yamaji and Takeshi Sakurai

95i

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Effects of Lead and Other Metals from Historical Smelting on Sustainable Fruit and Vegetable
Cultivation
Barry Noller and Fiona Henderson

105

Utilizing Lead Isotope Tracing to Investigate Sustainable Agriculture Practice in the Burdekin
Catchment, Australia
Fiona Henderson, Barry Noller and Tatiana Komarova

111

Enhancement of Carbon Fiber Electrode Performance using Lactic Acid Bacteria and Steelmaking Slag
Narong Touch and Tadashi Hibino

118

Characteristics of Ion Components of Clearwater Stream Watershed in an Agricultural Area with
Multivariate Analysis
Yuri Yamazaki, Toshimi Muneoka, Chie Matsuda,
Masato Kimura and Osamu Tsuji

124

Evaluating Ion Exchange Capacity of Molten Slag for Hydroponic System
Antonio Perez Fuentes, Sarvesh Maskey, Hiromu Okazawa,
Yuri Yamazaki, Tomonori Fujikawa and Toshimitsu Asai

130

Some Physico-Chemical Characteristics of Surface Water in Mining Areas in the Lao PDR
Santi Kongmany, Vanseng Chounlamany,
Phetyasone Xaypanya, Oulay Phoupasong,
Bounthob Praxaysombath and Sindavanh Phengthavanh

136

Potential Use of Predatory Bug Eocanthecona furcellata for Biological Control of Plutella xylostella inChinese Kale Production
Jureeporn Sukhatiphum, Panida Kruaysawat, Nutcharee Siri,
Prakaijan Nimkingrat and Ubon Tangkawanit

142

Improving Water Quality of a University-Managed Biotope
Madoka Kurotaki and Machito Mihara

147

Design and Experimental Analysis of Atmospheric Water Generator Based on the Climatic Conditionsof Manolo Fortich, Bukidnon
Tan Jerico D. and Albiento Elizabeth Edan M.

152

DNA Fingerprinting of Selected Maize (Zea mays L.) Genotypes using SSR Markers
San Kyi, Kyaw Kyaw Win, Hla Than, Soe Win, Nyo Mar Htwe
and Aye Lae Lae Hlaing

158

Toxicity of Plant Essential Oil from Khok Phutaka Resources Protection Area, Khon Kaen Province
Against Storage Pest, Sitophilus oryzae
Duangrat Thongphak and Prapaporn Piangsuwan

164

Microbial Behavior in Cambodian Homemade-style Pickles
Shuki Muramatsu, Sokly Sorm, Masataka Uchino,Motoe Sekido, Yoshiki Muramatsu, Daiki Oka, Yuri Tanioka,
Takahiko Nakamura, Toru Nakajima, Mari Arimitsu andMachito Mihara

169

Impact Analysis of Population Growth and Fertilizer Use on Nitrogen Runoff in Nam Ngum Basin,
Laos
Koshi Yoshida, Issaku Azechi and Toshiaki Iida

176

Nursery Propagation of Apple Mangrove Sonneratia alba
Arnie C. Trangia

184

ii

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Research article
erdInteractions among Soil Physical, Chemical and Biological
Properties under Different Farming Systems
MARISOL TERASHIMA
Graduate School of Agriculture, Tokyo University of Agriculture, Japan
Email: chamiter@hotmail.com

MACHITO MIHARA*
Faculty of Regional Environment Science, Tokyo University of Agriculture, Japan
Email: m-mihara@nodai.ac.jp
Received 14 December 2020

Accepted 9 July 2021(*Corresponding Author)

Abstract The definition of soil quality has always been changing over time within the soil
science community. At first, the study focused more on chemical and physical properties
and less importance on a sustainable environment. Therefore, the definition of soil quality
has changed in the last decade. The importance of biodiversity that exists both on thesurface and within the soil began to be understood. These organisms have essentialfunctions such as nutrient cycling, provision of plant nutrients, and modification of physicalsoil structure, water regimes, and suppression of undesirable organisms on cropland. It has
defined soil quality as the function it has within the environment, sustaining productivity,
maintaining environmental quality, and promoting health in plants and animals. However,
the interaction between some microorganisms is still unknown, or how it could affect thedifferent parameters in the biodiversity of an agro ecosystem. Furthermore, it is unknown
what parameters are important in determining soil quality. Therefore, this study analyzed
the biological, physical, and chemical properties of the soil of two farms whose practices isdifferent. Water retention capacity, aggregate distribution, organic matter, total nitrogen,NO3, NH4, and biomass of microorganisms were measured. Soils were air dried and sieved
to 2mm. They were analyzed after drying in an oven at 105° C for 24 h. The biomass of
microorganisms was measured by the direct extraction method. The results indicated that
there was a significant difference between the microorganisms but could not be found withphysical and chemical properties. This result could indicate the importance of biologicalproperties over other parameters to discuss soil quality. In addition, the differences
observed could be explained by the different practices carried out on each farm.
Keywords soil quality, soil health, biomass of microorganisms, aggregates, total nitrogen

INTRODUCTION
Soil health is associated with soil biological parameters, such as biodiversity and its stability in theenvironment. When there are outbreaks of plant diseases, they are indicators of ecosysteminstability and poor health. Thus, healthy soil has the ability of the biological community tosuppress plant pathogens, the population of plant pathogens in the soil, and control the incidence
and severity of diseases (Bruggen van and Grunwald, 1996). Accordingly, Cruz (2004) defines soil
quality as dynamic, changing over time within the soil science community. At first, it was focusedmore on fertility, the yield of crops, and less importance on a sustainable environment. In otherwords, science has defined soil quality in chemical and physical parameters, such as the quantity orconcentration of nutrients, organic matter, and water retention.
In the last few decades significant efforts have been made to increase agricultural productivity
through increased fertilization and pesticide application, improved irrigation, soil management
regimes and crops, and massive land conversions (Tilman et al., 2002). There is increasing concern,
however, that agricultural intensification is placing tremendous pressure on the soil’s capacity toⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

maintain its other functions leading to largescale ecosystem degradation and loss of productivity inthe long term (Tilman et al., 2001; Foley et al., 2005; Vitousek et al., 2009). Since microorganisms
are involved in many soil processes, they may also give an integrated measure of soil health, an
aspect that cannot be obtained with physical/chemical measures alone (Nielsen et al., 2002;
Kibblewhite et al., 2008; Mueller et al., 2010; Sharma et al., 2011).
There have been a few reports that have indicated that organic farming practices have positiveeffects on soil microbial populations, processes and activities (Clark et al., 1998; Doran et al.,
1996; Drinkwater et al., 1995). Applications of insecticides may promote changes in population
biodiversity and dynamics by inhibiting or killing components of the soil microbial community.
Fungicide application can cause significant changes to the relative sizes of the bacterial and fungal
communities in soil (Sall et al., 2006; Sigler and Turco, 2002). Although most of the research has
shown increased microbial diversity in soils from organic farming systems compared toconventional farming systems, some studies have found different results. Shannon et al. (2002)
studied microbial communities in soils managed under organic and conventional regimes, andfound conflicting evidence that the size, composition and activity of the soil microbial biomass
were attributed to management practice. They found that differences in microbial communities insoils under different management practices were subtle rather than dramatic (Liu et al., 2007).
Therefore this study focus on analyzing some physical, chemical, and biological (themicroorganism communities) properties as indicator of soil quality / soil health of two agro
ecosystem which have different practices. In addition, the discussion about what parameters could
be important to determine soil health.
MATERIAL AND METHODS
Soils from 2 farms in Kanto Area, Japan, with a history of natural and conventional crop
production were sampled. These were sampled at a depth of the upper 5 cm of the soil. Soils were
air dried and sieved to 2mm. The dry weight of the soil was determined after drying in an oven at
105°C for 24 h.
The biomass of microorganism was measure by direct extraction method. Ten subsamples of
5.00 g of each soil were weighed separately into 50 ml centrifuge tubes and 20 ml of 0.5 M K2SO4
was added to each. To three subsamples, 0.5 ml of ethanol-free chloroform was added. Both thechloroform-exposed and the non-fumigated samples were capped and shaken simultaneously for 1
h. After shaking, the suspensions could settle for 10 min and the supernatants were filtered throughWhatman No. 42 filter. For the sub-samples with chloroform, only the top 15 ml of the supernatant
was filtered to reduce the amount chloroform in the filtrate. Filtrates from soils with and withoutchloroform were immediately bubbled with air for 30 min to remove any residual chloroform.
Blanks were treated in the same manner. Dissolved organic carbon in all filtrates was determined
after dichromate digestion by titrating with 0.033 M acidified ferrous ammonium sulphate(Anderson, et al. 1993). Chloroform labile C was calculated as the difference between the C
extracted from the chloroform fumigated and the non-fumigated sample. All results are expressedon an oven-dry basis. No conversion factor (kEC) was used to convert chloroform labile C tomicrobial biomass C because the range of kEC values (0.41 - 0.58) is used in the literature and it
has not been tested which is best suited for the soils used here (Setia et al., 2012).
In addition, number of culturable bacteria and fungus were quantified. The plate countmethodology by plating is a widely used methodology (Hoben and So-masegaran, 1982), which
consists of making 1:10 serial dilutions and spreading 100 µl of each dilution on a plate; plates are
incubated until colonies are countable.
The chemical and physical properties were measured as aggregate size, water retention
capacity, organic matter, total nitrogen, total phosphorus, nitrates, and ammonia. Soil samples
analyzed the aggregate's stability and distribution to observe the resistance in the water. Stability is
influenced by the physical and chemical properties of soils. In addition, the soil samples were
evaluated for their relationship with the organic matter.

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

For NO3 it was measured by nitration of salicylic acid (Cataldo et al., 1975) and for NH4 withindophenol blue method described by Searle (1984). Statistical analysis with ANOVA was done forall the treatments.
RESULTS AND DISCUSSION
Soil Physical and Chemical Properties

Aggregate %In Fig. 1 it shows us the distribution of soil aggregates. Soil aggregates play an essential role in theformation of soil structure and soil health. In agriculture, the stability of the aggregates is important
for the functioning of the agroecosystem. The pore spaces influence the storage of air and waterand the gas exchange. They create a habitat for soil microorganisms and allow the development andpenetration of plant roots. They also help in nutrient cycling and transportation.
It indicates that there are bigger aggregates in the conventional than in the natural one.
Although, no significant difference was found between the different agroecosystems. Thus, both
the Conventional and Natural ones mostly had aggregates greater than 0.5 mm.

Fig. 1 Aggregates (%) in both agroecosystems
Table 1 Soil organic matter (SOM) and water holding capacity in both agroecosystem
Agroecosystem

SOM (%)

Water holding capacity (%)

Conventional

11.82

76.67

Natural

6.18

61.5

No significance difference

The amount of organic matter in the soil depends on many factors, such as its rate of chemicaland biological oxidation, the rate of decomposition of organic matter already existing in the soil,
soil texture, aeration, humidity and climatic factors. Crop management practices can also influence
this parameter, since, for example, the use of mineral fertilizers accelerates the decomposition of
the organic matter in the soil. The water holding capacity depends on its texture, its structure, andthe depth of the roots. That is why the results relate to the fact that there is more organic matter,larger aggregates, and better retention in the conventional agroecosystem (Table 1).
These results may be related to conventional agricultural management. They use synthetic
fertilizers, fungicides, and pesticides, but they also make crop rotations and incorporate animal
manure as an organic amendment. On the other hand, in Natural Farm for many years, noamendments have been incorporated, only making crop rotations.
Table 2, total nitrogen analysis measures N in all organic and inorganic forms. Nitrate
nitrogen (NO3-N) is important because it is the primary form of nitrogen available to trees and,
therefore, an indicator of nitrogen soil fertility. However, soil concentrations of NO 3-N depend
upon the biological activity and may fluctuate with changes in soil temperature, soil moisture, andⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

other conditions. Nitrate is also easily leached with rainfall or irrigation. Most ammonia is
produced by bacteria in water and soil as a product of plant and animal waste decomposition. It isfound in relatively low nontoxic concentrations in soil and provides a source of nitrogen for plants.
Ammonium rarely accumulates in soil because bacteria will rapidly convert the ammonium that is
not taken up by plant roots into nitrates (nitrification).
Table 2 Chemicals properties in both agro ecosystem
Agroecosystem

TN (mg/kg)

TP (mg/kg)

NO3 (mg/kg)

NH3 (mg/kg)

Conventional

2343.33

267.140.15

6.86

Natural1563.33

370.000.13

5.57

No significance difference

Even the results are no significance difference, indicate that there was a higher level ofnitrogen in the Conventional Farm than in the Natural ones, but, in the total phosphorus, the casewas the opposite. P deficiency being common in weathered and tropical soils throughout the world,by rising costs of P fertilizer, and because efficiency of P use by plants from soil and fertilizer
sources is often poor despite containing a relatively large amount of total P that is sparingly
available to plants. Soil P exists predominantly in inorganic fractions that adsorb to mineral soil
surfaces or appear as poorly available precipitates and in organic forms that adsorb, incorporate
into biomass, or associate with soil organic matter (Richardson and Simpson, 2011). Although nosignificant difference was found, the value of TP in the Natural Farm is higher, which can indicate
related to the microbial biomass. Thus, it can also be related to the organic content, which was
higher in Conventional Farm. Other parameters need to be analyzed to be able to discuss themfurther.
Soil Biological Properties
Soil microorganisms affect attributes like aggregate formation and water movement. In addition to
fertility, soil microorganisms also play essential roles in the nutrient cycles that are fundamentally
important to life on the planet. The microorganisms that live in the soil and interact with the othercomponents, varies greatly depending upon conditions and it is highly complex and dynamic. The
most numerous microbes in soil are the bacteria, followed in decreasing numerical order by theactinomycetes, the fungi, soil algae and soil protozoa. Soil microorganisms are both components
and producers of soil organic carbon, a substance that locks carbon into the soil for long periods.
Abundant soil organic carbon improves soil fertility and water-retaining capacity.
Table 3 indicates that in the number of colonies formed in both fungi and bacteria there weremore in the Natural agroecosystem. In addition, soil microbial biomass also it was found more in
Natural agroecosystem than Conventional agroecosystem. Although with these results its richness
and abundance of species cannot be determined, it could be thought that microorganisms are
essential to maintain a healthy soil. This is because in the Natural Farm, for more than 20 years notype of amendments has been incorporated. It is that its maintenance of functioning in the soil
depends 100 percent on the internal activity that exists between microorganisms, plants andorganisms that live in the environment and soil. They could not be correlated with the chemical andphysical properties, but this can be thought to be related to the management that the Conventional
agroecosystem had. The Conventional agroecosystem, add manure, synthetic fertilization,
pesticides and fungicides. Pesticides and fungicides are known to affect the microbial population
rapidly, which may be the reason why there is less in the results obtained. In addition, anotherpractice that they carry out is weeding. In Natural Farm, they only weed in the first growth stage ofthe crop. On the other hand, in the Conventional Farm, they try to keep the soil without weeds. This
practice could be affecting microorganisms. According to Massenssini et al. (2014), the soil
microbial community structure might change depending on the crop species. Studies have shownthat the relationships of weeds and crops with the soil microbiota may be different. Weeds seem toⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

show higher dependence on interactions with soil microorganisms. The structure of the soil
microbial community is responsive to competition between plants. In general, the competition
promotes changes in the soil microbial community structure, making it different from that foundwhen plants are grown in monoculture. Furthermore, weeds tend to have positive feedback
interactions with soil microorganisms, while crops may present neutral or negative feedback
interactions.
Table 3 Biological properties in both agro ecosystem
Agroecosystem

Number of colony forming units/g dry soil
Total culturable fungi
Total culturable bacteria

Total microbial
biomass (μg/g)

Conventional

6.92 x 101a3.15 x 103A

0.16α

Natural1.71 x 103b1.10 x 104B

0.22β

a, A, α significance difference p> 0.05

CONCLUSION
The difference between both farms is by using fertilizers and pesticides. The Natural Farm is not
adding any amendments for 20 years. Furthermore, Conventional Farm use more manure thanchemical fertilizers. Pesticides affect the survival of soil microorganisms more severely than otherpractices carried out by the farm. The diversity of plant roots helps to maintain soil microorganism
diversity and abundance.
Interdisciplinary soil research is necessary to better understand the biological properties of soil.
To maintain the sustainability of the production it is necessary to maintain the population of soil
microorganisms. Further research is needed to understand the correlation with chemical andphysical properties. As well as to begin to understand the function that each group of bacteria andfungi has, its relationship with other living organism in the soil.
The production system influences the diversity of arthropods and microorganisms in an
agricultural ecosystem. Therefore, if a system cannot conserve or increase agricultural landbiodiversity, it will be more unstable and poor health of the soil ecosystem.
ACKNOWLEDGEMENTS
I would like to express my gratitude to Nakamura farm as well as the people of the NPO Tagayasu,
who gave me the opportunity to take the samples from their farms.
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populations as assessed by denaturing gradient gel electrophoresis. Applied Soil Ecology, 21, 107-118.
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Simberloff, D. and Swackhamer, D. 2001. Forecasting agriculturally driven global environmental change.
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Vitousek, M.P., Naylor, R., Crews, T., David, B.M., Drinkwater, E.L., Holland, E., Johnes, J.P.,
Katzenberger, J., Martinelli, A.L., Matson, A.P., Nziguheba, G., Oojima, D., Palm, A.C., Robertson, P.G.,
Sanchez, A.P., Townsend, R.A. and Zhang, S.F. 2009. Nutrient imbalances in agricultural development.
Science 324, 1519-1520, Retrieved from DOI https://doi.org/10.1126/science.1170261Ⓒ ISERD

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Research article
erd

Farmers’ Organic and Inorganic Fertilizers Application andits Effects on Rice Productivity in Prey Chhor District,Kampong Cham Province
MUY LEANG KIM
Graduate School of Agriculture, Tokyo University of Agriculture, Japan
Email: muyleangkim70@gmail.com

MACHITO MIHARA*
Faculty of Regional Environment Science, Tokyo University of Agriculture, Japan /Institute of Environmental Rehabilitation and Conservation, Tokyo, Japan
Email: m-mihara@nodai.ac.jp
Received 7 July 2021

Accepted 18 October 2021(*Corresponding Author)

Abstract Kampong Cham Province is located in plain region of Cambodia. The major
activity of people in the province is agriculture, mainly cultivating rice and vegetables.
More than 60% of farmers in Kampong Cham Province applied chemical fertilizers
inappropriately without understanding on its impacts. The use of high rates of chemicalfertilizers continuously for several years, often lead to unsustainability in production andpost harmful to the environment. Recent years, with the support from the government andnon-governmental organization (NGOs), many farmers realized and look for a better
agricultural practice which could harmonize with natural environment and human health.
Several practices were carried to promote the use of organic fertilizers such as green
manures, compost, and bio-liquid fertilizer in Kampong Cham Province. The use of organic
fertilizers it can reduce the input of chemical fertilizer, improve soil, water, andenvironment quality. Therefore, the objectives of this study are to describe farmers’
practices on fertilization and discuss the effect of fertilization practices on productivity inSamraong and Baray Communes. Ones hundred farmers were selected for interview withquestionnaire surveys on agricultural practices in Samraong and Baray Communes. The
results from the questionnaire surveys showed that more than 70% to 80% of farmers inSamroang and Baray Communes applied organic in combination with inorgnaic fertilizers
and less than 20% use only inorganic fertilizers and 10% only organic fertilizer. The
amount of rice production in each fertilization practices was different, the rice production inorganic fertilizer practices was high compared to other fertilization practices in Baray
Commune, however, in Samraong Commune the rice production was high in chemicalfertilization practices. As farmers in Samraong Commune used more chemical that is why
the production was high compared to other fertilization practices.
Keywords organic farming, inorganic fertilizers, compost, sustainable agriculture,
Kampong Cham

INTRODUCTION
Plant nutrients are essential for the growth and productivity of crops. Farmers supply nutrients inthe form of organic and inorganic fertilizers. Recently, farmers in Asia have increased the use of
inorganic fertilizers over organic fertilizers, however, integration of both organic and inorganic
fertilizers helps to increase crop productivity, soil fertility and decreases the damage that can be
introduced by inorganic fertilizers. Moreover, farmers in Kampong Cham Province still lakeknowledge regarding the advantages and disadvantages of applying organic and inorganic
fertilizers.
Kampong Cham Province is located on the plain region of Cambodia. The province consistsof 9 districts and 1 municipality, 109 communes and 916 villages. The total population of thisⒸ ISERD

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province is about 1.6 million people in 2013 (JICA, 2013), which accounts for 12.5% of the total
population of Cambodia. The population is comprised of 80% farmers, 1% craftsmen, 14% service
providers and 5% engaged in other businesses. Agriculture activities of people in Kampong Cham
Province are changing from subsistence to commercial monoculture with increased use of
inorganic fertilizers.
Organic and inorganic fertilizers are important for achieving an increase in crop productivity(Tong, 2010), if there is enough supply of nutrients to the soils, crop will grow well and produce
high yields. Application of organic fertilizers, compared to inorganic fertilizers, maintain soil
quality by increasing soil organic matter as well as improve soil physical and chemical properties
through decomposition of its substances (Mader et al., 2002). Additionally, Farmers in Baray
Commune, Prey Chhor District of Kampong Cham Province has been applied organic fertilizers formore than 10 year which results in better soil properties with organic fertilizer application.
Compared to that in Samraong Commune, farmers applied organic fertilizer for only 5 years inresults there was not clearly shown the influence of organic fertilizer application on soil properties(Kim and Mihara, 2018). Therefore, the study focused on investigating farmers fertilization
practices and the effect of fertilization practices on n productivity in Samraong and Baray
Communes, Prey Chhor District, Kampong Cham Province.
OBJECTIVE
The objectives of this study are to investigate and describe farmers’ fertilization practices and to
discuss the effect of different fertilization practices on rice productivity in Samraong and Baray
Communes.
METHODOLOGY
Study Site
The study is focused in Samraong and Baray Communes in Prey Chhor District, Kampong Cham
Province (Fig.1).
Cambodia

Prey Chhor District
Kampong Cham Province
Baray

Samraong

Fig. 1 Maps of the study areas and location of Samraong and Baray Communes, Prey Chhor
District, Kampong Cham Province
Samraong Commune consists of 11 villages and 1,714 households, the farmers in this commune
own cultivation land less than 1 ha. The main crops produced are rice and vegetables with main soil
types being brown hydromorphics, regurs and cultural hydromorphics. The number of farmers thatapplied chemical fertilizer or inorganic fertilizers were 1,587 out of 8,123 peoples.
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Baray Commune consists of 13 villages, 2,446 households, with average cultivation land lessthan 1 ha. The main crops cultivated are rice and vegetables. The soil types are the same in bothcommunes, In Bary Commune, 1,479 farmers out of 10,637 people used chemical fertilizer (CDB,2010).
Data Collection and Analysis
Secondary data collection: Relevant documents were collected from the research institutions
journals and reports of the project implement and the experts who had studied in the study areas.
Primary data collection: Ones hundred farmers were selected randomly for interview inSamraong and Baray Communes. The contents of the interview and questionnaire surveys mainly
focused on the general information of farmers, and agricultural condition, especially on soil fertility
management.

Fig. 2 Conducting questionnaire survey
Data analysis: To describe farmers fertilization practices and amount of fertilizer applied, total
nitrogen was used for calculating the amounts of fertilizers used in the study areas. Based oninterview and questionnaire surveys the total amounts of nitrogen applied in each fertilizer was
calculated with equation (1). Based on total amount of nitrogen applied, the degree of organic andinorganic fertilizers dependency was calculated with Equations (2) and (3).
Total N (kg/ha/yr)(1)

Organic Fertilizer Dependence (OFD%)

× 100

Inorganic Fertilize Dependence (IFD%) = 100 – OFD%

(2)
(3)

RESULTS AND DISCUSSION
Types of Fertilizers Uses among Responded Farmers
Based on the interview and questionnaire survey on fertilizers practices of farmers in Samraong
and Baray Communes showed that farmers applied Urea and Diammonium phosphate (DAP) as
inorganic fertilizers and manures and composts as organic fertilizer. The Urea, DAP and manure orcompost fertilizer all contained nitrogen content. The commercial rate of nitrogen content in Urea
is 46% and DAP is 18%. However, Kim and Mihara in 2018 analyzed the nitrogen content in Urea,
DAP and manure used by farmers in Samraong and Baray Communes showed that the nitrogen in
inorganic fertilizers were low compared to the commercial rates (Table 1).
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Table 1 Common types of fertilizers applied and the nitrogen content of fertilizers
Name

Chemical formulae

N%

N% *

Urea
Diammonium phosphate (DAP)
Manure or compost

CO(NH2)2

46
18

43.37
15.43
0.36

(NH4)2 HPO4

* Nitrogen content by Kim and Mihara, 2018

Fig. 3 Chemical fertilizer (left) and compost manure (right)

A*

B*

A*
A* A*
B*

Fig. 4 Amounts of fertilizer applied in
Samraong and Baray Communes

Fig. 5 Amounts of nitrogen applied in
Samraong and Baray Communes

Farmers in Samraong and Baray Communes applied Urea in average is 424 kg/ha/yr and 117
kg/ha/yr, DAP is 320 kg/ha/yr and 63 kg/year/ha, and manure is 8,768 kg/ha/yr and 8,968 kg/ha/yr,
respectively (Fig. 4). The amounts of fertilizers used in each fertilization were converted to theamounts of nitrogen contents (Fig. 5). As the results showed fertilizers applied in both Samraong
and Baray Commune were significantly different in 95%, especially in inorganic fertilization
practices. Farmers in Samraong Commune applied higher inorganic fertilizers than farmer in Baray
Commune.
Farmers’ Fertilization Practices
Farmers in Samraong and Baray Communes practiced organic, chemical, and organic in
combination with chemical fertilizers. There were 4%, 12% and 84% of farmer household who
applied organic, inorganic, and combine in Samraong Commune, respectively. 8%, 16% and 76%
of farmer applied only organic, inorganic, and combine in Baray Commune, respectively (Fig. 6).
As the result, both communes are likely combining organic and inorganic fertilizers for agricultural
production.

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Fig. 6 Comparison between farmer households who applied different fertilizers inSamraong (left) and Baray Communes (right)
The amounts of nitrogen used in Samraong and Baray Communes in each fertilization
practices were different. In Samraong Commune, nitrogen usage was high in inorganic fertilization
practices and combine compared to organic fertilization practices. However, in Baray Commune
the amounts of nitrogen use in organic, inorganic, and combine were not different. As comparing
the nitrogen use in both communes showed that farmers in Samraong Commune applied more
nitrogen in inorganic fertilizers and combine of organic and inorganic fertilization practices.

A*A*

Different letters
indicate * p<0.05

A*

A

A

B*

B*

Fig. 7 Average amounts of nitrogen applied in each fertilization practices (kg/ha/yr)
in Samraong and Baray Communes

Different letters
indicate * p<0.05

Fig. 8 Amounts of rice production (kg/ha/yr) in Samraong and Baray Communes

Effect of Different Fertilizer Practices on Rice ProductivityⒸ ISERD

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The amounts of rice production were significantly different at 95% interval in each fertilization
practices in Samraong and Baray Communes. Comparing rice production between Samraong andBaray Communes showed that the rice production shown higher in organic and combine of organicand inorganic fertilizer practices in Baray Commune (Fig. 8). Also, the rice production was notdifferent in inorganic fertilization practices in both communes. It was considered that organic
fertilizer application helps to increase the rice productivity in Baray Commune. As farmers in
Baray Commune applied less chemical and more organic fertilizer for long term, when organic
fertilizer has been applied for long time, the production was high indicating on good soil quality.

Fig. 9 Amounts of rice production (kg/ha/yr) in Samraong (left) and Baray Communes (right)

There was positive ration between organic fertilizer dependence (OFD%) and rice yields per
nitrogen applied at 95% confidence interval in Baray Commune. The combine of organic fertilizer
from 50% to 60% with inorganic fertilizers showing good results to increase the productivity in
Baray Communes (Fig. 9). However, in Samraong Commune the good rate of organic fertilizer in
combination with inorganic fertilizer was from 30% to 40%. As the results the combined
application of organic fertilizers such manures or compost and inorganic fertilizer enhanced tiller
number, panicle length and yield attribute of rice compared to only inorganic fertilizers application(Kakar et al., 2020).
CONCLUSION
Farmers in Samraong and Baray Communes combined organic and inorganic fertilizers, there arealso a few farmers who applied only organic or only inorganic fertilizers. The main sources ofnitrogen for farmers in Samraong Commune are likely from inorganic fertilizer, while in Baray
Commune the sources of nitrogen both from organic and inorganic fertilizers. The use of nitrogenin Samraong Commune in inorganic fertilization practice and combine was higher, while the riceproduction was lower compared to Baray Commune. Farmer in Samraong applied more inorganic
fertilizer, but the rice production was not different compared to Baray Commune when farmers
applied fewer inorganic fertilizers. Organic fertilizer application helps to increase in riceproductivity in Baray Commune, as farmers in Baray has been applied organic fertilizer for morethan 10 years and less inorganic fertilizers. It was considered that when organic fertilizer has been
applied for many years like Baray Commune, the production was high in organic fertilization andcombined. Inconclusion of more organic fertilizer and less inorganic is strongly recommended tofarmers in Samraong and Baray as organic fertilizer contributed to increase the rice productivity.
REFERENCE
Japan International Cooperation (JICA). 2013. Economic census of Cambodia 2011. Provincial Report 03
Kampong Cham Province, National Institute of Statics, Ministry of Planning, Phnom Penh, Cambodia.
Kakar, K., Xuan, D.T., Noori, Z., Aryan, S. and Gulab, G. 2020. Effects of organic and inorganic fertilizer
application on growth, yield, and grain quality of rice. Agriculture, 10 (11), 544.
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Mäder, P., Fliessbach, A., Dubois, D., Gunst, L., Fried, M.P. and Niggli, U. 2002. Soil fertility andbiodiversity in organic farming. Science, 296, 1694-1697.
Muyleang, K., Nakajima, T. and Mihara, M. 2018. Comparison of soil properties of farmlands applied withorganic and inorganic fertilizers in Kampong Cham Province, Cambodia. International Journal ofEnvironmental and Rural Development, 9 (1), 135-141.
Theng, V. 2012. Fertilizer value chains in Cambodia: A case study in Takeo Province. Cambodia
Development Review, 16 (4), 5-9.
Tong, K. 2010. Agriculture as the key source of growth: A focus on paddy rice production. Presentation to
the Cambodia Outlook Conference, 17 March 2010, Phnom Penh, Cambodia.
Working Group of Decentralization and Deconcentration and Sethkomar Ministry of Planning. 2012.
Commune data base (CDB). 2010. Poverty Reduction by Capital, Province, Municipalities, Districts,
Khans and Communes, Sangkats, Cambodia.

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Research article
erd

Shedding Light on the Gender Gap in Cambodia’s
Agriculture Sector - A Case of Agricultural Cooperation in
Kampong Cham Province
MARI ARIMITSU*
Extension Center, Institute of Environmental Rehabilitation and Conservation, Japan
Email: m.arimitsu@gmail.com

SHINOBU YAMADA
Research Center, Institute of Environmental Rehabilitation and Conservation, JapanKUMIKO KAWABE
Extension Center, Institute of Environmental Rehabilitation and Conservation, Japan

MACHITO MIHARA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Japan
Received 21 September 2020

Accepted 26 November 2021(*Corresponding Author)

Abstract This study deals with the status of women who engage in agricultural practices in
Kampong Cham Province, Cambodia. Specifically, it dissects the selection processes todetermine which gives participant farmers access to training opportunities provided by aninternational non-governmental organization. The research was conducted to provide
gender-disaggregated data while elucidating the gender gap that exists in opportunities forequal participation in and access to training and women’s role within Cambodia’s
agricultural sector based on data analysis for the baseline survey and key informant
interviews. This study concludes that there are specific gender roles, norms and biases,
either visible or invisible, embedded and/or expected in the local community. These traits
were manifested by participant farmers as well as officers who were responsible inselecting farmers. Individual interview revealed that gender norms regarding men as thehead of the house and illiteracy were mentioned as two possible factors hindering womenfrom participating in agricultural training, but when leaders who were responsible inselecting farmers were mindful about equal gender ratio, they could bring equal numbers offemale participants. In order to ensure gender equality in access to skills development
opportunities in the agricultural sector, trainings should focus on building effective
program, and optimizing and acknowledging current female farmers’ roles andcontributions in the agricultural and development sector of the rural economy.
Keywords gender equality, sustainable agriculture, rural development

INTRODUCTION
A global commitment, Sustainable Development Goal No. 5, is a stand alone goal to end all kindsof discriminations against women and girls and also to empower them (United Nations). Similarly,
Cambodia’s 5-year strategic plan (Neary Rattanak) is designed to support women to access andclaim their right to fully participate and benefit from economic and social development, and also
participate as decision makers. Agricultural extension services play an essential role in agriculturaldevelopment, poverty reduction, and food security (Feder et al., 2011), but women often lack theresources and opportunities they need, and face more severe constraints than men in accessing
productive resources, markets and services (Raney et al., 2011). Agricultural extension services are
particularly needed by smallholder farmers in developing countries as they usually have low levelsⒸ ISERD

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of education and limited access to information and resources to enhance their capacity and level ofproductivity.
The project on “Promoting Sustainable Agriculture Conditions for Poverty Reduction in
Kampong Cham Province” is currently being implemented by an international organization basedin Japan. The target populations are more than 25 local agriculture extension officers and 1,500
local farmers in the region where agro-chemical and their improper application is prevalent.
According to FAO statistics, Cambodia’s total fertilizer use increased from 38,693 tons in 2005 to
134,053 in 2018. The project was designed to alleviate farmers’ poverty and improve theirlivelihood conditions by intoroducing and disseminating sustainable agricultural practice.
Throughout the project, participant smallholder farmers have learned the techniques of sustainableagriculture, including composting, pellet composting, pest and disease management so that they
can reduce the use of synthetic products which economically burden them and are harmful to thehuman bodies and environment. In the third year of the project, they will gain techniques on thecollecting and shipping process so that they can sell their safer products with added price. The
objectives of this study are 1) to elucidate the situation of the women’s participant to the trainings
that are to eradicate the poverty and bring knowledge and technique on sustainable agricultural
practice and analyze the participation rate and the cause of it, and 2) to conduct analysis based on
the interview over women’s role and contribution to the agricultural management, which includes
the management of the marketing, and the needs of the training.
METHOLODOGYThis study adopted both quantitative and qualitative approaches. The baseline survey of 500
principal farmers gathered in 2018 were examined in order to recognize the gender disaggregateddata and elucidate the situation of the women’s participant to the training. Additional key informant
interviews with 40 individual female farmers and ministry officers were conducted in 2019 tocomplement the information which was missing from the original baseline survey. The interview
was structured in accordance with the gender analysis, which examines how the roles, rights, andresponsibilities of men and women interact and how that affects outcomes (Doss, 2013). The semistructured questions were particularly focused on intersection between gender and recruitment,
participation and women’s roles and their needs in the region: 1) the process of how they wereselected, 2) gender roles in agricultural practice, what are their everyday work in the field and at
home, 3) does the training provided by the organization meets the needs and requests of women.
Analysis included looking at the gender norms and the implications of those relationships on
women’s ability to participate in the training on sustainable agriculture. Interviewees were theparticipants and beneficiaries of the three-year project who know what is going on in the field.

Fig. 1 Location of the study area of Kampong Cham Province and 10 districts
The target population was selected across nine districts in Kampong Cham Province that is
Prey Chhor, 8; Batheay, 6; Srei Santhor, 3; Cheung Prey, 8; Kampong Siem, 5; Kang Meas, 2;
Kaoh Soutin, 1; Stueng Trang, 5; and Chamkar Leu, 2. Farmers were selected based on availability
and willingness to take part after the training.
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RESULTS AND DISCUSSIONThe Status of Female Participant’s Rate
After the initiation of the project in 2018, a baseline survey was conducted targeted 500
participating farmers and was examined as gender segregated data. The baseline survey shows thatthe principal farmers consisted of 333 male participants (67%) and 167 female participants (33%).
Out of 500 particicpants, 119 male participants (36%) and 59 female participants (35%) answeredthat they belong to some agricultural group in their villages. The opportunities provided were
geographically varied as only four female farmers belong to compost and safe vegetable groups in
Kampong Cham District, whereas nine female farmers and 27 male farmers belong to various
agricultural groups in Stueng Trang District. The average size of their agricultural land is 1.07ha.
The educational background was categorized by 1) Never been to school, 2) Primary school, 3)Secondary school, 4) High school, 5) College, 6) University. For all age groups, on average, men
have a slightly higher educational background (2.43) whereas women’s average is 2.23. According
to the age group, both men and women hold particularly lower educational backgrounds in their
40s and 50s, particularly in their 50s (Female: 1.86, Male: 2.33). This can be from the fact that they
were directly effected by the internal conflict within Cambodia during the 1970s where people’s
educational opportunities were deprived. Cambodia’s gender gap in adult literacy rate issignificantly improved in recent years, but the gap remains for elderly populations (UNESCO,2015). The participants’ age varies, but the average age of male participants is slightly higher thanfemale participants (Female: 45 and Male: 47). The baseline survey didn’t specify whether thehousehold is either female or male. Hence, the income gap between male and female participants is
not obtained. When they were asked what techniques they need, female farmers were particularlyinterested in seeds (48%), organic fertilizers (47%), planting (35%), and marketing (28%), whereas male farmers showed their interests in organic fertilizers (47%), seeds (44%), planting (30%),
and marketing (27%).

Fig. 2 Technical training on pest and disease management (farmers making bio-pesticide)
The first training for 500 principal farmers was conducted from December to March 2018 withthe theme of “Improvement of Soil Fertility”. It was a one-day training held in two different
communes from 8:00 a.m. to 4:30 p.m. The venue was optimized in each district such as model
farmers, Department of Agriculture offices, or community space. The training covered the role andfunction of soil in agricultural land, compost, pellet compost, and liquid fertilizers, and was led bytrained ministry officers. The training included a demonstration on how to make compost andliquid fertilizers. The second training for the same principal farmers was conducted from January to
March 2019 with the theme of “Pest and Disease Management” with adjustment of the time for themorning session to cocomplete earlier so that female farmers can return back their home for lunch
preparation. The training focused on Integrated Pest Management (IPM), proper use of chemical
fertlizers, and technical and practical knowledge about pest and disease control. The training also
included a demonstration on how to make bio-pesticide (Fig. 2).
According to Table 1, the participating numbers of women were disproportionately small
compared to that of men. However, in Cheung Prey, Kampong Cham, Kampong Siem Districts, theⒸ ISERD

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female farmers were closer to half of the participants. In contrast, in Chamkar Leu District, thenumbers of female participants were only 16% (Table 1).
Table 1 Numbers of principal farmers in the baseline survey conducted in 2018
District

Batheay

Chamkar
Leu

CheungPrey

Kampong
Cham

Kampong
Siem

Kang
Meas

Kaoh
Soutin

Prey
Chhor

Srei
Santhor

Stueng
Trang

72%

84%

58%

54%

51%

72%

58%

69%

72%

74%

28%

16%

42%

46%

49%

28%

42%

32%

28%

26%

Male
(%)
Female(%)

Source: Baseline Survey and List of Participants for Improvement of Soil Fertility in 2018

The individual interviews with the female farmers revealed how individual participants werechosen: 1) the specific individual participant was directly appointed by the local authority, or 2) the
household of the participant was appointed by the authority, then a discussion was held within thehouse to designate the actual participant. Out of 35 participants interviewed, five answered thatthey were directly appointed by the authority. Four answered that the authority appointed theirhusbands. In the remaining 26 cases, participant selection was done within the family members
based practical reasons such as availability and not on the notion that in a traditional gender role
the important meetings and trainings are attended by men. Several farmers decided to rotate
participation during the course of the trainings. One of the interviewees in Batheay said she was
encouraged by the authority to rotate the participation when they are busy. The participants were
mostly either husband or wife, but a few interviewees rotated the participation with their children.
There were eight cases where husbands work in a non-farming sector, especially during the dry
seasons from around December to May in Cambodia. One has gone to the Thailand to generate
more income. 12 female farmers out of 35 participants came to the second training on “Pest andDisease Management” instead of their husbands or other family members. Hence, male and female
participation is fluid, and the analysis of the baseline survey data may not cover the actual genderratio as well as gender segregated data of the participants. The rate of the female participants was
dramatically increased in some districts for the second training. For instance, in Cheung Prey, maleparticipants in the first theme of the training, Soil Fertility, outnumbered the female, but at thesecond training on the theme of the Pest and Disease Management, female numbers significantly
increased (Table 2).
Table 2 Numbers of principal farmers who participated in the second training in 2019
District

Batheay

Chamkar
Leu

CheungPrey

Kampong
Cham

Kampong
Siem

Kang
Meas

Kaoh
Soutin

Prey
Chhor

Srei
Santhor

Stueng
Trang

-

85%

14%

60%

47%

58%

64%

66%

52%

63%

-

15%

85%

40%

53%

42%

36%

34%

48%

37%

Male
(%)
Female(%)

Source: List of Participants for Pest and Disease Management in 2019

The key informant interview was also conducted with five chief ministry officers, consistingof one female and four males, who were responsible of selecting participant farmers. The officers
from Cheung Prey and Kampong Siem noted their participants were selected by a Village Leader
and a Commune Leader. For Cheung Prey District, the two leaders were sensitive to the genderratio and tried to have equal numbers of male and female participants, although the officer himself
was not aware of it. Similarly, a female officer in Kampong Siem wasn’t aware of the genderneither ratio nor gender equality, but the leaders were. Prior to this project, both districts haveprovided some trainings on microfinancing and chicken raising specifically to female farmers.
Evidently, the ratio of female participants was higher in those two districts compared to other
districts (Table 1 and 2). The officer in Srei Santhor said he was conscious about gender equality
and selected the participants simply based on people who are more actively engaging in agriculture,
however, the female participant rate was relatively low in the two trainings. Additionally, thefemale participation rate was significantly low in Chamkar Leu District (Tables 1 and 2). A maleⒸ ISERD

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officer from Chamkar Leu answered that they appointed the household along with the Village
Leader, and appointed the persons who actually do the farming and those are naturally males. Other
noted from Chamkar Leu District that as much as they wish to include females, when they visitedtheir houses, they usually ask their husbands who are the head of the house to respond to theofficers. A male officer from Prey Chhor mentioned that females are relatively illiterate and they
are not willing to join this kind of training. Gender norms regarding men as the head of the houseand illiteracy were mentioned as two possible factors hindering women from participating in
agricultural training, but when leaders who were responsible in selecting farmers were mindful
about equal gender ratio, they could bring equal numbers of female participants.
The Roles of Female in Agricultural Practice and Access to Market
In this section, this paper will discuss about the roles and contributions of the female farmers intheir agricultural practices in Kampong Cham Province. In details, the interview was conducted to
study if there are any particular work that female farmers bear and also what kind of trainings areneeded in the area. According to the key informant interviews with 35 farmers, specific genderroles exist in agricultural practices in the region. Most of the female interviewees answered thatthey engage in broad tasks such as soil preparation; preparing, making and applying the fertilizer
and compost; sowing; collecting weeds; and drying rice after products are harvesting; and selling
the products was largely taken care by women, whereas men engage in seemingly physically harderand mechanical tasks such as ploughing, harvesting, and spraying the pesticides. When they are
raising the vegetables, female farmers bear more tasks including the harvesting. Most of theinterviewees sell the products to the middle persons, and women are actively involved in thenegotiation process. In the case of a single mother or a woman whose husband is disabled or
working in the non-agricultural sectors, they employee other men and women to engage in theirfields. Some of them bear more tasks than other women who work with their husbands. They tend
to express more power than the other female interviewees, which was manifested by their use ofphrases such as “male and female can do the same”, “there are no specific gender roles inagricultural field”, and “the training being provided by the organization will equally benefit both
men and women”. On the other hand, women’s work in an agricultural field across the nine
districts was xpressed in words such as “small” and “not too much”, due to the gravity of thephysical workload.
At their households, all the female workers perform traditional gender roles: cooking, taking
care children and livestock, or growing vegetables around the houses. The male officer in Chamkar
Leu, too, generalized that house work is normally the work of women. Some of their husbands
support the wife’s role in doing such tasks carrying water, cooking, taking care of children. Manyof the interviewees were engaged solely in agricultural practice, but the interviewees also revealed
that a few female participant farmers engaged in work outside of the agricultural field, such as
working at a factory or crafting weed mattresses at home in order to seek the additional income forthe family. However, according to the participants, women face severe constraints due to lack ofknowledge and skills in a non-agricultural sector or their elderly age as factories or companies
favour younger women as their employees. A study by Gender and Development of Cambodia in2010 (Ministry of Women Affairs, 2014) noted that men perceive that they should fulfill the role as
the head of the house, and women perceive normalizing male privilege. Consequently, women tend
to see their capacity and power lower than men in the society. The interview showed that female
farmers bear broad range of agricultural practices as well as domestic work, but some of them seen
their ability lower than male partners, which may be based upon the traditional gender norms
prevailing in the country.
Lastly, female farmers expressed concerns about the fixed marking price provided by middle
persons. Some of them noticed that the selling price to the customer is a lot higher than the
farmers’ sold price, but they see that there is no way that they can increase the value of it. Out of 35
interviewees, 20 expressed the need of the marketing skills. A female farmer answered that there
seems to be no connection between the producer and the consumer because she sells it to a middle
person. They want to build a strong relationship between the two. Building a relationship betweenⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

the producer and customer is a growing trend in agriculture throughout the world, and this can bepromoted during the course of the project. Due to the low price that is given from the middle
persons, two female farmers tried to sell the products in the market, but they faced multiple
difficulties ranging from finding a spot in the market place to selecting a suitable price andattracting regular customers. One of them expressed the concern over transportation as she uses her
own motorbike that she cannot carry many products at one time. The access to the local market wasalso depending on the geographical location of the marketplace versus where they live. The above
two female farmers in Kang Meas and Kampong Siem Districts were able to access the local
market because it is accessible from their houses. The marketing skills will benefit women greatly
because majority of sellers in the market consist of female workers in Kampong Cham Province.
Participating female farmers shared the information and techniques with husbands or other family
members, and what they have learned is being practiced at their farmland. However, they are also
seeking other specific trainings such as raising chickens, ducks, cows, fish, and crafting that they
can do while doing the housework at home.
CONCLUSION
The knowledge gained in this study can be summarized as follows. First, regarding the trainings on
promoting sustainable agricultural conditions for poverty reduction, the 2018 baseline survey
showed that participating male farmers significantly outnumbered the female farmers. However,the participation in the second training revealed that the ratio of male and female participating
farmers is fluid as some of them rotate the participation in accordance with their availability. In two
districts, female farmers outnumbered the male farmers in 2019, where the persons who directly
involved in the election process were particularly aware of having the equal numbers of men andwomen. Interviews lso revealed the gender biased selection methods by the officers who were
responsible in selecting farmers at the initial stage. Secondly, female farmers bear broad range of
agricultural practices, even though some of them seen their ability lower than male partners, which
is based upon the traditional gender norms prevailing in the country. Female farmers would cometo the training if the content is related to their regular work that they do in the field, such as soil
preparation, pest and disease management, and the marketing. It is also a key to design the timing,
period, and venue of the training when female farmers can participate, as their reproductive work athome is widely normalized. Additional training and/or awareness raising may be necessary for the
local authorities who are responsible in selecting farmers in order to disrupt the gender biased
selection process. The interview with the female farmers mentioned the higher needs of the training
in marketing in the region, and some of the challenges they face. Their needs are also varied
beyond the basic agricultural techniques. Therefore, in order to reduce the inequality for female
farmers in getting agricultural information and knowledge, building an effective program based on
their actual regular agricultural practice is required.
REFERENCES
Doss, R.C. 2013. Data needs for gender analysis in agriculture. International Food Policy Research Institute,
1-13.
Feder, G., Birner, R. and Anderson, R.J. 2011. The private sector’s role in agricultural extension systems,
Potential and limitations. Journal of Agribusiness in Developing and Emerging Economies, 1 (1), 34-54.
Food and Agriculture Organization (FAO). FAOSTAT database, Fertilizer indicators, Cambodia. Retrieved
from https://www.fao.org/faostat/en/
Ministry of Women’s Affairs. 2014. Attitudes gender relations and attitudes cambodia gender assessment. 123, Cambodia.
Ministry of Women’s Affairs. 2014. Neary Rattanak 4. United Nations Development Programme.
Raney, T., Anríquez, G., Croppenstedt, A., Gerosa, S., Lowder, S.K., Matuschke, I. and Skoet, J. 2011. The
role of women in agriculture. ESA Working Paper, 11-02, Food and Agriculture Organization, United
Nations.

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United Nations, Department of Economic and Social Affairs. Sustainable Development. Retrieved fromhttps:// sdgs.un.org/goals/goal5
United Nations Educational, Scientific and Cultural Organization (UNESCO). 2015. Data for sustainable
development goals. Cambodia. Retrieved from http://uis.unesco.org/en/country/khⒸ ISERD

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Research article
erd

The Influence of Agricultural Production Information on
the Agricultural Management Scale in Rural Areas ofCambodia
SHINOBU YAMADA*
Research Center, Institute of Environmental Rehabilitation and Conservation, Tokyo, Japan
Email: sinobun4022@gmail.com

MARI ARIMITSU
Extension Center, Institute of Environmental Rehabilitation and Conservation, Tokyo, Japan

MACHITO MIHARA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanKUMIKO KAWABE
Extension Center, Institute of Environmental Rehabilitation and Conservation, Tokyo, Japan
Received 29 March 2020

Accepted 26 November 2021(*Corresponding Author)

Abstract The main object of this study was to quantitatively grasp the relevance among
local farmers to analyze the characteristics of local farming and agricultural production
information to build stable and sustainable farming needed by farmers. The research site
was ten districts in Kampong Cham Province, Cambodia. The results of the analysis are
summarized as follows: 1) It was confirmed that the index of agricultural production
information varies depending on the districts; 2) Based on the Canonical Correlation
Analysis results, cultivated land and annual income from agricultural activity, which are
regarded to be the results of agricultural management, have relevance among factors suchas attributions, crops, and agricultural production information was clarified. The cultivatedland is affected by the index, which is aimed at expanding the scale of rice production. In
addition, annual income from agricultural activity is affected by an index aimed at highquality crop production based on new technology information, information about organic
fertilizer and training. According to the results of the analysis, agricultural productivity
expansions in Cambodia depends on providing information that can be adaptable to theintention of agricultural management of the local farmers.
Keywords Cambodia, canonical correlation analysis, multiple farming

INTRODUCTION
In Cambodia, per capita income has increased along with economic development. Consequently, ademand for various agricultural products in addition to rice has increased resulting in increased
production of various agricultural products including vegetables. Currently, in rural areas, many
local farmers intend to produce rice as usual, while many farmers produce vegetables and fruits
using multiple farming. In order to mitigate poverty in rural areas, it is necessary to produce avariety of crops, centering on rice production, which is expected to expand in the future. The
building of stable and sustainable agricultural management is essential. According to thisbackground, the main object of this study was to quantitatively grasp the relevance among local
farmers in different districts to analyze the characteristics of local farming and agricultural
production information to build stable and sustainable farming needed by the farmers. In addition,
this study focuses on multiple farming in Cambodia.

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OBJECTIVE
The main object of this study was to quantitatively grasp the relevance among local farmers in
different districts to analyze the characteristics of local farming and agricultural production
information to build stable and sustainable farming needed by the farmers. The specific analysis of
this study has the following two issues: 1) the index of agricultural production information requiredby local farmers per district; 2) the Canonical Correlation Analysis applies to attributions, crops
and agricultural production information are associated with scale of cultivated land and annual
income from agricultural activity considered to be a result of farm management. The CanonicalCorrelation Analysis is used in quantitative analysis of the relation between the agricultural
management scale acreage allotment and regional structure (Ohtake and Aoyagi, 1988; Matsumoto,1998).
METHODOLOGY
The research site was in Kampong Cham Province. Kampong Cham Province is located northeastof Phnom Penh, and southeast of Siem Reap. During the French colonial period, in Kampong
Cham Province, the hilly terrain was developed as a rubber plantation zone. The population of
Kampong Cham province is approximately 1.75 million and much of the population is engaged inagriculture. The target area of the questionnaire survey consisted of the following ten districts:
Batheay district: 45 respondents (10.3% of the total respondents); Chamkar Leu district: 50(11.4%); Chueng Prey district: 36 (8.2%); Kaoh Sotin district: 46 (10.5%); Kampong Siem district:
38 (8.7%); Krong Kampong Cham district: 48 (11.0%); Kang Meas district: 44 (10.1%); Prey
Chhor district: 36 (8.2%); Srei Santhor district: 50 (11.4%); and Stueng Trang district: 44 (10.1%).
The total number of respondents is 471, and the number of valid respondents is 437. In Kampong
Cham Province, vegetables and fruit trees are widely produced while their main production is rice.
As for the vegetables, cabbage and cucumber are often planted and produced throughout the year.
Also, various vegetables and fruits including luffa, bitter melon, winter melon, Chinese spinach,leaf onion, lemongrass, green beans, papaya, and cashew etc. are produced. Additionally, at thissite, the Institute of Environmental Rehabilitation and Conservation (ERECON) carries out aproject on Promoting Sustainable Agricultural Conditions for Poverty Reduction in Kampong
Cham Province in Cambodia (October/2017-September/2020). This project aims to promotesustainable farming practices to local farmers based on the cyclic use of natural resources.

Fig. 1 Location of the study site in Kampong Cham Province
RESULTS AND DISCUSSIONⒸ ISERD

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The Index of Agricultural Production Information Required by Local Farmers per District
Table 1 shows the index of the questionnaire survey conducted, which contains categories forgender and age of the respondent, educational background, farm acreage, cropping pattern andfarmers' revenues. Table 2 shows segregated results of indicators showing the characteristics of the
agricultural production information for each district. In addition, multiple responses are gatheredregarding the agricultural production information. For each district, the following characteristics
are taken into consideration from the results in Tables 1 and 2.
Table 1 Average of agricultural management scale for each district
Number of response
All
Batheay

Index
Gender

1. Male2. FemaleAge
1.Less than 29 years old
2.30-39years
3.40-49years
4.50-59years
5.More than 60 years old
Educational 1. Never had been to school
background 2. Primary
3. Secondary
4. High school
5.College/University
Total
1.Less than 0.5 haarea
2.0.6-1ha
3.1.1-1.5ha
4.1.6-2ha
5.More than 2.1ha
Cropping
1.Ricepattern2.Vegetables
3.Fruitfarmers'
1.Less than 1,000,000 Rielrevenues
2.1,000,000-2,999,999 Riel
3.3,000,000-4,999,999 Riel
4.5,000,000-6,999,999Riel
5.7,000,000-8,999,999 Riel
6.More than 9,000,000 Riel
source ： Survey Date

Krong
Kampong
Kang
Prey
Srei
StuengKampong
Siem
Meas
Chhor
Santhor
Trang
Cham
437
45
50
36
46
38
48
44
36
50
44
(n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%)
282 64.53 32 0.71 42 0.84 16 0.44 26 0.57 19 0.50 25 0.52 34 0.77 20 0.56 36 0.72 32 0.73
155 35.47 13 0.29 8 0.16 20 0.56 20 0.43 19 0.50 23 0.48 10 0.23 16 0.44 14 0.28 12 0.27
17 3.89 2 0.04 3 0.06 0 0.00 1 0.02 2 0.05 0 0.00 1 0.02 1 0.03 3 0.06 4 0.09
113 25.86 15 0.33 20 0.40 7 0.19 6 0.13 10 0.26 7 0.15 14 0.32 7 0.19 8 0.16 19 0.43
140 32.04 21 0.47 15 0.30 9 0.25 20 0.43 12 0.32 15 0.31 17 0.39 9 0.25 10 0.20 12 0.27
116 26.54 2 0.04 7 0.14 12 0.33 16 0.35 11 0.29 17 0.35 6 0.14 18 0.50 22 0.44 5 0.11
51 11.67 5 0.11 5 0.10 8 0.22 3 0.07 3 0.08 9 0.19 6 0.14 1 0.03 7 0.14 4 0.09
42 9.61 5 0.11 3 0.06 7 0.19 2 0.04 0 0.00 14 0.29 2 0.05 0 0.00 2 0.04 7 0.16
228 52.17 24 0.53 34 0.68 21 0.58 20 0.43 22 0.58 17 0.35 20 0.45 18 0.50 25 0.50 27 0.61
133 30.43 14 0.31 11 0.22 5 0.14 19 0.41 13 0.34 14 0.29 14 0.32 17 0.47 20 0.40 6 0.14
33 7.55 2 0.04 2 0.04 3 0.08 5 0.11 3 0.08 2 0.04 8 0.18 1 0.03 3 0.06 4 0.09
1 0.23 0 0.00 0 0.00 0 0.00 0 0.00 0 0.00 1 0.02 0 0.00 0 0.00 0 0.00 0 0.00
91 20.82 5 0.11 15 0.30 5 0.14 0 0.00 13 0.34 30 0.63 7 0.16 9 0.25 5 0.10 2 0.05
116 26.54 14 0.31 13 0.26 10 0.28 17 0.37 11 0.29 6 0.13 11 0.25 18 0.50 11 0.22 5 0.11
117 26.77 12 0.27 10 0.20 14 0.39 13 0.28 6 0.16 8 0.17 16 0.36 3 0.08 25 0.50 10 0.23
40 9.15 8 0.18 3 0.06 1 0.03 7 0.15 7 0.18 0 0.00 5 0.11 1 0.03 3 0.06 5 0.11
73 16.70 6 0.13 9 0.18 6 0.17 9 0.20 1 0.03 4 0.08 5 0.11 5 0.14 6 0.12 22 0.50
394 0.36 43 0.46 34 0.27 35 0.36 45 0.36 32 0.32 42 0.35 38 0.32 35 0.43 48 0.35 42 0.44
389 0.36 37 0.40 48 0.39 31 0.32 43 0.35 35 0.35 46 0.38 42 0.36 33 0.41 50 0.37 24 0.25
307 0.28 13 0.14 42 0.34 32 0.33 36 0.29 33 0.33 32 0.27 38 0.32 13 0.16 38 0.28 30 0.3130
6.86 0 0.00 1 2.22 8 0.07 3 9.26 7 0.05 2 7.47 0 0.00 6 24.46 3 0.02 0 0.00
169 38.67 9 0.09 16 35.56 18 0.16 23 70.99 15 0.11 25 93.40 17 0.09 14 57.06 24 0.16 8 23.48
122 27.92 12 0.12 12 26.67 7 0.06 11 33.95 11 0.08 12 44.83 18 0.10 10 40.76 15 0.10 14 41.08
57 13.04 5 0.05 13 28.89 2 0.02 6 18.52 1 0.01 5 18.68 6 0.03 3 12.23 4 0.03 12 35.22
32
7.32 10 0.10 4 8.89 1 0.01 2 6.17 4 0.03 1 3.74 2 0.01 1 4.08 2 0.01 5 14.67
27
6.18 9 0.09 4 8.89 0 0.00 1 3.09 0 0.00 3 11.21 1 0.01 2 8.15 2 0.01 5 14.67
Chamkar
Leu

Chueng
Prey

Kaoh
Sotin

In Batheay District, the average annual agricultural income was the highest among the 10
districts. In the order of importance, they valued information about training, information aboutorganic fertilizer, and new technology information. For Chamkar Leu District surveys indicatedthat more vegetables and fruits were produced than rice, based on the local cropping pattern. The
farmers, in order of importance, valued information about organic fertilizer, new technology
information and information about seeds. In Cheung Prey District, the average agricultural annual
income is the lowest among the 10 districts and respondents have the highest average age. They
most valued information about seeds, followed by information about training and market. Kaoh
Sotin District has the third largest average management area among the 10 districts. The
agricultural production information that was answered as important was in the order of information
about seeds, information about organic fertilizer and market. In Kampong Siem District, it has thesecond lowest average management area and annual income out of 10 districts. The agricultural
production information that was answered as important was in the order of information about seeds,
new technology information and market information. In Krong Kampong Cham, it has the smallest
average management area, because it located in an urban area in the province. The agricultural
production information that was answered as important was in the order of information aboutorganic fertilizer, information about seeds and planting information. In Kang Meas District, half ofthe respondents graduated from secondary school and high school. The agricultural production
information that was answered as important was in the order of information about chemicalfertilizer, information about seeds and planting information. In Prey Chhor District, almost all local
farmers produce rice and vegetables, while fruits production is low. The agricultural production
information that was answered as important was in the order of planting information, informationⒸ ISERD

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about organic fertilizer and seeds. In Srei Santhor District, the farmers have the third lowest
average agricultural annual income among the 10 districts. The agricultural production informationthat was answered as important was in the order of new technology information, market
information, and information about seeds. In Stueng Trang District, the farmers had the youngest
average age, and the largest average management area. The average agricultural annual income wasalso high. They ranked agricultural production information as most important followed by,information about organic fertilizer, new technology information and information about seeds. The
composite questionnaire answers the index of agricultural production information varies among the
districts.
Table 2 Characteristics of agricultural production information for each district
Number of response
All
Batheay

Index
Agricultural
production
information

Information about seeds
Information about machinery
New technology information
Information about chemical fertilizer
Information about organic fertilizer
Market information
Information about training
Price information
Information about harvest
Planting information
Source ： Survey Date

Chamkar
Leu

Chueng
Prey

Kaoh
Sotin

Kampong Krong
Kang
Prey
Srei
StuengSiem
Kampong
Meas
Chhor
Santhor
Trang
Cham
437
45
50
36
46
38
48
44
36
50
44
(n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%) (n) (%)
194 0.44
8 0.18 14 0.28 29 0.81 28 0.61 22 0.58 22 0.46 24 0.55 17 0.47 13 0.26 17 0.39
26 0.06
0 0.000 0.005 0.14
1 0.02
8 0.21
2 0.04
4 0.09
1 0.03
2 0.04
3 0.07135 0.31 13 0.29 17 0.34 10 0.28 10 0.22 19 0.50 11 0.23 13 0.30
5 0.14 18 0.36 19 0.43
32 0.07
1 0.02
4 0.08
4 0.11
3 0.07
8 0.21
6 0.13
1 0.02
4 0.11
1 0.020 0.00
199 0.46 18 0.40 18 0.36 13 0.36 24 0.52 15 0.39 30 0.63 30 0.68 18 0.50 12 0.24 21 0.48
113 0.26
9 0.20 13 0.26 14 0.39 22 0.48 17 0.45
9 0.19
6 0.14
2 0.06 15 0.30
6 0.14117 0.27 24 0.53
2 0.04 19 0.53
5 0.11 15 0.39
8 0.17
9 0.209 0.25 10 0.20 16 0.36
32 0.07
2 0.04
1 0.02
8 0.22
6 0.13
6 0.16
1 0.02
2 0.050 0.001 0.02
5 0.11
15 0.03
0 0.000 0.004 0.11
2 0.04
4 0.11
1 0.020 0.000 0.000 0.004 0.09138 0.32
5 0.11 10 0.20 13 0.36 21 0.46
6 0.16 18 0.38 19 0.43 25 0.69
6 0.12 15 0.34

Table 3 Estimation results of canonical correlation analysis

IindexCultivated land
Annual income from agricultural activity
1 Gender2 Age
3 Educational background4 Rice5 Vegetables
6 Fruit
7 Information about seeds
8 Information about machinery
9 New technology information
10 Information about chemical fertilizer
11 Information about organic fertilizer
12 Market information
13 Information about training
14 Price information
15 Information about harvest
16 Planting information

：
：
：
：
：
：
：
：
：
：
：
：
：
：
：
：
：
：

Ｙ1
Ｙ2
Ｘ1
Ｘ2
Ｘ3
Ｘ4
Ｘ5
Ｘ6
Ｘ7
Ｘ8
Ｘ9
Ｘ10
Ｘ11
Ｘ12
Ｘ13
Ｘ14
Ｘ15
Ｘ16

（5 levels）（5 levels）（dummy)（5 levels）（5 levels）（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)（dummy)Canonical variables
standardized coefficients
CV1
CV2
0.99580.34760.0129-1.0547
0.04670.2559-0.2296-0.26130.25340.07480.698-0.1882-0.259-0.02440.296-0.5674-0.3184-0.30510.1119-0.06290.10610.2414-0.0442-0.1390.02960.2306-0.0133
0.18940.13430.27870.1084-0.2773
0.27830.07080.0616-0.1661

Sourse Sarvey date
Note Eigenvalue: CV1; 0.19, CV2; 0.13

The Influence of Agricultural Production Information on the Agricultural Management Scale
In this section, Canonical Correlation Analysis reveals that attribute, crop, and agricultural
production information are related to annual income from arable land and agricultural activities andare considered a result of farm management. The Canonical Correlation Analysis is used to identify
and measure the associations between two sets of variables. The analysis is applicable in the same
way as multiple regression analysis, but it is more suitable when there are multiple objective
variables. Therefore, the objective variables of Canonical Correlation analysis are Y1: cultivatedland and Y2: annual income from agricultural activity. Further, explanatory variables are X1:
gender; X2: age; X3: educational background; X4: rice; X5: vegetables; X6: fruits; X7: information
about seeds; X8: information about machinery; X9: new technology information; X10: information
about chemical fertilizer; X11: information about organic fertilizer; X12: market information; X13:Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

information about training; X14: price information; X15: information about harvest; and X16:
planting information. In Table 3, the results from the estimation of the Canonical Correlation
Analysis are shown in the research site.
According to the results of Canonical Correlation analysis, Canonical variate 1 shows
cultivated land while Canonical variate 2 shows annual income from agricultural activity.
Cultivated land: educational background, rice and fruits are affecting as attributions, andinformation about harvest is affecting as agricultural production information. Therefore, thecultivated land is affected by the index aiming at expanding the scale of rice production. For annual
income from agricultural activity: gender is affecting as attributions, and new technology
information, information about organic fertilizer and training are affecting as agricultural
production information. Therefore, annual income from agricultural activity is affected by an index
of new technology information, information about organic fertilizer and training, all of which areimportant for high-quality crop production. The results of the analysis suggest that the developmentof multiple farming in Cambodia is under the condition of expanding rice production andincreasing the skills of local farmers in agricultural technology.
CONCLUSION
The main object of this study was to quantitatively grasp the relevance among local farmers toanalyze the characteristics of local farming and agricultural production information to build stable
and sustainable farming needed by the farmers in Kampong Cham Province, Cambodia. In addition,a Canonical Correlation Analysis applies to attributions, crops and agricultural production
information are associated with annual income from agricultural activity and cultivated land thatare considered as a result of farm management.
The results of the analysis are summarized as follows. According to the answers fromquestionnaire, it was confirmed that the index of agricultural production information varies
depending on the districts. According to the results of Canonical Correlation analysis, thecultivated land is affected by the index aimed at expanding the scale of rice production. In addition,
annual income from agricultural activity is affected by the index aimed at high-quality crop
production based on new technology information, information about organic fertilizer and training.
As a result of the analysis, it was suggested that for the development of multiple farming in
Cambodia, in addition to the premise of expanding rice production, it is necessary to improve theskills necessary for the conversion of high-quality crop production.
ACKNOWLEDGEMENTS
This work was supported by JSPS KAKENHI Grant Number JP18K05857.
REFERENCES
Matsumoto, H. 1998. A study of repercussion effect of farm guidance business in agricultural cooperatives.
The Review of Agricultural Economics, 54, 75-85.
Ohtake, H. and Aoyagi, K. 1998. Quantitative analysis of the relation between paddy field acreage allotment
and regional structure in the Tohoku District, Japan. Quarterly Journal of Geography, 50 (2), 105-108.
Yagura, K. 2008. Poverty and widening economic disparity in rural Cambodia. Showado, Japan.
Yamada, S., Mihara, M. and Kawabe, K. 2016. Characteristics of transformation of traditional uplandfarming system in Cambodia, A case study of Snuol Commune, Kratie Province. International Journal ofEnvironmental and Rural Development, 7 (2), 81-86.
Yamada, S., Mihara, M. and Kawabe, K. 2017. Characteristics of participants of non-formal education
contributing to learning achievement, A case study of Snuol Commune, Kratie Province, Cambodia.
International Journal of Environmental and Rural Development, 8 (2), 111-116.

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Research article
erd

Moisture Content Prediction of Dried Young Papaya during
Drying and Water Absorption
SOKLY SORM
Graduate School of Agriculture, Tokyo University of Agriculture, Tokyo, JapanYOSHIKI MURAMATSU*
Tokyo University of Agriculture, Tokyo, Japan
Email: y-murama@nodai.ac.jp

MASANORI HASHIGUCHI
Keisoku Engineering System Co., Ltd., Tokyo, JapanDAHAI MI
Keisoku Engineering System Co., Ltd., Tokyo, JapanEIICHIRO SAKAGUCHITokyo University of Agriculture, Tokyo, JapanSHOTARO KAWAKAMITokyo University of Agriculture, Tokyo, Japan
Received 14 January 2021

Accepted 6 December 2021(*Corresponding Author)

Abstract The effective use of agricultural products and the development of processed foods
with guaranteed safety and quality are needed in Kampong Cham Province, Cambodia.
Young papaya is an important agricultural product in this area. Dried young papaya is oneof the preserved foods. The main objective in this paper was to provide basic information
for the optimization of drying process. Two types of young papaya, raw or fresh papaya andblanched young papaya, were used in this study to investigate the influence of drying
pretreatment that is, blanching, on the changes in the moisture content during drying andwater absorption. The hot air-drying characteristics of each sample were measured at threetemperatures (30, 50, and 70°C), three air velocities (1, 2, and 3 m/s), and a relative
humidity of 40%. The examination of the effects of temperature, air velocity, and blanchingon the drying of samples resulted in the drying characteristics of the raw sample being very
similar to that of the blanched sample. A linear relationship existed in the moisture content
range between the initial moisture contents and 500% (d.b.). The exponential model wasapplied to predict the changes in the moisture contents of samples below500% (d.b.) at eachdrying condition. The drying rate constants in the period above or below500% (d.b.) wereincreased with increasing air temperature and air velocity and expressed as a linear functionof both temperature and air velocity, respectively. The water absorption characteristics ofthe dried young papaya and the dried blanched young papaya that were dried after
blanching were investigated at three temperatures (20, 30, and 40°C). Blanching before
drying of the sample had the effect of slowing the water absorption rate. The water
absorption rate constant tended to increase with increasing soaking temperature.
Keywords young papaya, drying characteristics, water absorption characteristics,
blanching, temperature and air velocity dependency,
prediction model of moisture contentⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

INTRODUCTION
The effective use of agricultural products and the development of processed foods with guaranteedsafety and quality are needed in Kampong Cham Province, Cambodia. Young papaya is an
important agricultural product in Kampong Cham. Recently, in Japan, young papaya has beenrecognized as a regional biological resource for the diversification of primary producers into
processing and distribution, and it is cultivated in the Kanto region.
Although young papayas can be eaten fresh, they can also be used after drying. Drying is oneof the oldest preservation methods and does not require special machines or devices in almost allcases. Drying not only increases the shelf life of the product but also increases its food value. Dried
young papaya has been sold as a processed food. Usually, dried young papayas are rehydrated tosome degree before eating. Pretreatments, for example, blanching, are often added to enhance thequality of dried vegetables. Blanching, a mild thermal treatment similar in temperature-time
intensity to pasteurization, is applied to fruits and vegetables primarily to inactivate enzymes thatcatalyse degradation reactions (Park et al., 2014). Lydia et al. (2017) investigated the effects ofpretreatments, including soaking in certain solutions and drying methods, on some qualities ofdried mango fruit.
Some researchers (EI-Aouar et al., 2003; Lagunez-Rivera et al., 2007; Fernando et al., 2008;
Lemus-Mondaca et al., 2009; Udomkun et al., 2015) have measured and analysed the drying
kinetics of papaya. Almost all previous papers have reported the drying characteristics of mature
papaya. However, very few studies have measured the hot air-drying characteristics of young
papaya with different air velocities, as performed in this study. In previous references (EI-Aouar etal., 2003; Lagunez-Rivera et al., 2007; Fernando et al., 2008; Lemus-Mondaca et al., 2009;
Muramatsu et al., 2012; Udomkun et al., 2015), some mathematical models (drying models) wereused to describe the relationship between the moisture content of the sample and drying time.
Optimum drying and water absorption models, including the values of parameters, are particularly
useful for easily predicting the changes in the moisture content of materials. Therefore,
determination of the optimum model is important for practical use.
In this study, we examined the hot air-drying characteristics of two types of young papaya:
raw and blanched young papaya at three different temperatures and air velocities. In addition, thewater absorption (rehydration) characteristics of dried and dried blanched young papaya were alsomeasured at three different temperatures. The results obtained in this study provide important basic
information and are needed to optimize drying processes and to design dryers.
OBJECTIVE
The objectives of this study were 1) to examine the effects of air temperature, air velocity, andblanching treatment on the drying characteristics of the sample, 2) to investigate the influence of
blanching treatment and soaking temperature on the water absorption characteristics of the sample,
3) to derive suitable mathematical drying and water absorption models to describe changes inmoisture content with time, and 4) to obtain empirical equations to express the relationshipbetween the drying or water absorption rate constants and the measurement conditions.
METHODOLOGY
Sample Preparation
Young papaya (Carica papaya) imported from Thailand was purchased at a supermarket in Tokyo,
Japan. Before the test, the young papayas were stored in a refrigerator at approximately 4°C. Afterthe peel was removed from the young papaya, the young papaya was cut into a rectangularparallelepiped (50 mm in depth, 20 mm in width, and 2.5 mm in height) by using a commercial
vegetable cutter. We call this sample the “raw sample” in this manuscript. For the blanchingtreatment, the raw young papayas were immersed in boiling water at 100°C for 30 s and cooled inⒸ ISERD

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cold water at 0°C for 2 min. We describe this sample as the “blanched sample” in this manuscript.
Hot Air-drying Test
The changes in the moisture content of raw and blanched samples using the hot-air drying method
were measured at three temperatures (30, 50, and 70°C), three air velocities (1, 2, and 3 m/s), and a
relative humidity of 40%. A constant temperature and humidity chamber (KCL-2000, EYELA Co.,
Ltd.) was used as a drying chamber in this study to maintain air temperature and humidity during
the drying test. The air velocity was adjusted with a fan (CUDC 12B4, Japan Servo Co., Ltd.)
connected to a DC power source (AD-8735D, A&D Co., Ltd.). A stainless-steel basket (50 mm indepth, 20 mm in width, and 2.5 mm in height with a 3 mm aperture) was utilized as a sample tray.
Approximately 100 g of sample was placed on the sample tray and dried in the drying chamber.
The sample tray was removed out from the drying chamber at a preset time to measure the masschange of the sample. The mass change of the sample was measured with a digital balance (GX4000, A&D Co., Ltd.) and recorded at time intervals every 20 min for the initial 2 h and every 30
min from 2 h until the sample's moisture content became 15% (d.b.). After weighing the sample
mass, the sample tray was quickly returned to the drying chamber. When the moisture content of
the sample reached approximately 15% (d.b.), the mass of dry matter in the sample was determinedusing a forced hot air oven (VTEC-166, Isuzu Seisakusho Co., Ltd.) at 105°C for 24 h. Utilizing
the measured value of the mass of dry matter in the sample, the changes in mass during drying
were converted to changes in the moisture content of the sample.
Measurement of Water Absorption Characteristic
To measure the water absorption characteristics, the raw and blanched samples were dried by the
hot-air drying method at a temperature of 30°C, an air velocity of 3 m/s, and a relative humidity of
40% with a drying apparatus as previously mentioned. We describe the dried sample that wasadded to the blanching treatment before drying as the “dried blanched sample” in this manuscript.
Each dried sample was stored in a polyethylene bag and kept for 5-10 days at room temperature
before the water absorption test to ensure the uniform distribution of moisture in the bag andequilibrate the moisture content of the sample. The moisture content changes of the samples soaked
in water were measured at three different temperatures (20, 30, and 40°C). Approximately 1 g ofsample was immersed in a glass beaker containing 200 ml distilled water in a water bath at a preset
temperature. At time intervals every 1 min for the initial 6 min, 2 min from 6 to 10 min, 5 min from10 to 30 min, and then 30 min from 30-90 min, the sample was removed from the water, and thesurface of the sample was wiped with Kimwipes® (S-200, Nippon Paper Crecia Co., Ltd.) toremove residual liquid. These measurements were conducted until the moisture content of eachsample reached the same moisture content as fresh young papaya (approximately 94% (w.b.)). The
moisture content of the sample after soaking was determined by the oven method (105°C for 24 h).
RESULTS AND DISCUSSION
Hot Air-drying Characteristics
Fig. 1 (a) shows the changes in the moisture content of each sample at an air velocity of 3 m/s and atemperature of 30°C. The moisture contents of both samples decreased linearly with elapsed timefrom the initial moisture content to approximately 500% (d.b.) and decreased, exhibiting a gentle
downward curve below 500% (d.b.). As shown in Fig. 1 (b), the slope of the relationship between
the drying rate and moisture content at each sample was changed at approximately 500% (d.b.). Fig.
1 indicates that the drying characteristics, i.e., changes in the moisture content and drying rate of
the raw sample had almost the same trend as the blanched sample and the hot air-drying process ofboth samples had two periods, i.e., the first and second periods. Similar tendencies were obtainedfor other measurement conditions not shown in Fig. 1.
Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

In the first period (above 500% (d.b.)), the moisture contents decreased linearly with anincrease in elapsed time. Therefore, the measured data at each sample and each measurement
condition were fitted to Eq. (1).

M = −k1t + M 0(1)

where M: the moisture content (% (d.b.)), M0: the initial moisture content (% (d.b.)), k1: the drying
rate constant in the first period (1/min), and t: the drying time (min). The measured value of M0 andthe values of k1 determined by using the least squares method and the root mean square error(RMSE) are shown in Table 1. In the second period (below 500% (d.b.)), because the drying rate
decreased linearly with decreasing moisture content, the following exponential model (Muramatsu
et al., 2012) was used to analyse the changes in moisture content.

M − Me= exp − k2 ( t − tc ) 
500 − M e(2)

where Me: the equilibrium moisture content (% (d.b.)), k2: the drying rate constant in the second
period (1/min), and tc: the drying time at a moisture content of 500% (d.b.) (min). The value of tc in
Eq. (2) was calculated from Eq. (1). The measured drying data in the second period were fitted toEq. (2) using the nonlinear least squares method, and the values of k1 and Me were determined ateach sample and each measurement condition. The values of the parameters and RMSE of Eq. (2)are given in Table 2. The comparisons of the observed moisture contents with the results calculated
from Eqs. (1) and (2) at an air velocity of 3 m/s for the raw sample are shown in Fig. 2. The solidlines in Fig. 2 show the results calculated from Eq. (1) or (2). As shown in Fig. 2, the measured
results matched well with the calculated results. Under all measurement conditions, the changes in
the moisture content of the sample caused by hot air-drying could be estimated by Eqs. (1) and (2).

Fig. 1 Drying curve of each sample at an air velocity of 3 m/s and a temperature of 30°C(a) Changes in moisture content and (b) drying characteristics curves

Fig. 2 Comparisons of observed moisture content changes with the results calculated from(a) Eq. (1) and (b) Eq. (2) at air velocity of 3 m/s for the raw sample during dryingⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Fig. 3 Relationships between the drying rate constants in the first period (above a moisture
content of 500 % (d.b.)) of the raw sample and (a): temperature and (b): air velocity
Table 1 Initial moisture content (M0), drying rate constant in the first period (above 500 %(d.b.)) (k1), and root mean square error (RMSE) of Eq. (1) under each set ofmeasurement conditions
SampleAir velocity(m/s)

Temperature(°C)

M0(% (d.b.))k1(1/min)RMSE(% (d.b.))

30
1525
7.572
19.2
50
1625
12.23
20.9
70
1615
16.03
2.6
2
30
1359
8.909
25.8
50
1253
12.87
14.7
70
1331
17.83
3.0
3
30
1643
13.76
47.0
50
1797
22.63
54.3
70
1800
29.92
20.0
1
30
1926
9.189
27.8
Blanched sample
50
1963
14.35
31.6
70
2008
19.77
10.2
2
30
1807
10.69
63.2
50
1576
15.12
12.9
70
1661
21.51
2.2
3
30
1794
15.31
39.3
50
1896
23.82
47.3
70
2302
37.15
18.1
The values of M0 were measured data. The values of k1 were determined by the least squares method based on themeasured results in the first period (above 500 %(d.b.)). The values of RMSE were calculated from the measured
results and the results calculated from Eq. (1).

Raw sample

1

As shown in Tables 1 and 2, the drying rate constants varied with temperature and air velocity.
Figure 3 represents the temperature and air velocity dependencies of k1 for the raw sample.
Although the values of k1 for both samples were not much difference between 1 m/s and 2 m/s, thevalues of k1 at 2 m/s were higher than that at 1 m/s for each temperature. The first period (above
500% (d.b.)) was considered as the apparent falling drying rate period including the sample
shrinkage, i.e., the constant drying rate period from the measurement results of changes in thesample surface temperature. In the constant drying rate period, the drying or water vaporization ratedepends on the heat transfer coefficient, the thicknesses of boundary layers for temperature and air
velocity, and so on. Since there was not much difference in the values of heat transfer coefficientand the thicknesses of boundary layers between 1 m/s and 2 m/s, the effect of air velocity on thedrying rate in the first period might be weak below 2 m/s. The k1 and k2 of each sample increased
almost linearly with the increase in air velocity at each temperature and the increase in thetemperature at each air velocity. Therefore, we derived the following empirical equation to express
the temperature and air velocity dependencies.

k1 or 2 = aTV + bT + cV + d(3)Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

where T: temperature (°C), V: air velocity (m/s), a, b, c, d: constant. The regression results for Eq.
(3) are shown in Table 3. The solid lines in Fig. 3 are the results calculated from Eq. (3). The k1 andk2 values of each sample were represented as a function of both temperature and air velocity by Eq.
(3).
Table 2 Drying time at a moisture content of 500 % (d.b.) (tc), drying rate constant in thesecond period (below 500 %(d.b.)) (k2), equilibrium moisture content (Me), and root
mean square error (RMSE) of Eq. (2) under each set of measurement conditions
Air velocity(m/s)

SampleTemperature
(°C)

tc
(min)

k2
(1/min)Me(% (d.b.))

RMSE(% (d.b.))30
135
1.224×10-2
16.09
11.2
50
92
2.058×10-2
9.542
14.2
70
70
2.940×10-2
5.132
14.0
2
30
96
1.708×10-2
14.37
12.8
50
59
2.549×10-2
8.183
12.0
70
47
3.649×10-2
5.153
16.2
3
30
83
2.052×10-2
13.36
16.0
50
57
3.438×10-2
8.604
11.8
70
43
5.157×10-2
5.226
16.1
1
30
155
1.136×10-2
13.65
23.0
Blanched sample
501021.845×10-2
5.345
21.9
70
76
2.785×10-2
0.02047
24.5
2
30
122
1.759×10-2
14.63
9.9
50
71
2.302×10-2
5.895
18.8
70
54
3.315×10-2
0.488123.6
33085
1.931×10-2
11.37
18.4
50
59
3.643×10-2
9.005
10.0
70
49
4.249×10-2
5.628
26.7
The values of tc were calculated from Eq. (1) by using the values of M0, k1, and M=500. The values of k2 and Me were
determined by the nonlinear least squares method based on the measured results in the second period (below
500 %(d.b.)). The values of RMSE were calculated from the measured results and the results calculated from Eq. (2).
1

Raw sample

Table 3 Values of the parameters and root mean square error (RMSE) of Eq. (3) for eachdrying rate constant and sample
Drying rate
constant(1/min)k1
k2

Samplea(s/min･°C･m)b(1/min･°C)c(s/min･m)d(1/min)RMSE(1/min)Raw
Blanched
Raw
Blanched

9.626×10-2
1.407×10-1
1.736×10-4
7.535×10-5

8.708×10-2
7.896×10-2
2.163×10-4
3.151×10-4

2.687×10-1-1.541-1.305×10-3
2.234×10-3

1.238
3.613
1.962×10-3-1.735×10-3

2.052
2.469
1.438×10-3
2.251×10-3

The values of a, b, c, and d were determined by the least squares method based on the values of k 1 and k2 shown in Tables
1 and 2. The values of RMSE were calculated from the values of drying rate constant (k 1 or k2) shown in Table 1 or 2 andthe results calculated from Eq. (3).

Water Absorption Characteristics
The moisture content of dried and dried blanched samples increased with the elapsed time,
exhibiting a gentle upward curve from the beginning of soaking at all three temperatures, as shownin Fig. 4. The water absorption rate of dried blanched samples was slower than that of driedsamples at each temperature. The dried blanched sample was harder and had a smaller size than thedried sample. The difference in organizational structure for the samples after drying could becaused by the difference in water absorption characteristics. The exponential model Eq. (4)(Tagawa, et al. 1997) was used to analyse the changes in moisture content from the initial moisture
content of 15% (d.b.).

M − Ms= exp ( − k3tWA )15 − M s(4)Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

where Ms: saturated moisture content (% (d.b.)), k3: water absorption rate constant (1/min), and tWA:soaking time (min). The solid lines and broken lines in Fig. 4 represent the results calculated from
Eq. (4). The values of k3, Ms, and RMSE of Eq. (4) are shown in Table 4.
The k3 of each sample increased with increasing soaking temperature and was related tosoaking temperature by the following Arrhenius equation.

k3 = d  exp − E R (T + 273.15)

(5)

where R: ideal gas constant 8.314 (J/mol･K), d, E: constant. The values of d and E were 6.047×102
and 2.477×105 for the dried sample and 6.444×103 and 3.278×105 for the dried blanched sample,
respectively.
Table 4 Water absorption rate constant (k3), saturated moisture content (Ms),and root mean square error (RMSE) of Eq. (4) for each sample
SampleRaw

Blanched

Temperature
(°C)
20
30
40
20
30
40

k3
(1/min)2.417×10-2
2.994×10-2
4.640×10-2
9.129×10-3
1.499×10-2
2.153×10-2

Ms(% (d.b.))
2572
2748
2525
3549
2999
2696

RMSE
(% (d.b.))
43.8
42.1
37.6
35.0
38.0
59.3

The values of k3 and Ms were determined by the nonlinear least squares method based on the measured
results. The values of RMSE were calculated from the measured results and the results calculated from Eq.
(4).

Fig. 4 Changes in moisture contents during water absorption for each sample
CONCLUSION
The hot-air drying characteristics of two types of young papaya, raw or fresh papaya and blanchedyoung papaya, were measured at three temperatures (30-70°C), three air velocities (1-3 m/s), and a
relative humidity of 40%. The drying characteristics of both samples had almost the same tendency.
The linear function and the exponential model were used to express the changes in the moisture
content of the sample with drying times above or below 500% (d.b.), respectively. The drying rate
constant of each sample and each drying period (above or below 500% (d.b)) increased with anincrease in air temperature and air velocity and was expressed as a linear function of both airtemperature and air velocity, respectively.
The water absorption characteristics of the dried young papaya and the dried blanched young
papaya were measured at three temperatures (20, 30, and 40°C). The water absorption rate of dried
young papaya that did not receive the blanching treatment before drying was faster than that of theⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

sample that was blanched before drying (dried blanched sample). The exponential model could beapplied to explain the water absorption process of both samples. The water absorption rate constantincreased with increasing soaking temperature.
REFERENCES
Adepoju, A.L., Zinash, D. and Osunde, D.Z. 2017. Effect of pretreatments and drying methods on somequalities of dried mango (Mangifera indica) fruit. Agricultural Engineering International, The CIGR ejournal, 19 (191), 187-194.
EI-Aouar, A.A., Azoubel, M.P. and Murr, X.E.F. 2003. Drying kinetics of fresh and osmotically pre-treatedpapaya (Carica papaya L.). Journal of Food Engineering, 59, 85-91.
Fernando, N.J.W., Ahmad, L.A., Shukor, A.R.S. and Lok, H.Y. 2008. A model for constant temperaturedrying rates of case hardened slices of papaya and garlic. Journal of Food Engineering, 88, 229-238.
Lagunez-Rivera, L., Ruiz-Lopez, I.I., Garcia-Alvarado, A.M. and Salgado-Cervantes, A.M. 2007.
Mathematical simulation of the effective diffusivity of water during drying of papaya. Drying
Technology, 25 (10), 1633-1638.
Lemus-Mondaca, R., Betoret, N., Vega-Galvez, A. and Lara-Aravena, E. 2009. Dehydration characteristics
of papaya (Carica pubenscens), determination of equilibrium moisture content and diffusion coefficient.
Journal of Food Engineering, 32 (5), 645-663.
Muramatsu, Y., Sakaguchi, E., Orikasa, T. and Tagawa, A. 2012. Hot air drying and vacuum drying
characteristics of scarlet runner beans. International Journal of Food Engineering, 8 (3), 27.
Park, H.S., Lamsal, P.B. and Balasubramaniam, M.V. 2014. Principles of food processing, food processing,principles and applications (2nd ed.). Wiley and Sons, Ltd, West Sussex, UK.
Tagawa, A., Muramatsu, Y., Kitamura, Y. and Murata, S. 1997. Water absorption characteristics of soybeans
in soaking. Journal of the Japanese Society of Agricultural Machinery, 59 (2), 21-27. (in Japanese)
Udomkun, P., Argyropoulos, D., Nagle, M., Mahayothee, B., Janjai, S. and Muller, J. 2015. Single layer
drying kinetics of papaya amidst vertical and horizontal airflow. LWT - Food Science and Technology,
64, 67-73.

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Research article
erd

Estimates of Factor Shares for Rice Production in Japan for
the Period of 1922-1944
MITSUHIRO TERAUCHI*
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Japan
Email: tera@nodai.ac.jp

SHINOBU YAMADA
Research Center, Institute of Environmental Rehabilitation and Conservation, Tokyo, Japan
Received 20 February 2021

Accepted 6 December 2021(*Corresponding Author)

Abstract The After World War I, the development of the agriculture sector was delayed incontrast with the rapid growth of the industrial sector. Japanese agriculture accelerated byinnovation after the economic revitalization following World War II. It clarifies the
production structure of the rice production in Japan, and there is this study before the end ofWorld War II after the First World War end during the analysis period. This study clarifies
a change of factor shares of the rice production sector in this time. The purpose of this study
is to elucidate the characteristics of the production structure of the rice production in Japan
from 1922 through 1944, and the agriculture in Japan at this time is considered to be in adeveloping stage. The historic change of the rice production in Japan gives a suggestion for
agriculture development in modern Asia. The measurement of factor shares of the riceproduction in the analysis period applies "a method to estimate land income as rest." In
addition, it measures the Cobb-Douglas's type amount of production formation function. It
clarify the contribution of the production input. The changes of factor shares are as follows.
The change of factor shares is land, labor, fertilizer, cost of draft animals, agricultural
machinery, materials, building for agriculture, seed in order of the average value from 1922
through 1944. As for the development of production technological system, it is atechnological innovations land-saving and fertilizer-using. The results of estimate by theamount of production formation function are as follows. In the periods of 1922-1944, theinput of the labor is excess level, the input of the fertilizer is under level and the input of theland is equilibrium level.
Keywords Japan rice production, factor shares, amount of production formation function

INTRODUCTION
World War I, the development of the agriculture sector was delayed in contrast with the rapid
growth of the industrial sector. Japanese agriculture accelerated by innovation after the economic
revitalization following World War II. It clarifies the production structure of the rice production in
Japan, and there is this study before the end of World War II after the First World War end during
the analysis period. It corresponds to the Meiji period and the prewar age of the Showa period, andthis period is a stagnation period of agricultural production. This study clarifies a change of factor
shares of the rice production sector in this time. The purpose of this study is to elucidate thecharacteristics of the production structure of the rice production in Japan from 1922 through 1944,
and the agriculture in Japan at this time is considered to be in a developing stage. The historicchange of the rice production in Japan gives a suggestion for agriculture development in modern
Asia. The measurement of factor shares of the rice production in the analysis period applies "amethod to estimate land income as rest." In addition, it measures the Cobb- Douglas's type amountof production formation function. It clarifies the contribution of the production input.

Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

OBJECTIVE
The main object of this study is to analyze the measurement of factor shares of the rice production.
In analysis, the measurement of factor shares of the rice production applies "a method to estimate
land income as rest." In addition, it measures the Cobb-Douglas's type amount of production
formation function. It clarifies the contribution of the production input. The data applying toanalysis are as follows. Ishibashi 1961. "Teikoku Nokai Kome Seisanhi Cyousa Syusei (Imperial
Agricultural Organization cost of rice production investigation collection)" is from 1922 to 1948
(Natl. Res. Inst. of Agricultural Economics) (Natl. Res. Inst. of Agricultural Economics publication,
the 207th). A period of estimation of factor shares and the amount of production formation function
by estimate is 1922 through 1945. Sample data are thyme series data for 24 years.
METHODOLOGYThe Estimates of Factors Share
The measurement of factor shares of the rice production in the analysis period applies "a method toestimate land income as rest." It is presented by the following:
Factor sharesL＝(PL・L)/(P・Q)(1)

Factor sharesK＝(PK・L)/(P・Q)(2)

Factor sharesV＝(PV・L)/(P・Q)(3)

Factor sharesS＝1-(PL・L)/(P・Q)-(PK・L)/(P・Q)-(PV・L)/(P・Q)(4)where Q is output; P output price; L labor input; K capital input; V fertilizer input; S land input; LPlabor input price; KP capital input price; VP fertilizer input purice and S land input price (Hayami
and Ruttan, 1985).
Amount of Production Formation Function
The function type assumed is the Cobb-Douglas's type production function. The function toestimate is the next formula (Tsuchiya, 1976).
X = Ａ・L＾α・V＾γ・S＾δ
（0 <α, 0 <γ, 0 <δ, α+γ+δ ≒ 1 ）(5)

It is presented by the following:
lnX = lnA+αlnL+γlnV+δlnS+ζ

(6)

where X is output; L labor input; V fertilizer input; S land input.
Examination of the Contribution of the Production Input
The marginal productivity of input X is MPX. P is an output price. PX is X input price. In the caseof ①: MPX> (PX/P), the input of X is under. In the case of ②: MPX = (PX/P), the input of thefactor of production is equilibrium. In the case of ③: MPX <(PX/P), the input of the agent of
production is excess. It is represented by the following. ④ Value of production elasticity of
X>factor shares X. ⑤Value of production elasticity of X= factor shares X. ⑥Value of production
elasticity of X<factor shares X.
Data CollectionⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

As for the data, Miyuki Ishibashi et al,"Imperial Agricultural Organization cost of rice production
investigation collection", the sample data are thyme series data for 24 years. The index to use for
estimation is an unpolished rice yield ("koku"≒140-150kg), product value (Japanese yen), seed
costs, manure costs, wages, material costs, labor force of livestock costs, agricultural machinery
costs, building for agriculture. These variables are numerical value per "tan" (≒10a). The variabledata of the measurement of the amount of production formation function are as follows. Q is theamount of production. Here, it adopted an unpolished rice yield. L is wages. It adopted the total offamily labor and the employment labor. V is an ordinary input. It adopted seed and sapling costs,
manure costs, agriculture drug costs, and the total of material costs. S is rice paddy area. It ismeasured using the variable shown above. The data of the Miyuki Ishibashi great work "Imperial
Agricultural Organization cost of rice production investigation collection" were displayed by a"tan," and therefore it took advantage, and, on the occasion of a measurement, the numerical value
was converted the planted area around one farmhouse. Therefore, the numerical value multiplied
the planted area by it and converted it into numerical value per one farmhouse.
RESULTS AND DISCUSSION
The Development of Rice Production in Japan (1881-2012)
The analysis object period of this study is 1922-1944. In the history of Japanese agriculture, it
confirms a characteristic of this time. A change of the rice production in Japan from 1881 through2012 is shown in the figure. 1881 is standard age (1881 = 1.0). The development of rice productionin Japan for the period of 1881-2012 is shown in Fig. 1.
World War I brought a boom after the war for Japan. By the progress of the industrial division,
the Industrial production value overtook an agricultural production value after the World War I.
The development of the agriculture sector was delayed under the parasitic landlord system incomparison with the rapid development of the industrial sector (Teruoka, 2008). After World War
II, the Japanese economy continued rapid growth during a period from 1955 through 1973 (Higheconomic growth period). In this time, the agriculture sector drastically improved production by the
spread of artificial manure, pesticide, and agricultural machines. However, the consumption of rice
was delayed, so there was overproduction. Therefore, a policy of reducing the rice acreage wasstarted in 1970 (Hayami and Yamada, 1991).
Index: 1981=1. 0
3.5
3
2.5
2
1.5
1
0.5

1881
1885
1890
1895
1900
1905
1910
1915
1920
1925
1930
1935
1940
1945
1950
1955
1960
1965
1970
1975
1980
1985
1990
1995
2000
2005
2010

0

Yea r
rice total a reari ce yi el d 10 per a resri ce tota l y i el dri ce suppl y per ca pi ta

Fig. 1 Development of rice production in Japan (1881-2012)Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

The Change of the Element Input of the Rice Production (1922-1944)
A change of the element input of the rice production from 1922 through 1944 is shown in Fig.
2. In this Figure, the change of the input standard of each agent of production is shown in thestandard in 1922 (1922 = 1.0).
Index: 1922=1. 0
5

4

3

2

1

0
1922 1924 1926 1928 1930 1932 1934 1936 1938 1940 1942 1944
1923 1925 1927 1929 1931 1933 1935 1937 1939 1941 1943

Y ea rri ce yi el dproducti on
a rea

s eed
f erti l iz er
l abormateri a l s
dra f t a nima ls

machinebui l dingFig. 2 The change of the element input of the rice production (1922-1944)
Table 1 Changes in factor shares for rice production in Japan (1922-1944)
Year

seed
fertilizer
labor
（%）
（%）
（%）
①
②
③
1922
0.01470.22500.4618
1923
0.01290.20470.3835
1924
0.01000.16110.3294
1925
0.00810.14100.2265
1926
0.00820.1676
0.2392
1927
0.00800.17870.2306
1928
0.00810.17620.2454
1929
0.00820.1606
0.2421
1930
0.01210.24160.44981931
0.01030.20350.4021
1932
0.00890.15990.34201933
0.00880.17400.3275
1934
0.00810.14970.2992
1935
0.00880.14570.2974
1936
0.00850.14510.2762
1937
0.00950.14550.2633
1938
0.00960.15000.28191939
0.00820.13550.30581940
0.01090.19330.3753
1941
0.01050.17480.3872
1942
0.01070.14170.40491943
0.00950.13280.3571
1944
0.01120.12320.4231
Note： ⑧＝1-(①+②+③+④+⑤+⑥+⑦)

materials（%）④
0.01990.01730.01700.01290.01550.01820.02000.01540.03310.02910.02710.02450.02120.02100.02170.02230.02520.02580.03120.0316
0.0336
0.03150.0440

draft animals（%）⑤
0.0651
0.0561
0.04190.02680.03020.03330.03190.02690.05480.04900.04000.03900.03470.03500.03150.03200.03520.03860.04940.05400.05430.04990.0624machine（%）⑥
0.03140.02860.02100.01840.02610.01940.02060.02020.03740.03590.02960.02950.02600.02550.02480.02630.02830.03030.03610.03770.04080.03930.0549building（%）⑦
0.03410.03180.02590.01590.02040.01900.02000.01960.02930.03120.02630.02540.02320.02120.02080.02040.01930.01850.01980.02360.02400.02410.0296land（%）⑧
0.14800.2651
0.39360.55030.49280.49280.47770.50700.14200.23890.36620.37120.43780.44540.47140.48060.45050.43740.28390.28050.29000.35570.2515The Cange of Fctor Sares of the Rice Poduction (1922-1944)
Table 1 shows the change of factor shares is land, labor, fertilizer, cost of draft animals, agricultural
machinery, materials, building for agriculture, seed in order of the average value from 1922
through 1944. The change of these factor shares becomes land, labor, manure, labor force of
livestock, agricultural machinery, materials, a building, the seed in order of a standard level. FactorⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

share of the capital such as labor force of livestock, agricultural machinery, the building shows a
low value. On the other hand, labor, land and factor share of ordinary input materials such as themanure shows a high value. The period for the analysis was the time when it could not expect the
expansion of the land area. Under such situations, the change of factor shares of the agent of
production shows that the following production engineering system has been developed. As for thedevelopment of production technological system, it is a technological innovations land-saving andfertilizer-using (Sawada, 1991).
The Eamination of the Estimated Result of the Amount of Production Formation Function
The measurement results of the amount of production formation function are as follows.
lnX= +0.0097 +0.1233lnL +0.3609lnV +0.3627lnS(0.0051) (0.4687)(1.4125)(0.5920)
R2 = 0.6030(7)Firstly, the value of A is 0.0097. It is supposed that this suggests the existence of the neutral
technological change. Secondly, the value of α is 0.1233. Thirdly, the value of γ is 0.3609. As forthe fourth, a value of δ is 0.3627. As for the fifth, α+γ+δ is 0.8468, and the values are less than 1. It
is similar to the linear homogeneous production function. This means that the constant returns toscale. This conclusion supports an original hypothesis. In other words, there are not the economies
of scale in this production stage.
Examination of the Contribution of the Production Input
In a C-D's type production function, a value of the production of agent of production X elasticity
and the distribution diagram of agent of production X have a characteristic to be equal. From it, theeconomical analysis of the input standard of the factors of production is possibility. It compares thevalue of the factors of production of factor share and the value of the production elasticity by theestimated result of the C-D's type amount of production formation function. And it adds
economical analysis about the element input standard of each agent of production.
As for the labor input standard, an estimate of the labor (α) for 0.1233, as for the factor shareof the labor are 1922-1930: 0.3120, 1931-1940: 0.3171, 1941-1944: 0.3931 and 1922-1944: 0.3283.
In all periods, the numerical value of factor share is higher than a value of the production of factorsof production elasticity, it is in this way supposed that the quantity of throwing down standard offactors of production is an excessive tendency.
As for the manure input standard, an estimate of the manure (γ) for 0.3609, as for the factor shareof the labor are 1922-1930: 0.1841, 1931-1940: 0.1602, 1941-1944: 0.1431 and 1922-1944: 0.1666.
In all periods, the price of the production of factors of production elasticity is higher than a value offactor shares of factors of production. It is in this way supposed that the quantity of throwing down
standard of factors of production is a too few tendencies.
As for land input standard, an estimate of the land (δ) for 0.3627, as for the factor share of the laborare 1922-1930: 0.3855, 1931-1940: 0.3983, 1941-1944: 0.2944 and 1922-1944: 0.3752.
The period of 1941-1944 years, the price of the production of factors of production elasticity
is higher than a value of factor shares of factors of production. It is supposed that the input standardof factors of production is a too few tendencies. However, in other time, as for the value of the
production of factors of production elasticity, the value of factor share of factors of production isalmost balanced. It is supposed that the input standard of factors of production is balanced.
The results of estimate by the amount of production formation function are as follows. In the
periods of 1922-1944, the input of the labor is excess level, the input of the fertilizer is under level
and the input of the land is equilibrium level.
CONCLUSIONⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

The purpose of this study is to elucidate the characteristics of the production structure of the riceproduction in Japan from 1922 through 1944. The measurement of factor shares of the riceproduction in the analysis period. In addition, it measures the Cobb-Douglas’s type amount of
production formation function. It clarifies the contribution of the production input. The changes offactor shares are as follows. The change of factor shares is land, labor, fertilizer, cost of draft
animals, agricultural machinery, materials, building for agriculture, seed in order of the averagevalue from 1922 through 1944. As for the development of production technological system, it is atechnological innovations land-saving and fertilizer-using. The results of estimate by the amount of
production formation function are as follows. In the periods of 1922-1944, the input of the labor isexcess level, the input of the fertilizer is under level and the input of the land is equilibrium level.
As a result of analysis, for the increase of the agricultural production, it was suggested that thedevelopment of the technique to reduce the limitation of the factor of production was important.
The development of the agriculture section is important in economic development in modern Asia.
When it thinks about a strategy of the agriculture development in modern Asia, it is suggested that
it is necessary to consider the direction of the change of the production technique.
REFERENCES
Hayami, Y. and Vernon, W.R. 1985. Agricultural development: An international perspective. Johns Hopkins
University Press, 506, 204-205.
Hayami, Y. and Yamada, S. 1991. The agricultural development of Japan, A century's perspective.
University of Tokyo Press, 276, 13-108.
Ishibashi, Y. 1961. Teikoku nokai kome seisanhi cyousa syusei. Imperial Agricultural Organization Cost of
Rice Production Investigation Collection, (in Japanese).
Sawada, S. 1991. Technological progress in Japanese agriculture. Association of Agriculture and Forestry
Staistics, 364, 331-364.
Teruoka, S. 2008. Agriculture in the modernization of Japan 1850-2000. Ajay Kumar Jain for Manohar
Publishers and Distributors, 375, 127-154.
Tsuchiya, K. 1976. Productivity and technological progress in Japanese agriculture. University of Tokyo
Press, 261, 40-70.

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Research article
erd

Perspective on Urban and Peri-Urban Agriculture in
Cambodia’s Capital: Phnom Penh
CHES SOPHY*
Graduate School of Frontier Sciences, University of Tokyo, Japan
Email: sophy_ches257@yahoo.com

EIJI YAMAJI
Graduate School of Frontier Sciences, University of Tokyo, Japan

THOL DINA
Ministry of Land Management, Urban Planning and Construction, Cambodia
Received 30 January 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract Due to population growth and urbanization over two decades, Phnom Penh
Capital’s area has almost doubled from 375 square kilometer in 2001 to 692.46 square
kilometer in 2019. Meanwhile, the number of farmers declined from 36.77% of the
population in 2001 to 10% in 2015. Respecting these issues, the government of Cambodia
prepared the Land use master plan of Phnom Penh City 2035. However, no clear
implementation of the plan and the fast growth of construction have become the mainconcerns of international donors. Moreover, the integration of Phnom Penh with some areasof neighboring provinces will affect agricultural activities. Therefore, this research aims toascertain more details of agricultural land use in Phnom Penh by responding to the Master
Plan and to explain the current activities of urban agriculture or peri-urban agriculture in thecapital. Owing to the pandemic, this research was conducted by solely reviewing andanalyzing legal documents, reports from the government and donors, and other reliable
sources. The Land use master plan clearly indicates the space reserved for the peri-urban
agricultural activities; however, there are no details regarding agricultural policy dealing
with the space reserved for peri-urban agriculture. The involvement of the Ministry ofAgriculture, Forestry and Fisheries is also not explained. Based on the reports from donors
and NGOs, lack of roles and responsibilities, limited capacity and limited finance havebecome the main concerns for the government regarding implementation of the Master Plan.
Importantly, current rapid growth of construction does not pay any attention to thedevelopment of city plans. Housing complex projects have increased from 77 in 2011 to
178 projects in 2019. Some private businesses are practicing peri-urban agriculture on theoutskirts of the capital by growing, selling some vegetables, and providing the space for therelaxation.
Keywords urban agriculture, peri-urban agriculture, agricultural policies,
land use master plan

INTRODUCTION
Phnom Penh, the capital of Cambodia, is located in South-East Asia. All main activities including
economics, politics, culture and diplomacy are centered in the capital which has the highest densityof population 2,143,591 in 2021 based on the World Population Review. Phnom Penh covers thearea of 692.46 square kilometer; consisting of 14 districts. Currently, Phnom Penh has expanded byintegrating 20 other communes from neighboring province due to rapid population growth andurbanization. Back in 2001 Phnom Penh covered 375 square kilometers consisting of 70% forhuman settlement, 21% for agricultural activities, 8% covered by water, and remaining not in use(Em and Paule, 2005). The practice of urban agriculture did exist in the capital; however, thenumber of farmers declined from 36.77% of tge population in the capital in 2001 (Em and Paule,Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

2005) to only 10% in 2015 based on the World Bank Group on Urban Development in Phnom Penh(2017). With respect to rapid growth of urbanization and population, the Government of Cambodia
has prepared the Land use master plan of Phnom Penh City 2035. However, no clear
implementation of the plan and the fast growth of construction have become the main concerns ofinternational donors. Moreover, the integration of Phnom Penh with some areas of neighboring
provinces will affect agricultural activities. Therefore, this research aims to ascertain more detailsof agricultural land use in Phnom Penh by responding to the Master Plan; and to explain the current
activities of urban agriculture or peri-urban agriculture in the capital.
METHODOLOGY
Owing to the pandemic, the study was conducted by solely reviewing and analyzing legal
documents, reports from the government and donors, and other reliable sources.
RESULTS AND DISCUSSION
Land Use Pattern in Phnom Penh
Official data on two new integrated districts (Kambo and Boeung Keng Kang) in Phnom Penh is
not available. Fig. 1 shows the administrative boundary of Phnom Penh with only 12 districts.
Among the 14 districts, Chraoy Chongvar, Dangkao, Kambo, Mean Chey, Praek Phnov, Pur
Senchey and Sensokh are considered to be the outskirt areas of the capital (Realestate, 2021).

Fig. 1 Phnom Penh administrative map
Urban Agriculture in Phnom Penh
Decades ago, according to Khmer (2007), most of people living in Phnom Penh did not practiceagricultural activities even despite of potential agricultural land. At that time, there were only a few
NGOs working on urban and peri-urban agriculture. At the present time, core areas of Phnom Penh
have been occupied by economic activities. Based on the data from Phnom Penh’s Department ofAgriculture, Forestry and Fisheries in 2019, some districts on the outskirts of Phnom Penh are used
for growing rice and then for growing vegetables after the rice harvesting season.

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Table 1 Agricultural land in Phnom Penh
DistrictPraek Pnov
Chraoy Chongvar
Chbar Ampov
Saen Sokh
Dangkao
Pur Senchey
Kambo

Rice Growing Area
(ha)
1,409
152
6
247
3,273
310
3,048

Ownership
(ha)
1,372
75
6
217
2,247
80
1,996

Rent
(ha)
37
87
30
1,026
230
1,052

Source: Phnom Penh Department of Agriculture, Forestry and Fisheries (2019)Land Use Master Plan for Phnom Penh Capital 2035
Because there is no clear land use pattern in Phnom Penh for the current situation and to deal withthe rapid growth of population and urbanization, the government of Cambodia has prepared theLand use master plan of Phnom Penh Capital 2035. The main objectives of the master plan are todevelop Phnom Penh to become a core center for development, an international standard city, areserve for the development of necessary physical infrastructure, a metropolitan city and a special
area for cultural heritage. Fig. 2 shows the map of the land use master plan of Phnom Penh capital
2035.
Protected Areas

LegendBuilding Density
Areas with high population density
Areas with high population, buildings along the roads
Areas with much urbanization
Areas with less urbanization

1. Natural and Agricultural Areas
Areas with low population density
Peri-urban Agriculture Areas
Joint Park Areas and Recreational Buildings
2. Archeological Areas
Archeological Areas
3. Protected River bank Areas
vulnerable river bank areas, urbanization and soft buildingsRoad Networks
60m-Width Belt Roads for traffic diversion
30-50m-Width Main Roads
20-30m-Width maind roads in Districts and communes
Main Axis and aligned plants
Transport and Goods

Public Building
Reserved land for big public buildings
Old ancient buildings
Economic Development Zones
PagodasDrainage System
Waste Water reseviors and biological purification areas
Waste water (drainage) canal systems needed to be established
Main Drainage systems
Secondary Drainage systems
Reserved Ponds

Goods Preparation zones and Warehouses
Train station, airports and ports
Ports for tourist ships or boats
Existing Railways
Administrative borders of Phnom Penh City
To-be-studied Areas
Poles
Pu
Ps
Pc
Pl
Pla
Pa
Pe
Pb
Pr
Pi
Pn

University Poles
Sport Poles
Cultural Poles
Pleasure Poles
Exposure tree planting areas and conservation
Administrative Poles
Environmental and Agricultural Poles
Business Poles
Research Poles
Advanced Industrial Poles
National Identifcation Demonstration Poles

Goods
Ld
Ll
Lm
Lf
Lp
Fn
R

Landfill
Biological water purification ponds
Wholesale (Lump sum) Markets
Goods Areas
Goods Storing Areas
National Railway Stations
Bus Station

Fig. 2 Map of land use master plan of Phnom Penh capital 2035
Legend of the map was written in the Khmer language. The English-translated legend wasprovided next to the map. The second green symbol in the legend was used to indicate the spacereserved for the peri-urban agriculture in Phnom Penh Capital.
In order to make the land use master plan realized and vitalized, the Phnom Penh sustainable
city plan was designed to support the implementation of the Phnom Penh master plan for land use
2035. Fig. 3 shows the link between Land use master plan for Phnom Penh 2035 and the Phnom
Penh sustainable city plan 2018-2030.
After obtaining the details of both the land use master plan and the Phnom Penh sustainable
city plan, the study found that there is no clear explanation nor detail regarding the usage ofreserved spaces for peri-urban agriculture as mentioned clearly in the map (referred to Fig. 2).
Noticeably, there are also no details regarding the agricultural policies dealing with green spaces orspace reserved for peri-urban agriculture in the land use master plan. In addition, the involvementof the Ministry of Agriculture, Forestry and Fisheries (MAFF) or other institutes is not mentioned
nor indicated.

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

LAND USE MASTER PLAN FOR PHNOM PENH 2035

Vision: Phnom Penh is a competitive political, economic, business and cultural
center of Cambodia with sustainable and equitable development

URBAN TRANSPORT MASTER
PLAN 2035

PHNOM PENH MASTER PLAN
FOR DRAINAGE AND SEWRAGE
2035

Goal: To solve the current transport
problems/issues and support the 2035 Urban
Vision and Urban Structure

Goal: To improve sewerage treatment anddrainage management in the metropolitan areaof Phnom Penh

PHNOM PENH SUSTAINABLE CITY PLAN 2018-2030
Vision: By 2030, Phnom Penh will become a clean, green and competitive city,
offering a safe and quality lifestyle to its residents.
Goals:- De-couple economic growth from environmental impacts- Increase social inclusion, reduce poverty levels, and improve urban welfare- Provide urban resilience for all citizens to natural, climatic and other risks- Ensure urban competitiveness and attractiveness to businesses

Fig. 3 Link between land use master plan for Phnom Penh 2035
and the Phnom Penh sustainable city plan 2018-2030
Source: Global Green Growth Institute (2019)

These challenges over the implementation of the master plan are a major concern. The WorldBank also shares this concern over the lack of roles and responsibilities for the implementation ofMaster Plan, limited capacity and limited finance (World Bank Group, 2017).
Responding to the rapid growth of housing construction and other building complexes overthe Phnom Penh Capital’s areas, the World Bank also has raised this matter in the report (WorldBank Group, 2017) and pointed out that this development in housing complex has neglected theLand use master plan; it seems that the real estate companies or construction companies do notfollow the land use pattern that has been determined in the Master Plan. The housing complex
projects have increased from 77 (Phnom Penh Capital Hall, 2011) to 178 projects in 2019 (The
Phnom Penh Post, 2019).
Regarding the matter mentioned above, there is also a concern over the process on providing
construction licenses to those real estate companies. All of these affect the land use pattern in
Phnom Penh. It can be assumed that peri-urban agriculture has been affected by the rapid growth ofurbanization and construction in the capital.
Urban Agricultural Policies
All agricultural policies and administration are under the responsibilities of and managed by MAFF.
The overall goal of policy firmly focuses on increasing skills and knowledge, productivity,
diversification, processing capacity, storage, distribution and marketing (Open Development
Cambodia, 2016). Referred to the same source, the government has aimed for agribusiness to makeup 30% of GDP (Gross Domestic Product) by 2025.
To achieve the goals or aims set by the government, there are several main agricultural
policies established. Those policies are as follows:Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

- Cambodia Industrial Development Policy 2015-2025: This policy prioritizes the agriculturaldevelopment as the key element. There are four prioritized developments to be achieved:
development of the agro-industry, development of small and medium enterprises, developmentof transport and logistics, and development of skills training and worker development.
- Agricultural Extension Policy: The main goal of this policy is to ensure that knowledge andtechnology will be accessible to farming communities in order to increase the productivity.
- Crop-Specific Policy: This policy consists of other two main policies: Policy on the Promotionof Paddy Production and Rice Export; and Cambodia Natural Rubber Development Strategy
2011-2020.
There is no specific policy on urban and peri-urban agriculture in the capital; also data on
agricultural activities is very limited. It can be assumed that the government has turned theirattention to other main sectors that are currently growing very fast in the capital. However, there
are some newly developed recreational places or resorts run by private sectors. Those activities
include the growing of organic vegetables and fruit. The details will be explained below.
Urban and Peri-Urban Agricultural Activities
Urbanization and economic development in the capital have caused lifestyle changes. People livingin the capital spend their weekends with family at private resorts or recreational places on theoutskirts of the capital. Those resorts normally serve food and sell organic vegetables grown bythem.
One of the popular places in this sector in Phnom Penh is Amarak Farm also known as
Amarak Veggie Store, established in 2008, located at Koh Krobey Village, Prekthey Commune,
Chbar Ampoeu District. It is about a one-hour drive by car from central Phnom Penh.

Fig. 4 Location of Amarak Farm

Fig. 5 Vegetable cultivation at the farm

Source: www.amarakfarm.com; and www.google.com/map

Fig. 6 Location of Romdoul Reak Reay Farm

Fig. 7 Vegetable cultivation at the farm

Source: https://www.facebook.com/romdoulreakreay/photos/?ref=page_internal; and www.google.com/map

Based on the information on its homepage (www.amarakfarm.com), Amarak Veggie Store
grows various kinds of salad and lettuce, herbs and fruits. The harvest is sent to local markets in
Phnom Penh to sell as fresh and organic products. Besides, the vegetable production, AmarakⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Veggie Store also provides other activities including camping, meeting places (or retreat centers),
wedding receptions, picnics and other outdoor activities because this farm occupies a large area.
Going far to the Northern part of the capital, there is another resort called Romdoul Reak Reay
Farm located in Chraoy Chongvar District. This farm occupies a large area, serves the food andgrows various vegetables to sell at their place. This farm started a few years ago before thepandemic. However, they have extended their activities and diversified the farm.
Urban and peri-urban agricultural practice is active in the capital. Currently, there are many
newly developed resorts or farms. However, there is no official data recorded about these activities.
CONCLUSION
During this transitional development of Phnom Penh due to rapid population growth andurbanization, Phnom Penh has expanded, and the construction of housing complexes and otherbuildings has increased. The government needs to pay more attention to implementing the plan tomake the Land use master plan of Phnom Penh vitalized. Even data on urban and peri-urban
agriculture in the capital is limited. Peri-urban agriculture in Phnom Penh Capital has been actively
practiced as part of resort activities in the outer or outskirt districts. From this viewpoint, without
proper implementation of the Land use master plan and management of the development ofconstruction, reserved spaces for peri-urban agriculture in Phnom Penh capital will be affected.
ACKNOWLEDGEMENTS
The author is deeply grateful to Japanese KAKENHI project on comparative study on agriculturalland use and formation of land use order in urban fringe of Southeast Asian Countries forsupporting this study. Big thanks are given to Mr. Gordon Beal for kindly helping editing this paper.
REFERENCES
Global Green Growth Institute. 2019. Phnom Penh Sustainable city plan 2018-2030. Retrieved fromhttps://gggi.org/site/assets/uploads/2019/06/SUBSTAINABLE-CITY-REPORT_EN_FA3.pdf
Huy, E. and Moustier, P. 2005. Baseline characterization of urban and peri-urban vegetable production in
Phnom Penh. Retrieved from https://agritrop.cirad.fr/544873/1/document_544873.pdf
Khmer, S. 2007. Urban and peri-urban agriculture: Towards a better understanding of low-income producers’organizations. Phnom Penh city case study report, Retrieved from https://faoidrc.files.wordpress.com/2007/08/phnompenh-case-study.pdf
Open Development Cambodia. 2016. Agricultural policy and administration. Retrieved from https://
opendevelopmentcambodia.net/topics/agricultural-policy-and-administration/
Phnom Penh Capital Hall. 2011. Notable data. Retrieved from https://phnompenh.gov.kh/en/phnom-penhcity/facts/notable-data/
Phnom Penh Post. 2019. Experts: Borey projects set to expand beyond Sen Sok. Retrieved from https://www.
phnompenhpost.com/post-property/experts-borey-projects-set-expand-beyond-sen-sok
Realestate.com.kh. 2014. Overview of the districts in Phnom Penh. Retrieved from https://www.realestate.
com.kh/guides/overview-of-districts-in-phnom-penh/
World Bank Group. 2017. Urban development in Phnom Penh. Retrieved from https://openknowledge.
worldbank.org/handle/10986/28958
World Population Review. 2021. Retrieved from https://worldpopulationreveiew.com/world-cities/phnompenh-populationⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Research article
erd

The Dynamics of Social Interactions of Children Playing
around Rural Rivers in Japan
MASAYUKI NITTA*
Department of Civil and Environmental Engineering, Toyo University, Kawagoe, Japan
Email: nitta061@toyo.jp

YOSHIKI KUWABARA
Faculty of Agriculture, Yamagata University, Tsuruoka, Japan

MASAHIRO NAKAJIMA
Institute of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Japan
Received 19 February 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract In Monsoon Asia countries, rivers have intimate bonds with rural communities,
which create diverse social interactions regarding community building such as recreation,
education, and tourism. Especially, children tend to play around rivers, which is considered
as one of the foundations of community building since playing fosters children’s placeattachment to the local rivers. However, the number of children playing around rivers has
been decreasing owing to expanding urbanization. This study aims to reveal 1) the
influences of river use by family members and neighborhoods on children’s river play, 2)
the dynamics of children’s social interactions in playing around rivers, and 3) the
emergence mechanisms of children’s social interactions in the play places. Questionnaire
survey (127 local children from 9 to 11 years old), participatory observation, and hiring
survey (49 local children from 9 to 11 years old) were conducted in the town of
Gujohachiman, the Gifu Prefecture, Japan. Social network analysis (SNA) was applied tothe observation data to examine the dynamics of social interactions in playing. As a result,river play frequency and preference of children were positively related to the frequency ofdaily use of rivers by their family members and neighborhoods. SNA showed that theinteraction density of children playing around the river gradually increased while repeatedly
fluctuating up and down. This dynamical change of interactions was caused by several
leaders. The two factors for the emergence of children’s social interactions were identified:introducing by the playgroup members and playing with caregivers. These results imply
that rural rivers have the function for children to expand their local interpersonal
relationships through playing, which are supported by local communities. Furthermore,children’s play places around rivers have the potential to become the social interface forrural and urban communities.
Keywords rural rivers, children, play places, social interactions, social network analysis,
environmental education

INTRODUCTION
In Monsoon Asia countries, rivers have intimate bonds with rural communities, which create
diverse social interactions regarding community building such as recreation, education, and tourism.
Especially, children tend to play around rivers (Senda, 1982; Kinoshita, 1992). However, children’swater play around rivers has been decreasing owing to expanding urbanization.
As described in the Convention on the Rights of the Child, an outdoor play of children isessential for their sound development and it is required that the local communities support
children’s outdoor play towards sustainable community building in terms of their well-being.
Various effects have been pointed out for nature play, including river play, such as emotional
stability of children (Yoshinaga et al., 2006), improvement of athletic ability and intellectual abilityⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

(Nakamura, 1999), an increase of independence (Kako, 2009), etc. Also, it is reported that playing
around rivers is effective in improving children's spatial cognitive ability (Onishi, 2000), deepening
their cognitive ability to living organisms (Ohgoshi et al., 2002; Ohgoshi et al., 2003), andimproving children’s social ability through interpersonal interactions (Sato and Takahashi, 2002;
Sato et al., 2004; Enomoto and Nakamichi, 2021). In addition, river play fosters children’s placeattachment to the local rivers, which leads them to nature conservation in the future (Satake andKamihogi, 2006). Therefore, river play is important not only for community development but also
for the conservation of river environments. So far, various studies have been conducted on thephysical structure and biological environments that support children's river play (Fujiwara andMaekawa, 2003; Osawa, 2005; Terauchi et al., 2006; Horiuchi et al., 2009; Kakudo and Nishiyama,
2009; Imanishi and Matsumoto, 2016; Hasegawa et al., 2017).
However, there is no study that examines children's playing in the river from a social aspect
and clarifies the dynamics of human interaction. It is important to quantitatively grasp the social
interactions of children and to examine the relationships between children's river play and the local
community, in order to conserve the children's river play in the future.
OBJECTIVE
The objectives of this study are to reveal 1) the influences of river use by family members andneighborhoods on children’s river play, 2) the dynamics of children’s social interactions in playing
around rivers, and 3) the emergence mechanisms of children’s social interactions in the play places.
METHODOLOGY
Study Area
The study was conducted in the Hachiman district of Gujo city (hereinafter called“Gujohachiman”), which is a rural area located in the middle of the Gifu prefecture, Japan (Fig. 1).
The east, west, and north side of Gujohachiman are adjacent to the mountainous area, and theresidential area is formed along the Yoshida River, which is an upper branch of the Nagara River.
The area is also well known as “Water Town” since the water sources such as springs and wells
have been maintained collectively by local communities in history.
Gifu Prefecture

Study Area

Fig. 1 Location of study
area

Fig. 2 The play places in the rivers in Gujohachiman

In the area, the river play of children was conserved as local culture. The local children playwith water mainly in three places around rivers: Kodara place, Shinbashi place, and Gakkobashi
place (Fig. 2). The three places are recognized as “play places” by the residents. Especially
Shinbashi place is a popular sightseeing spot of Gujohachiman for urban tourists, because the place
is known as “jumping spot,” where children jump by the top of the Shinbashi bridge (12m aboveⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

water surface) into the Yoshida River. This place has been designated as one of the 100
Soundscapes of Japan by the Ministry of the Environment since 1996.
Data Collection
In order to collect the data for objective 1, Questionnaire survey was conducted to 127 students,
who are in 4th to 6th grade (aged 9 to 11 years old) at the local primary school, on 15 September,2010 (Table 1). The questionnaire survey was conducted at the integrated study classes. Duringchildren answered the questions, the teachers supervised them to secure the reliability of theanswers. The response rate was 100%. The respondents answered the 18 questions regarding daily
river play around rivers. In this paper, the results of 7 questions out of 18 questions were used: thepreference and frequency of river play (2 items), the living environments (3 items), social
interactions at playing with water (4 items). After the questionnaire, we conducted supplementary
hiring to twelve children regarding to their river play.
Table 1 Respondents of questionnaire survey (n=127)
Sex
Boys
Girls
Subtotal

Grade
5th
16
16
32

4th
22
20
42

6th
27
26
53

In order to collect the data for objectives 2 and 3, observation and hiring survey wereconducted on 29 local children from 9 to 11 years old from the 3rd to 5th September. The subjectsof the survey were selected by those who answered the questionnaire. During the children playing
around the three water play places, investigators recorded the number of children, the playing
behavior of each child, and the playing location with one-minute intervals until all children left theplay places. After the all children left the play places, the investigators conducted open-endedgroup interviews to them. The interview consists of the following questions:
Where do you play with water around rivers usually?

Why do you play there?
Have you ever played with an infant or adult, who you did not know before?
Analysis
In order to analyze the relationships between the preference and the frequency of children’s river
play and their living environments (objective 1), simple tabulation and cross-tabulation wereconducted on the data obtained by questionnaire survey. Secondly, the p-value was calculatedusing the results of cross-tabulation. These computations were done using the SPSS program,version 10.0.
As for objective 2, Social Network Analysis (hereinafter called “SNA”) was applied to theobservation data (Freeman, 2004; Nooy et al., 2012). The dynamics of children’s social networks
were analyzed by using density, which is an index of SNA. The density is calculated by using Eq.
(1) as follows:
(1)
Where
Di: Density of children’s social networks at the time ini: The number of children existing in the play places at the time i
mi: The number of children’s ties at the time iⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Density (Di) is an index of how close the social interchange between children playing in theplay places at the time i is. If the density is high, the children make relatively large groups to play
together. If the density is low, children play individually or in small groups.
As for objective 3, how children become acquainted with another child, infant or adult was
analyzed based on the observation data. Focusing on the matter of how the children’scommunication started, the emergence mechanisms of children’s social relationships in the playplaces were classified by the acquaintances’ attributes: child, infant, and adult.
RESULTS AND DISCUSSION
Status of River Use of Children
Table 2 shows the preference and the frequency of river play of the subjects by sex. The ratio of
those who prefer river play was 91.3% in total. As a result of chi-square analysis, the ratio of boys,
who prefer river play (96.9%) was significantly higher than the ratio of girls (85.5%, p < 0.05). As
for the frequency of river play, the ratio of those who play with water more than once a week was
50.4% in total. As a result of chi-square analysis, the ratio of boys, who play with water more thanonce a week (67.7%), was significantly higher than the ratio of girls (32.3%, p < 0.001). Water playaround rivers was generally preferred by many children. In particular, it was found that boys tended
to prefer playing around rivers.
Table 2 Children’s preference and frequency of water play around rivers by sex
The number of children by theirpreference of river play (“prefer” vs“not prefer”) and its ratio*
Prefer
Not prefer

The number of children by their frequency of river play(“once a weelk or more” vs “less than once a week”) and
its ratio***
Once a week or more
Less than once a week

Boys (n=65)

63 (96.9%)

2 (3.1%)44 (67.7%)

21 (32.3%)

Girls (n=62)

53 (85.5%)

8 (14.5%)

22 (36.1%)

42 (67.7%)

Subtotal (n=127)

116 (91.3%)
11 (8.7%)
64 (50.4%)
63 (49.6%)
Significant difference is indicated by *p < 0.05, **p < 0.01, and ***p < 0.001, determined by chi-square test.

Table 3 Relationship between the experiences to get to know new persons during
river play and the number of members of river play
The experience of children to getting to know
new persons during river play

The number of children by the number of members to play witharound the river*With 1 or 2 members
With more than 3 members

Yes, I had experiences to getting to know new
31
36
persons during river play
No, I had no experience getting to know new
39
19
persons during river play
Significant difference is indicated by *p < 0.05, **p < 0.01, and ***p < 0.001, determined by chi-square test.

As for the number of members to play with around rivers, all children answered “playing withsomeone (friends or caregivers)”, which means no one played alone around rivers. As for theexperiences of children to getting to know new person during river play, 53.6% of the children(n=127) had experiences to getting to know new person during river play. Table 3 shows therelationship between the experiences to get to know new persons during river play and the numberof members of river play. As a result of chi-square analysis, the children, who play with more than
three members, tended to have the experiences to get to know new persons during river play,compared to the children, who play with two or three members (p < 0.05).
Table 4 shows the relationships between the daily river use of family members and neighbors
and children’s preference and frequency of river play. The children, whose family members andneighbors used the river in daily life, tended to prefer river play (95.5%), compared to those whosefamily members and neighbors did not use the river in daily life (86.9%, p < 0.05). Further, lookingⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

at the frequency of playing in the river, 63.6% of children, whose family members and neighbors
used the river in daily life, answered that they played around the river for a week or more. On theother hand, the ratio of children, whose family members and neighbors did not use the river in daily
life, was 36.9%, significantly lower than that of children whose family members and neighbors
used the river in daily life (p < 0.001). Regarding this result, there were several opinions fromeleven children such as:“Since I was baby, my grandfather (or grandmother, uncle, aunt) went to rivers and played
together with me and he (or she) told me how to play around rivers”.
In addition, there were opinions from eight caregivers such as:“Because we all local residents played around rivers during childhood, so we know thatplaying with water is very fun and it is very important for child development”.
Thus, it is concluded that the daily use of rivers by family members and neighbors had apositive effect on children's preference and frequency of river play, and the children’s river play
was supported by the adults at home and in the neighborhoods.
Table 4 Relationships between daily river use of the family members and the neighbors andthe children’s preference and frequency of river play
The number of children by their The number of children by their frequency
preference of river play of river play (“once a weelk or more” vs(“prefer” vs “not prefer”) and its “less than once a week”) and its ratio***ratio*
Less than once
Prefer
Not prefer
Once a week or more
a weekSomeone of the family members
and neighbors uses the rivers in
63 (95.5%)
3 (4.5%)42 (63.6%)
24 (36.4%)
daily life (n=66)
None of the family members andneighbors use the rivers in daily
53 (86.9%)
8 (13.1%)
22 (36.1%)
39 (63.9%)
life (n=61)
Significant difference is indicated by *p < 0.05, **p < 0.01, and ***p < 0.001, determined by chi-square test.

Dynamics of Children’s Social Interactions in Playing Around Rivers
Fig. 3 shows the dynamics of the social interactions of 21 children played at the Gakkobashi placefrom 16:25 to 17:34. The density of the social interactions went up and down over time, whichmeans that children were playing while repeating gathering and dispersion. The interaction
networks of the children at each time from 16:40 to 17:10 are illustrated in Fig. 4. The black circle
with the alphabet indicates the individuals of the children (ID: from “a” to “u”) and the lines showthat they had interactions, which means playing together.
25

0.80

15

0.60

10

0.40

5

0.20

0
16:25 16:30 16:35 16:40 16:45 16:50 16:55 17:00 17:05 17:10 17:15 17:20 17:25 17:30

0.00

Density

Number of children

20

1.00

Number of children
DensityFig. 3 Dynamics of children’s social interactions in playing at the Gakkobashi placeⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1a) Interaction network of children at 16:40b) Interaction network of children at 16:45

c) Interaction network of children at 16:47

d) Interaction network of children at 16:50e) Interaction network of children at 16:52

f) Interaction network of children at 17:06

g) Interaction network of children at 17:07h) Interaction network of children at 17:10

Fig. 4 Interaction network of children in the river playing at each time from 16:40 to 17:10
At 16:40, twelve children were playing and four playgroups were formed (Fig. 4a), and thedensity at this time was 0.21 (Fig. 3). Then, at 16:45, the playgroups changed, forming a bigger
group of eight children and two pairs (Fig. 4b), and the density was 0.45. Further, at 16:47 childⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1“d” started playing alone, so the group was dispersed (Fig.4c), and the density was decreased at
0.34. At 16:50, the two pairs (child ID: a, g, l, k) started playing with a group of seven children,
forming a large playgroup of 11 children (Fig. 4d), and the density increased at 0.83. Then, again,
the children were dispersed and the group was divided into four groups at 16:52 (Fig. 4e), and thedensity was 0.32 at this time. At 17:06, six new children appeared and started group play (Fig. 4f)
and the density was decreased at 0.30. At 17:07, as the two playgroups merged (Fig. 4g), thedensity increased at 0.75. Finally, the children formed two big groups to play and the density was
1.00 at 17:10 (Fig. 4h).
In this way, the children played while repeating gathering and dispersion, forming a larger
playgroup. Fig. 5 shows the integrated diagram of the interaction networks between 21 childrenthat occurred from 16:25 to 17:34. The thickness of the tie indicates the length of time to play with,and the longer the time, the thicker the tie. The ties between child b, d, h, i were very thick. These
children were the leaders among the playgroups. For example, they decided what kind of play andwhere to play next. Therefore, it can be said that the daily relationships of the children wereexpressed by quantifying the interactions among them that changed over time during river play.
In this section, it was found that the children gradually expanded their playgroups as they
repeatedly gathered and dispersed during river play.

Fig. 5 Integrated interaction networks of 21 children observed from 16:25 to 17:34
Factors for The Emergence of Children’s Social Interactions
Through the observation survey and hiring survey, two factors for the emergence of children’ssocial interactions were identified: (1) introducing by playgroup members and (2) playing withcaregivers.
(1) Introducing by playgroup members: From the results in the previous section, it was foundthat children gradually expanded their playgroups as they repeatedly gathered and dispersed during
river play. Regarding this social interaction processes, the following opinions were given by thethree children who were playing:“We all (local children) play usually in the three play places (Gakkobashi, Shinbashi, andKodara place). So local children playing with water around the rivers have many chances to knoweach other very well.”In addition, the following oral data were obtained from the four children:Ⓒ ISERD

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“When we find some friends in other playgroups during river play, we play together with allgroup members via the friends.”
Therefore, it can be said that there was a social exchange process by introducing to playgroupmembers. This process is modeled in Fig. 6. In the Gujohachiman, children's play places in rivers
are fixed, so children's playgroups appeared in close proximity when playing in the river. At thistime, when groups 1 and 2 appeared, if the member “a” and “b” were acquainted, they first left thegroup and had a conversation (Fig. 6). This formed a small play subgroup. Then, the children “a”
and “b” were invited to play together in each playgroup, and all of them played together to form alarge playgroup. Then, everyone became friends through river play together.
In this way, the cases that social interactions occurred through an introduction by playgroupmembers were observed 17 times during the observation survey. The reason why the children's
play group gradually expanded in the previous section was due to the introduction by playgroupmembers.
1st Stage

2nd Stage

Group 1

3rd Stage

Group 1aFormsubgroup

Friends

Play
togethera,bbGroup 2

Emergednew large
group

Group 2

RepeatingFig. 6 Social interaction process model by introducing by playgroup members(2) Playing with caregivers: The second is to play with caregivers. In this area, children were
often seen playing in the river, so visitors from outside the area, tourists, often played around therivers with their family members. From a viewpoint of the tourists, during the observation survey
in the Shinbashi place, social interactions from the toursts to the children were observed seventimes per hour. In addition, the following oral data were obtained from the ten tourists:“It looks very fun that the local children play with water dynamically and actively.”“I (or We) want to play together with them.”
On the other hand, it was also observed that children actively played with adults. When thechildren played with an adult, they could play, such as riding on adults’ backs or throwing them on
the water surface, which the children could not do with children. Once the children started to playwith an adult, who is a caregiver of another child, they all played together finally. This process wasshown in Fig. 7. The adult “c” is a caregiver of the child “a”, and once the child “b” started to playwith the adult “c” (the first stage in Fig. 7), the child “a” and “b” played with the adult “c” (thesecond stage in Fig. 7). Then The adult “c” introduced the child “b” to child “a” and they played all
together finally (the third stage in Fig. 7). This process was confirmed eleven times during theobservation survey.
1st Stage

Child
“a”
Child
“b”

FamilyAdult“c”

2nd Stage

Child
“a”
Child
“b”

3rd Stage

Adult
“c”

Child
“a”
Child
“b”

Fig. 7 Social interaction process model of playing with caregiversⒸ ISERD

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Adult
“c”

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

CONCLUSION
There were several findings from this study.
Firstly, river play frequency and preference of children were positively related to thefrequency of daily use of rivers by their family members and neighbors. Secondly, the SNA
showed that the interaction density of children playing around the rivers gradually increased while
repeatedly fluctuating up and down. Thirdly, the two factors for the emergence of children’s social
interactions were identified: introducing by the playgroup members and playing with caregivers.
In addition, although the hiring survey of this study was conducted in 2010, the authors also
conducted supplementary interviews with local children playing around the river in this area in
2016, and have confirmed that the children yet played around river dynamically and their social
interaction was formed through river play by introducing by playgroup members and caregivers(Nitta et al, 2017).
These results imply that rural rivers have the function for children to expand their local
interpersonal relationships through playing, which are supported by local communities.
Furthermore, children’s play places around rivers have the potential to become the social interface
for rural and urban communities, since the tourists were attracted by the children playing aroundthe rivers dynamically and social interactions have occurred.
ACKNOWLEDGEMENTS
This study was conducted with the cooperation of the teachers, the students, and the parents of theHachiman elementary school in the Gujohachiman. We would like to thank them for collaboration.
Also, this work is supported by the Toyo University Faculty of Science and Technology Policy
Research 2020.
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and recognition of animals and plants. Journal of the Japanese Institute of Landscape Architecture, 67 (5),647-652.
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Research article
erdIncome Generation and Expenditure of Organic Rice
Farming Households: Case Study of Preah Vihear Province,
Cambodia
CHANMONY SOK*
Graduate School of Agriculture, Tokyo University of Agriculture, Japan
Email: Chanmony0223@gmail.com

TOMOHIRO UCHIYAMA
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Japan

NINA N. SHIMOGUCHI
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Japan
Received 31 January 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract In Cambodia, organic rice farmers commonly engage in integrated farming andoff-farm activities to supplement their income. To identify factors for income optimization,
this study attempted to assess the income and expenditure structure of organic rice farmhouseholds in the Preah Vihear Province, Cambodia. Guided with a structured
questionnaire, a total of 90 and 50 randomly selected farmers were interviewed in 2019 and
2021, respectively. This study utilized both descriptive and multiple regression analyses.
Overall, farmers tended to expand their cultivation area and increase income from off-farmjobs. Particularly, large-scale farmers (5ha<) significantly expanded their farmland area andincreased their livestock and off-farm activities, while small-scale farmers (5ha>) reduced
their farmland area and increased their off-farm activities. Moreover, the multiple
regression analysis revealed that secured spare time from combine-harvester usage opened
opportunities for farmers to engage in off-farm jobs. These off-farm jobs, particularly by
male farmers, boosted their respective annual income. On the other hand, existing loans
gave several farmer respondents negative profit in 2020. Thus financial management
seemed to be a factor affecting farmers’ incomes in rural areas. For further study, farmhousehold employment choice behavior, particularly on labor mobility and off-farmactivities, is recommended.
Keywords expenditure, income, off-farm activities, organic rice, rural area

INTRODUCTION
Agricultural development is the most effective way to reduce poverty (World Bank, 2008). Twoeffective agricultural development strategies are commonly practiced: engaging in organic
agriculture and growing energy crops (Markandya and Setboonsarng, 2015). In Cambodia,
agriculture contributed to poverty reduction from 50% in 2007 to 9.4% in 2017. Moreover, rice isthe predominant crop, occupying 80% of the total crop area, and about 90% of the poor live in rural
areas and rely on rice farming for their primary income sources (NIS, 2013). The agriculture sector
still shared around 20% of GDP in 2019 (MAFF Cambodia, 2020). However, evidence suggeststhat rural households' livelihoods draw on various activities in developing countries. From ruraldevelopment and food security viewpoints, it is critical to understand the structure of farmhouseholds' earnings and income levels (Helmers et al., 2004; Tong and Phay, 2013). Located in
the Northern part of the country, Preah Vihear province is one of the main producing area oforganic rice in Cambodia. This rural province produces organic rice once a year. Thus, all farmers
have off-farm activities and produce other crop to support their daily lives. Commonly, farmers
produce rice, other crops, and livestock (e.g. cattle, poultry), and do other off-farm activities asⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

wage-earners and migrants to the city or neighboring country to do other jobs to maximize theirincomes (Preah Vihear Provincial Department of Agriculture, 2019). Little research has been
performed on organic farm households' expenditure and income generation, especially in rural
areas (Uddin and Takeya, 2006). However, no researcher has measured the expenditure and income
generation of organic rice farm households in integrated farming based on-farm size and family
structures (e.g. gender, age, family member, and off-farm activities) in Cambodia.
OBJECTIVE
This study aims to assess the income and expenditure structure of organic rice farm households in
the Preah Vihear province, Cambodia, to determine the most suitable choice for organic rice farmhouseholds to maximizing income. Specifically, this study aims to identify the characteristic oforganic rice farm households in the study area; clarify the structure of income sources of farmhouseholds; and assess their expenditures.
METHODOLOGY
Study area: Data collection was conducted in Preah Vihear province, the largest organic riceproducing area and largest contract farming area in Cambodia. This region was characterized as arural area, with 85% of the population (approximately 60,605 households in 2019) relying on
agriculture. Hence, farmers were the main actors in this rural area.
Sample selection: Questionnaire survey and in-depth interviews were conducted randomly of 50
organic rice farmers in contract farming during the fields survey 2021. Collected data were
processed and compared with the previous field survey of 90 respondents in 2019 in the same study
area. Qualitative data were also collected regarding constraints, opportunities, and other impact
factors, including environmental and social factors.
Data analysis: Descriptive and multi-regression analyses were utilized. The multiple-regression
model below was adopted from Uddin and Takeya (2006) study.
Ln AI = ln a + b1 ln X1+ b2ln X2 + b3ln X3 + b4ln X4+ b5ln X5+ b6ln X6 + b7ln X7 + b8ln X8 +Ui
Ln = Natural logarithm
Y = Annual income of farm householda = Constant or intercept of function
X1 = Total owned land
X2 = Working days per year on farm activities by male
X3 = Working days per year on farm activities by female
X4 = Working days per year off-farm activities by male
X5 = Working days per year off-farm activities by female

X6 = Family member
X7 = Family member engage in Agri.
X8 = Age of head household
b1…b8 = Coefficients of respective
variables;Ui= Error terms.

RESULTS AND DISCUSSION
Farmer respondents were divided into three groups according to their owned land size, as shown in
Table1. Family members and members engaged in agriculture decreased yearly, for overall farmers
and or group categories. From 2018 to 2020, farmers seemed to increase their cultivation areas.
However, only farmers who own land more than 5 ha increased their cultivation areas, and farmers
who own land larger than 10 ha expanded all their cultivation areas in a fast pace. In contrast,
farmers who own land less than 5 ha seemed to decrease their rice cultivation. From fieldobservation, farmers tend to operate inherited land and sell some of their land. They were more
involved in off-farm activities than on-farm activities.
Table 2 shows income sources and expenditure of farmer respondents in the study area. The
main job of farmer respondents are organic rice farming. However, since organic rice could only be
produced once a year, farmers need to do other jobs to increase their annual incomes as shown inⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Table 2, such as other crops farming (cassava, cashew nut), vegetable farming, livestock, and offfarm jobs (e.g. wage earner from other farm, construction workers, small grocery owner,
government officer). From Table 2, income from rice farming remained high, but income from offfarm jobs farmers are increasing annually. In general, farmers had lower incomes in 2020 except
for those who owned less than 5 ha. Farmers who owned land more than 5 ha relied more onorganic rice farming compared to other farmers, thus the impact of natural disasters was also high.
At the same time, farmers are also increasing income from livestock, and other crop farming,
Farmers who own larger than 10 ha increased their livestock farming income in a fast pace. Fromthe interview, farmers said that even though the use of agricultural machinery is still limited, either
owned or rented, and it has secured them more time to do off-farm jobs or expand their cultivatedland.
Table 1 General characteristic of farmers respondents from 2018 to 2020

Table 2 Income sources and expenditure of farmers by year and groups
unit: thousand riels/household

All the essential daily or monthly expenditures of farm households are included in Table 2
except the production cost of farming. More than 50% of total expenses accounted for foodconsumption. Farmers are also willing to invest more in their children's education, about 15% of
total expenses, and more than 15% for farmers with land larger than 10 ha in 2020. Moreover, theannual loan tends to increases because farmers are more engaged with loans to increase cultivatedland or other purposes, and farmers who own larger than 5ha are more involved with the loan.
Farmers mainly borrowed from banks, micro-finance, and a small amount of money fromagricultural cooperatives, with the monthly interest rates ranging from 1.75% to 2.5%. In addition,phone payment is increasing because recently, farmers have recently started to use smartphones toreceive more information. Lastly, other expenses in Table 2 included health care, social/religious
ceremonies, and house repair. As shown in Table 2, farmers could not sufficiently save in 2020,and from observation, several farmers lost their profit in 2020, which will be further discussed inTable 3.
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Fig. 1 Percentage of income sources by farmer groups
Source: Field survey in 2019 and 2021

Table 3 Income sources and expenditure of farm households who lost profit in 2020
unit: thousand riels/household

Although most farmers reported that the main job is rice farming, Figure 1 clearly shows anatural shift of farmer income sources to off-farm activities. Moreover, only farmers who own landless than 5 ha rapidly increase off-farm jobs and decrease share income and cultivated rice farming
land from 2018 to 2020. This can be attributed to farmers selling of inherited rice cultivated land.
In addition, farmers who own land 5 to 10 ha are increasing off-farm, and other crops farming andfarmers who own land larger than 10 ha are more increasing in livestock because they have larger
land and capital.
During the field survey in 2021, some farmers had no profit due to high expenses, as shown intable 3. All those farmers spent more on paying loan interests, while the income in 2020 decreased.
From field observation, farmers who owned land between 5 to 10 ha engaged more in loans to
expand their land cultivation and other activities. Unfortunately, the rice yield was low, which
decreased income, and farmers could not afford the repayment. In addition, some farmers who
owned less than 5 ha needed to sell their lands to afford the repayment to the bank, which madefarmers decrease their owned land, while those who owned land of more than 5ha sold theirlivestock and other machinery to repay the loan. Those problems made these farmers further
smaller in scale. Therefore, farmers seemed to need to understand more about financial
management to lower risk in the future.
Table 4 shows the result of multiple-regression on total annual income with working labors,family members, and age of farm households in 2020 by dividing into two groups: farmers who
owned less than 5ha and a combination of all farmers who owned land larger than 5ha. It should be
noted that the farmers who owned more than 10 ha were not grouped separately due to smallⒸ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

sample size of nine respondents. As a result, besides the land size, off-farm activities significant
increased the total annual income. Working off-farm jobs for male has boosted their annual income,
especially farmers who owned less than 5 ha. On the other hand, working on the farm for females
resulted to negative impact because female farmers are only good at transplanting and harvesting.
During land preparation, most female families go together to cook for their husbands or family
members at the fields and do side-works nearby, such as picking some dead trees. On-farm work ofmales is much better during land preparation and other works. Besides that, family members,
members engage in agriculture, and the age of the head of households are not significant toincrease the income.
Table 4 Multiple-regression of model of farm households’ incomes based on groups< 5 ha (2020) (20 respondents)(Intercept)
Land size
Working on-farm male
Working on-farm female
Working off-farm male
Working off-farm female
Family members
Family members engage in farming
Age

Estimate
11.2140.612
0.139-0.073
0.330
0.292
0.227
0.190
0.145

Std. error
1.483
0.345
0.094
0.137
0.136
0.236
0.238
0.272
0.350

t-value
7.558
3.724
1.462
-1.534
2.422
2.082
0.942
1.991
0.416

Pr (>|t|)
0.000
0.011
0.171
0.303
0.032
0.064
0.360
0.116
0.580

Std. error
3.191
0.253
0.270
0.281
0.073
0.060
0.230
0.130
0.132

t-value
4.627
5.221
2.051
-1.954
2.815
1.739
0.396
1.080
0.603

Pr (>|t|)
0.000
0.000
0.053
0.064
0.010
0.097
0.696
0.292
0.553

***
*

*
*

Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1Multiple R-squared: 0.6657, Adjusted R-squared: 0.5247> 5ha (2020) (30 respondents)(Intercept)
Land size
Working on-farm male
Working on-farm female
Working off-farm male
Working off-farm female
Family member
Family member engage in farming
Age

Estimate
14.7661.324
0.554-0.550
0.208
0.105
0.091
0.140
0.079

***
***
.
.
*
.

Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1Multiple R-squared: 0.742, Adjusted R-squared: 0.640
Source: Field survey in 2021

Table 5 Total annual income and labors input by group in 2020

Income sources(Thousand riels/HH)

Labors input(People/HH)

Items
Number of households
Rice
Other crops
Off-farm
Vegetable
LivestockTotal income
Total labors
Rice (male)
Rice (female)
Other crops (male)
Other crops (female)Off-farm (male)Off-farm (female)
Source: Field surveys in 2021

Overall
50
%
4,300
35
1,739
14
6,389
51
637
5
2,884
23
12,429
100
436
100
47
11
49
11
21
5
19
4
201
46
101
23

Less than 5 ha
20
%
2,312
17
869
6
7,977
58
517
4
2,165
16
13,840
100
462
100
33
7
34
7
10
2
10
2
231
50
143
31

Ⓒ ISERD60

5 to 10 ha
21
%
4,316
31
1,906
14
4,705
34
772
6
2,316
17
14,015
100
366
100
51
14
52
14
21
6
21
6
159
44
61
17

More than 10 ha
5
%
9,477
33
3,585
12
6,645
23
600
2
8,489
29
28,796
100
550
100
74
13
79
14
44
8
36
7
227
41
91
16
1 USD = 4,050 riels

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Even the regression analysis showed that farmers could boost their annual incomes byengaging in off-farm activities in the current situation, farmers who used about 22% of total labor
inputs on rice farming only received about 35% of total income (Table 5). On the other hand,
farmers who used about 70% of total labor on off-farm activities received about 51% of total
income. This conveys that farmer may achieve more labor and income efficiencies by organic rice
farming. However, seasonality of organic rice farming and difficulty in expanding land for organic
rice cultivation (mainly small-scale farmers) are the core reasons on further shifting to off-farmactivities.
CONCLUSION
In general, the cultivation area has been increasing from 2018 to 2020. Farmers who own land
more than 5 to 10 ha increased all the cultivated lands, especially on other crops. However, farmers
who own less than 5 ha seemed to rapidly increase their off-farm jobs and decrease their rice land.
Regarding expenditure, farmers spent more than 50% of total expenses on their foodconsumption, followed by 15% spendings on their children’s education. This trend is prevalent tofarmers are currently more engaged in loans. Unfortunately, several farmers (especially farmers
who owned land less than 5ha) could not repay the loan in 2020, forcing them to sell their lands orother properties to repay the loan and making small-scale farmers further smaller in scale.
However, rice farming still seemed to offer opportunities for farmers to boost their annual
incomes in terms of labor inputs and incomes if farmers could expand their rice land and do proper
financial management.
Nevertheless, instead of expanding rice cultivation, farmers (especially farmers who owned
less than 5ha) tend to increase their annual income by engaging in off-farm jobs in the current
situation. On the other hand, farmers who owned less than 5 ha are better off in securing morespare time to do off-farm jobs, especially males, have more potential to boost the farm households'
annual incomes.
Therefore, farm households' employment choice behavior, particularly labor mobility, offfarm activities, and loans, is recommended for further study to find more solutions for maximizing
the farm households’ income.
ACKNOWLEDGEMENT
The authors wish to extend sincere appreciation to Research Institute for Agricultural and Life
Sciences (RIALS) for partially supporting this research.
REFERENCES
Helmers, K., John, G. and Pia, W. 2004. Final report of the rural sources of income and livelihood strategies
study. Memo, World Bank.
Markandya, A. and Setboonsarng, S. 2015. Organic crops or energy crops? Option for rural development in
Cambodia and the rao people's democratic republic. ADB Institute Discussion Paper, 101.
Ministry of Agriculture, Forestry and Fisheries (MAFF). 2020. Annual report of agriculture, forestry, andfisheries 2019-2020. Ministry of Agriculture, Forestry and Fisheries, Phnom Penh, Cambodia.
National Institute of Statistic (NIS). 2013. Cambodia socioeconomic survey 2013. National Institute of
Statistic, Cambodia, 23-28.
Preah Vihear Provincial Department of Agriculture. 2019. Annual report for agriculture, forestry, andfisheries 2018-2019. Provincial Department of Agriculture, Preah Vihear Province.
Tong, K. and Phay, S. 2013. The role of income diversification during the global financial Crisis: Evidence
from nine villages in Cambodia. Working Paper Series, 78.
Uddin, T.M. and Takeya, H. 2006. Employment patterns and income generation of farm households in
integrated farming of Bangladesh. International Journal of Agricultural Research, 1 (1), 32-40.
World Bank. 2008. World development report 2008: Agriculture for development. World Bank, 28-29.
Retrived from https://openknowledge.worldbank.org/handle/10986/5990Ⓒ ISERD

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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

Research article
erd

Economic Assessment of Tea Smallholder Farmers underContract Farming in Rungwe District, Tanzania
ISSA ABRAHAMAN KACHENJE*
Graduate School of Agriculture, Tokyo University of Agriculture, Japan*
Email: 13822001@nodai.ac.jp

NINA N. SHIMOGUCHI
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, JapanKATSUMORI HATANAKA
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Japan

RAMADHONA SAVILLE
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Japan
Received 31 January 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract In Tanzania, tea is considered as one of the most exported crops. The mainstakeholders of the tea industry are smallholder farmers and estates. Smallholder tea
farmers are required to engage in contract farming, as stipulated in the Tea Regulation of
2010. This study attempted to assess contract farming and its impact to production andincome of tea smallholder farmers in Rungwe District, Tanzania. A total of 48 randomly
selected smallholder farmers were interviewed using a semi-structured questionnaire in
September 2020 and October 2021. Agribusiness company officials, government officials
and extension officers were also interviewed to clarify the condition and issues of thecontract farming scheme. Descriptive analysis and cost and return analysis were utilized.
Results show that yield, income, and profitability increased from 2016-2019. These can be
attributed to steady supply of inputs, easy access to technical assistance, and early adoptionof new technology under contract farming scheme. Moreover, the price of smallholder
green leaf has improved, with farmers receiving a second payment hence improve theiroverall revenue returns.
Keywords: contract farming, smallholder farmers, tea, profitability, Tanzania

INTRODUCTION
Tea is a globally manufactured and widely consumed beverage (Hicks, 2009; Onduru et al., 2012).
Kenya, Malawi, Uganda, Tanzania, Zimbabwe, South Africa, and Rwanda are the principal teaproducing countries in Africa, with tea contributing considerably to their economy (FAO, 2014).
By the year 2023, the continent's export volume is expected to reach 743,384 metric tons
(FAOSTAT, 2015).
Tea is the fifth most exported crop in Tanzania, the tea sector accounts for an average ofapproximately USD 50 million every year, when it comes to foreign exchange earnings. Tea
industry also contribute to the huge amount of employment opportunities as it employs more than
50,000 families and indirectly it affects to as many as 2 million Tanzanian citizens (Baffes, 2004).
Moreover, the nature of tea production necessitates a significant amount of labor, implying that thesector can employ a large number of people. Tea can be harvested all year round, making it one of
the few crops that can generate a relatively consistent income when compared to seasonal crops
like maize.
Tea cultivation was only done on a large scale under the supervision of several tea estates
during colonial and early post-colonial times, which meant that smallholder farmers were nonⒸ ISERD62

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

existent. Smallholder tea production legally began only after the independence in 1960s. At thattime the government had actively pushed smallholders’ involvement in the tea sector (Maghimbi etal., 2011; Gibbon, 2011). This marked the starting point for the co-existence and relationshipbetween the smallholders and estates in the tea sector. The relationship was later on cemented with
the introduction of programs such as contract farming and sales agreements. Further, smallholders
are required by law to have at least a one-year sales agreement in place. This is due to a number offactors: Firstly, the tea leaves' perishable nature; green leaves can only be stored for around six
hours before they must be processed. Secondly, tea processing also demands complex and costly
machinery, which is why the majority of tea processing firms are owned by large corporations. As
a result, smallholders are reliant on tea processing plants owned by large tea companies. This
mandates close collaboration between smallholder farmers and estates that possess processing
plants, hence makes sales agreements and contract farming necessary in Tanzania tea sector.
OBJECTIVE
The main goal of the study was to assess contract farming and its impact to production, income,and profitability of tea smallholder farmers in Rungwe District, Tanzania.
METHODOLOGY
Study Area
This study was conducted in Rungwe district (see Fig. 1) located in the Southern tea growing zone.
Two villages from the Rungwe district namely Katumba and Lugombo village were purposively
selected because these villages large concentration of smallholder farmers operating under acontract system. A total of 48 randomly selected smallholder farmers were interviewed using asemi-structured questionnaire in September 2020 and October 2021. Agribusiness company
officials, government officials and extension officers were also interviewed to clarify the condition
and issues of the contract farming scheme.

Fig. 1 Map of the study area
Source: Google map

Methods of Study
For evaluating the impact of these Contract Farming schemes on yield, income, and profitability oftea per unit area, cost and return analysis was utilized. Furthermore, the study compared the yield,
income, and profitability of smallholder tea farmers from the year 2016 to 2019.
Fixed costs, such as family labor and land charges, were separated from variable costs, such as
herbicides, chemical fertilizers, pesticides, and hired labor. The gross return was then obtained bymultiplying the marketable produce by the year's average price per kilogram. The profit was thencalculated by subtracting the total cost from the gross return.
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RESULTS AND DISCUSSION
This study estimated the cost of producing green tea leaves for smallholder tea producers in the
Rungwe district of Mbeya, Tanzania, as well as the revenue generated. In the study area, Pesticides,
herbicides, and farm labor both family and hired labor are among the inputs used by smallholder
tea farmers. On the other hand, Chemical fertilizers, such as NPK fertilizers, Glyphosate, Urea, andSA fertilizer, are also used. Additionally, other farm inputs include safety Goggles, Gloves, Gum
Boots, Raincoat, Mouth Mask, Shears, and Spray Pump are often used by smallholders in the study
area. This section analyzed the production costs and profitability of smallholder farmers
participating in Contract Farming in greater detail. Most of these inputs are provided on credit tosmallholder tea farmers in the study area by their contracting estates. The inputs are distributed
according to a well-established process that is overseen by smallholder association leaders andextension officers. The loaned inputs are paid for by deducting from the overall earnings that
smallholder farmers are expected to gain without any interest.
Yield of Green Tea Leaves Produced by Smallholder Tea Farmers
The yield of a crop is calculated by dividing the amount of crop harvested by the harvested area ofthat crop. Mathematically, the yield can be calculated by dividing production data by harvested
area data.
According to the findings, the marketable yield for smallholder tea leaves in 2016, 2017, 2018,and 2019 was 1,093 kg/ha, 1,175 kg/ha, 1,247 kg/ha, and 1,347 kg/ha, respectively. This is
attributable to a steady supply of inputs, easy access to technical assistance, and the adoption of
new technologies in the study area's contract farming scheme. Similarly, the contracting company
has stepped up its efforts to provide smallholder farmers with inputs such as fertilizers andherbicides at significantly lower prices than market prices, allowing them to have easy access to
supplies at a reasonable price.
Table 1 Comparison of the average yield for smallholder tea farmers
2016

2017

2018

n=(kg/ha)2019

National

814

1,082

1,203

1,035

Study area

1,093

1,175

1,247

1,347

Items

Source: Field survey in 2020

The Costs of the Inputs for Green Leaf Tea Production
The overall production cost was estimated, which included not only the cash payment but also theestimation of the opportunity cost for smallholder farmers. There are two types of costs inagriculture: variable and fixed. In general, variable costs fluctuate according to the degree of
production. Fixed costs, on the other hand, are expenses that do not change regardless of
production level. According to Mamun et al. (2018), the total cost (TC) can be obtained by adding
the total variable cost (TVC) to the total fixed cost (TFC), as illustrated in the equation below.
TC = TVC +TFC

(1)

Where TC is total costs, TVC is total variable cost and TFC is total fixed cost.
In this study, the total cost was calculated by adding the costs of chemical fertilizers,
herbicides, farm equipment, and labor used by smallholder farmers for producing green tea leaves
in the study area.
Moreover, in an effort to improve green tea leaves production volume and quality in the study
area, the amount and frequency of provision of various farm inputs such as herbicides, chemicalⒸ ISERD

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fertilizers and other equipment were increased which resulted into the increased cost of production
as shown in the table 6.1. According to the findings, the total production cost of green tea leaves
per hectare was 65.65 TZS/ha, 73.32 TZS/ha, 102.13 TZS/ha, and 112.07 TZS/ha in 2016, 2017,2018, and 2019 respectively.
Green Tea Leaves Price in the Study Area
In the study area, for the years 2016, 2017, 2018, and 2019, the contracting company's green tea
leaves price per Kg in the research region was 231 TZS/Kg, 240 TZS/Kg, 315 TZS/Kg, and 320
TZS/Kg, respectively. These prices offered to smallholders in the study area are higher than thegovernment's recommended price (basal price), implying that farmers in the study area benefit
more than green tea leaf growers in other tea producing areas, such as the Korogwe district in thenortheast zone, where smallholder tea producers receive no more than the government's
recommended price.
Table 2 Total production cost and profitability of smallholder tea production(Unit: 000’ TZS/ha)
Items
Observed smallholders

2016

2017

2018

2019

(n=48)(n=48)(n=48)(n=48)

0.3

0.3

0.3

0.3

Average cultivated area (ha)Yield (Kg/ha) (AA)

1,093

1,175

1,247

1,347

Chemical fertilizer costs (C1)

8.14

9.09

12.66

13.90

Herbicide’s cost (C2)

10.80

12.34

18.10

20.09

Farm Instruments (C3)

2.04

2.28

3.18

3.49

Hired labor cost (C4)

15.62

17.45

24.31

26.67

Total variable cost (TVC)=(C1+C2+C3+C4)

36.61

40.89

56.96

62.50

Family labor cost (C5)

27.77

31.02

43.21

47.42

Total labor cost (C6) = C4+C5

43.39

48.46

67.51

74.08

Total production cost (C7)=TVC+C5

65.65

73.32

102.13112.07Gross revenue (GR) = (AA*Farm gate price)

252.48282.00392.81431.04Gross income (GI) = (GR-TVC)

215.87241.11335.85368.54Gross profit (GP) = (GI-C5)

188.10210.09292.64321.12

Smallholder Tea Farmers’ Revenue, Income and Profitability in the Study Area
The gross income (GI), gross revenue (GR) and Gross profit (GP) were estimated using data fromthe field survey 2020 and 2021 to better understand the impact of tea leaves production on thesmallholders’ livelihood. The study then simulated the comparative profitability of growing green
tea leaves in various years from 2016 to 2019. This will help to determine the trend of grossincome, gross revenue, and profitability received by smallholder tea farmers each year, as well as
ranking the profitability received over this period of time.
Gross revenue (GR) means the amount received by farmers presumably that their entire
volume of marketable yield is sold at the farm gate price. Dammert and Mohan (2015) support thatthe concept of Gross Revenue is calculated as yield multiplied by farm gate price. Further, Gross
income (GI) is computed by subtracting total production costs from Gross Revenue, excluding
family labor costs. Finally, gross profit is derived by subtracting family labor costs from grossincome.
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IJERD – International Journal of Environmental and Rural Development (2022) 13-1

The results showed that in 2016, 2017, 2018, and 2019, the gross revenue for smallholder tea
leaves production was 252.48 TZS/ha, 282 TZS/ha, 392 TZS/ha, and 431.04 TZS/ha, respectively.
Likewise, the results showed that in 2016, 2017, 2018, and 2019, the gross Income for smallholder
tea leaves production was 215.87 TZS/ha, 241.11 TZS/ha, 335.85 TZS/ha, and 368.54 TZS/ha,
respectively.
Table 3 Price of green tea leaves in TZS
Items
Tea leaves price/kg

2016

2017

2018

2019

231

240

315

320

Source: Field survey in 2020.

CONCLUSIONFirstly, land ownership of smallholder tea farmers was overwhelmingly male dominated,suggesting that land ownership for women is a major issue in African traditions and culture as aresult of gender biased traditions. As a result, women's ability to participate in Contract Farming(CF) in Africa is compromised. Also, low level of education among the smallholder tea farmers
was also observed. in terms of farm size, smallholder tea farms were relatively small (averaging
0.30 hectares). Inadequate farm size, on the other hand, may limit households' ability to expand
their cultivation and fully exploit the benefits provided by Contract Farming programs in order tomaximize productivity while utilizing the far more advanced technologies. Finally, the findings
revealed that farming is the principal economic activity of the entire sample of respondents in the
study area.
In the study area, smallholder tea farmers received prices higher than the government's
recommended price, implying that farmers in the study area benefit more than green tea leaf
growers in other tea-producing areas, such as the northeast zone's Korogwe district, where
smallholder tea producers receive no more than the government's recommended price. Furthermore,
smallholder farmers in the study area benefited not only from the higher price than the government
recommended, but also from the introduction of a first and second payment system after thecompany's sales of the made tea, based on cost sharing and final market price, which improved
their overall revenue returns.
Over the four years for which data were gathered, the trend of Marketable Yield has risen. As
a result, in 2019 the highest marketable yield was obtained, whereas in 2016 the lowest yield was
obtained. Furthermore, data obtained shows that smallholder farmers in the study area produced
higher yields than the country's average yield for each of the four years examined. This is owing toa steady supply of inputs, easy access to technical assistance, and the adoption of innovativetechnology in the study area's contract farming scheme. Similarly, the contracting company has
stepped up its efforts to provide smallholder farmers with inputs such as fertilizers and herbicides
at much cheaper prices than market prices, allowing them to have easy access to supplies at anaffordable price. And because of the higher price and yield, smallholders in the Contract scheme
were able to generate more gross revenue, gross income, and profit compared to national averagefor smallholder tea farmers. In general, contract farming in the tea sector appears to be profitable
for respondent smallholder tea farmers in the study area.
However, the need for a higher price for their tea leaves, difficulty adapting to newtechnologies, insufficient input supplies, insufficient funds to hire extra farm labor, and insufficient
farm equipment were shown to be the challenges that smallholders experience.
Generally, the contract farming system in the study area has a positive impact on production,
income, and profitability of tea smallholder farmers, despite the existence of some constraints. In
light of the findings and conclusions, the study recommends that the government, agribusinesscompanies, smallholder famers association and other stakeholders develop a common strategy andways for smallholder tea farmers to have better access to capital in order to boost their adaptabilityⒸ ISERD

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to new technologies, buy sufficient farm input and farm equipment, and have sufficient funds tohire extra farm labor to further improve their profitability.
ACKNOWLEDGEMENTS
We are grateful to the Tokyo Nodai Foundation and the More Job Better Life [MJBL] Foundation
for funding this study.
REFERENCES
Baffes, J. 2004. Tanzania’s tea sector: Constraints and challenges. Africa Region Working Paper Series 69.
Dammert, C.A. and Mohan, S. 2015. A survey of the economics of fair trade. Journal of Economic Surveys,
29 (5), 855-868.
Food and Agriculture Organization (FAO). 2015. Supporting sustainable agriculture development for ahunger free Africa in the next 10 years.
Food and Agriculture Organization Corporate Statistical Database (FAOSTAT). 2015. Production quantities
by country. Retrieved from https://www.fao.org/faostat/en/#home
Gibbon, P. 2011. Experiences of plantation and large-scale farming in 20th century Africa. DIIS Working
Paper 2011, 20.
Hicks, A. 2009. Current status and future development of global tea production and tea products. AU Journalof Technology.
Maghimbi, S., Lokina, B.R. and Senga, A.M. 2011. The agrarian question in Tanzania? A state of the art
paper. Current African Issues, 45.
Mamun, A., Rahman, A. and Afrooz, N. 2018. A socio-economic analysis of private plant nursery businessin Bangladesh. The Agriculturists, 16 (2), 102-114.
Onduru, D.D., De Jager, A., Hiller, S. and Van den Bosch, R. 2012. Sustainability of smallholder tea
production in developing countries, Learning experiences from farmer field schools in Kenya.
International Journal of Development and Sustainability, 1 (3), 714-742.

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Research article
erd

Performance Assessment of Simple Covered Lagoon
I
Digester in Large-scale Pig
Farm in Cambodia
7de
CHAN MAKARA MEANn
Biogas Technology and Information Center,
Royal University of Agriculture, Phnom Penh,t

Cambodia
Email: meanmakara321@gmail.com 4.
7
Biogas Technology and Information Center / Faculty of Agricultural Engineering,
2

LYHOUR HIN*Royal University of Agriculture, Phnom Penh, CambodiawoBiogas Technology and Information Center/ Faculty of Agricultural Engineering,
Royal University of Agriculture, Phnomr Penh, Cambodiads
DYNA THENG

LYTOUR LOR

Biogas Technology and Information Center / Faculty of Agricultural Engineering,
Royal University of Agriculture, Phnom Penh, Cambodia

MAKARA LAY
Biogas Technology and Information Center, Royal University of Agriculture, Phnom Penh,
Cambodia / Department of Science and Technology, Linköping University, Norrköping, Sweden

BART FREDERIKS
Biogas Technology and Information Center, Royal University of Agriculture, Phnom Penh,
Cambodia
Received 31 December 2021

Accepted 22 April 2022(*Corresponding Author)

Abstract Simple covered lagoons are used to treat wastewater from commercial pig farms
in Cambodia into biogas. The electricity is generated from biogas using a generator.
However, high level of H2S corrodes or breaks down the generator. This study aims todesulfurize biogas with commercial ferrous oxide pellets (Fe2O3). The effects ofdesulfurization system on biogas production, electricity generation, and CO2 reduction are
discussed. The results show that H2S was reduced from 2,000 ppm before treatment toaround 50 ppm after treatment. CH4 (57.7 ± 8.76%) and CO2 (24.7 ± 2.67%) contents were
not affected by desulfurization. O2 content was changed from 0.3 to 4.8%. High O2 level
was a sign of pipe leakage, lowering CH4 and eventually electricity production. The
increase of O2 level decreased CH4, thus lowering generator performance. Actual electrical
output power produced from biogas was 368.5 ± 29.3 kW, with loading rates of 57.6 ±
4.6% and generator efficiency of 26.8 ± 1.7%. Estimated amounts of 22,818 tCO2equ werereduced by the biogas system. The desulfurization system was highly effective in H2S
removal without affecting biogas quality. For the long-term biogas systems in Cambodia,
local-made desulfurization systems should be tested and compared with imported products.
Keywords biogas, CO2 reduction, simple covered lagoon, CH4, desulfurization,
electricity generation

INTRODUCTION
Globally, the energy sector that covers electricity, heat, and transport contributes to 73.2% of GHG
emissions, whereas livestock accounts for 14.5% (Quinton, 2019). To produce one kWh ofⒸ ISERD

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electricity, 0.657 kg CO2 is produced. Meanwhile, a fattening pig ready for slaughter produces
448.3 kg CO2 (Philippe and Nicks, 2015).
To tackle these issues, zero-emissions in all sectors are discussed in the 26th United Nations
Climate Change Conference of the Parties (COP26) held in Glasgow, Scotland, with its intended
achievements to keep global warming below 1.5oC this century, specifically targeting CH4
reduction (UNEP, 2021). According to IPCC (2014), CH4 is 28 more potent than CO2 regarding the
100-year global warming potential, so letting it into the atmosphere is much more harmful to theenvironment. Climate change mitigation in livestock production can be done by anaerobic
digestion (AD) technology (Achinas et al., 2017).
In Cambodia, commercial pig farms have increased due to their ability to control theenvironment necessary for fast pig growth and effective disease prevention (MAFF, 2019). In those
farms, evaporative cooling systems are used to maintain temperatures of 25 to 27oC inside thebarns (Thanapongtharm et al., 2018). In consequence, electricity consumption is an average of 30
kWh per head (Putmai et al., 2020). Daily wastewater generated from sows, fatteners, and piglets is
64, 24, and 20 m3 head-1, respectively (Kulpredarat, 2016). It has been reported that the pig farmwith fattening pigs above 3000 heads have a potential to produce biogas through AD technology.
A common AD type used to treat wastewater from commercial pig farms in Cambodia is a
simple covered lagoon digester, with 44 units reported in 2019 (NBP, 2019). They are preferred
due to its low-cost construction, easy operation (Rahman and Borhan, 2012) and its suitability for
wastewater that contains 0.5 - 2% of dry matter (DM). Hin et al. (2021) found that wastewaterfrom pig farms in Cambodia contains 0.9% DM.
Biogas is a gas mixture that contains CH4 (60 - 70%), CO2 (30 - 40%), and other traceelements (Okoro and Sun, 2019; Safferman et al., 2007). CH4 is the only source of energy to
produce heat and electricity for farm use. Nevertheless, biogas contains high hydrogen sulfide(H2S) concentration up to 3,500 ppm (Hin et al., 2021; Dumont, 2015). H2S is corrosive to theengine and toxic to humans. H2S level must be limited to 200-500 ppm for generator operation(Rodrighez et al., 2014). Generally, H2S removal can be done physically by regulated air injection(Hines et al., 2019), chemically by application of sodium hydroxide (NaOH), potassium hydroxide(KOH), or Ferrous oxide (Fe2O3) (Zulkeflia et al., 2016), or biologically by the use of biofilters(Barbusiński and Kalemba, 2016). However, proper desulfurization techniques are little known in
Cambodia, especially for large-scale biogas systems. The study aims (1) to compare biogas quality
before and after being treated with ferrous oxide (Fe2O3) fed in a Chinese commercial
desulfurization system, (2) to determine the working capacity of the biogas generator, and (3) toevaluate biogas production, electricity production, the generator efficiency, and CO2 reduction
equivalence.
MATERIALS AND METHOD
Materials
The tools used in this study included A biogas 5000 analyser, supplied by Geotech, UK and Hioki
PW3365-20-01/5000 power logger (Hin et al., 2021).

Fig. 1 Geotech biogas 5000 (left) and Hioki PW3365-20-01/5000 power logger (right)Ⓒ ISERD

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Methods
The research was conducted from January to August 2021 in a large-scale pig farm that raised
38,000 fattening pigs and 3,100 sows under cooling evaporative systems in Sihanoukville Province,
Cambodia. The farm used a full biogas system: a simple covered lagoon digester (76,000 m3
volume), a biogas desulfurization system fed with 2,400 kg of Fe2O3, a flow meter with maximum
flow rate of 500 Nm3 biogas, two 640-kW second-hand biogas generators, and a flare used to burnexcess biogas. The desulfurization rate was 0.5 kg Fe2O3 per 1 Nm3 biogas.
The biogas 5000 analyser was used to measure biogas quality before and after being treatedthrough the desulfurization system filled with Fe2O3 at blowing pressure of 5.6 kPa. Due to travel
restriction inside the farm, the data were recorded once a month for 7 consecutive months. Eachtime, measurements were made three times to obtain average values. The power logger was
attached to the generator wiring for 3 hours at a time of data collection to measure actual output
power produced from biogas. However, actual output power could be measured only with the posttreated biogas because there was only one outlet pipe connecting the biogas desulfurization system
to the generator.
Data Sampling
The collected data were CH4 (%), CO2 (%), H2S (ppm), and O2 (%). Hourly biogas flow (Nm3 h-1)
and biogas temperature (oC) were also recorded by using the flow meter that exists in the system.
Additionally, four formulas were used in this study as follows. In formula one, CO2 reduction
equivalent (tCO2 equ.) by avoidance of CH4 emission equals CH4-to-CO2 equivalent x CH4 density
x Annual CH4 production, while CO2 reduction by avoidance of grid electricity equals electricityto-CO2 equivalent x annual electricity demand met by methane production. CH4-to-CO2 equivalentis 28, and electricity-to-CO2 equivalent is 0.657 kg CO2 per kWh (Hin et al., 2021). In formula
three, Electrical loading rate (%) equals output power divided by the rated power. Formula four isthe generator efficiency (%) which was calculated by dividing the output power by the powerchemically produced through the internal combustion of biogas. Net caloric value (NCV) of biogas
with 60% CH4 is equal to 20 MJ Nm-3. Thus, the chemical power (kW) produced by biogas
combustion is equal to hourly biogas consumption by the generator multiplied by NCV and divided
by 360.
Data Analysis and Interpretation
Data were analyzed using the R studio version 4.1.1. Paired sample t-test was employed to compare
the biogas quality before and after desulfurization. A simple linear regression was used to identify
relationship between CH4 and O2. A contour plot was used to determine the effects of biogas flow
and CH4 concentration on active output power produced from the generator. Descriptive statistics
were utilized to depict generator performance, biogas generation, and CO2 reduction.
RESULTS AND DISCUSSION
Biogas Quality
Biogas quality before and after desulfurization system was compared (Fig. 2). Differences in H2S
were detected (P < 0.001; Fig. 2a) and it was reduced from 2,061 ± 138.9 ppm before treatment to50.1 ± 10.2 ppm after treatment. However, one month after the utilization of Fe2O3, H2S rose to
more than 200 ppm. The pre-treated H2S level is similar from previous studies (Dumont, 2015) and(Hin et al., 2021). On the other hands, CH4 and CO2 was 57.7 ± 8.76% and 24.7 ± 2.67%,
respectively and was not affected by desulfurization (Fig. 2b). These values were lower, whencompared to the literature by Safferman et al. (2007) for pig manure in Europe and by Hin et al.
(2021) for pig manure in Cambodia and by Wongsapai et al. (2008) in Thailand. Low CH4 and CO2Ⓒ ISERD

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values tends to be affected by the atmospheric air that penetrated into the system through pipelines
or the edges of the lagoon plastic cover sheet.
Relationship of CH4 with O2 and Average Load with Biogas Flow and CH4
We studied the relationship between CH4 and O2 to determine why CH4 content was relatively low,
as seen in Fig. 2b. Fig. 3a shows that CH4 decreased with the increase of O2 (P < 0.001; R2 = 0.92).
When O2 increases by 1%, CH4 decreases by 4.64%. Normally, O2 level in raw biogas is low. A
recommended level of O2 entering the lagoon should be in the range of 0.3-3% (Hines et al., 2015).
So, its high content in this study may signify air penetration into the system, which can be throughthe pipelines, water traps, or the edges of the lagoon plastic cover sheet. In case leakage is found at
the lagoon, high O2 inhibits methanogenic activities because CH4 is strictly produced underanaerobic conditions (Botheju and Bakke, 2011). The result of this study is similar to that
conducted by Hin et al. (2021). Thus, proper detection is required to inspect pipelines, water traps,
and the covered lagoon.

Fig. 2 Comparison of H2S (a) and CH4 and CO2 (b) before and after desulfurization(Mean ± SD; N = 21)
Paired sample t-test was used for the analysis. Different alphabetic letters denote significant differences atthe error level of 0.05, and NS means non-significance.

Fig. 3 Relationship between CH4 and O2 (a), and determination of average load
as a function of biogas flow and CH4 (b)The low CH4 reduces the biogas generator performance. Figure 3b indicates an average load
as a function of hourly biogas consumption and CH4 content. With the same biogas flow rate, low
CH4 content reduces the amounts of electrical power produced. To maintain the same electrical
power produced with low CH4, unusual high biogas flow rates were recorded, which leads to theⒸ ISERD

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overuse of daily produced biogas. In contrast, CH4 content of 60 - 65% gives better generator
performance and reduce the hourly biogas consumption at the same output power.
Specific Biogas Characteristics for Generator Operation
Fed into the generator, the biogas was pushed by an electrical blower at 5.6 ± 0.5 kPa. Its
temperature averaged 37.0 ± 5.1oC, rated best for biogas production (Babaei and Shayegan, 2020).
Biogas system produced 4,478 Nm3 day-1, but the actual daily biogas consumption was 4,862 ±
64.6 Nm3 day-1 (Table 2). Therefore, the amount of biogas consumption was 8.6% greater than the
biogas production.
Table 1 Biogas production, electricity consumption, and CO2 reduction equivalent
Description
Biogas temperature
Estimated daily biogas production
Recorded daily biogas consumption
Biogas flow rate
Actual generator power
Specific biogas consumption
Actual output power
Chemical power produced by biogas
combustion
Loading rate
Genset efficiency
CO2 reduction equivalent
CO2 reduction equivalent per head

Unit
o
C
Nm3 day-1
Nm3 day-1
Nm3 h-1kW
Nm3 kWh-1
kW

Mean ± SD
37.0 ± 5.1
4,478
4,862 ± 64.6
237.6 ± 29.6
640
0.64 ± 0.08
368.5 ± 29.3

kW

1365.9 ± 174.9%%
tCO2equ yr-1
tCO2equ yr-1 head-1

57.6 ± 4.6
26.8 ± 1.7
22,8180.56

In Table 1, the generator was a 640-kW biogas generator, and actual electrical output power
produced from biogas was 368.5 ± 29.3 kW, so the loading rate of the generator was estimated at
57.6 ± 4.6% of its full capacity. With the hourly biogas flow rate of 237.6 ± 29.6 Nm3 h-1, thetheoretical electrical power generated from biogas was estimated at 1365.9 ± 174.9 kW. Therefore,
the generator efficiency was 26.8 ± 1.7%, and it was higher than the study by De Souza et al.
(2016) and Jeong et al. (2009). The specific biogas consumption in this study was 0.64 ± 0.08 Nm3
kWh-1, which was lower than that studied by De Souza et al. (2016), whose finding was 0.76 m3
kWh-1.
CO2 Reduction Equivalent
Using the biogas system reduces the enormous amounts of CO2 and CH4 emissions. In this study,
the CO2 reduction equivalent was estimated at 22,818 tCO2equ yr-1, or 0.56 tCO2equ yr-1 head-1.
CO2 reduction was lower than that studied by Hin et al. (2021). However, it was higher than
Peerapong and Limmeechokchai (2017), whose founding was 0.47 tCO2eq yr-1 head-1 and for Thai
pig farms. The difference in CO2 emission reduction tends to link with estimated daily manure
production.
CONCLUSION
The use of desulfurization system greatly reduced H2S, but did not affect CH4 and CO2 contents.
Biogas quality was undermined by higher O2 levels in it. With low biogas quality, actual electrical
power produced from biogas was also low. However, considerable amounts of CO2 can be cut withthis biogas system. The limitations of this study are that the biogas generator performance could be
evaluated only with already treated biogas because it is the actual farm operation and altering thesystem or reconnecting raw biogas pipes to the generator are very costly. Further research will

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improve biogas quality with locally made desulfurization systems and prolong the age of iron oxidepellet use to reduce labor and increase system operation efficiency.
ACKNOWLEDGEMENTS
The study was made possible thanks to the project “Reduction of Greenhouse Gas Emission
through Promotion of Commercial Biogas Plant in Cambodia” implemented by United Nations
Industrial Development Organization (UNIDO) that not only provided funding, but also
continuously assisted in strengthening the research team. Many thanks may also go to the farmowner that allowed for a long-term experiment.
REFERENCES
Achinas, S., Achinas, V. and Euverink, W.J.G. 2017. A technological overview of biogas production frombiowaste. Engineering, 3 (3), 299-307, Retrieved from http://dx.doi.org/10.1016/J.ENG.2017.03.002
Babaei, A. and Shayegan, J. 2020. Effects of temperature and mixing modes on the performance of municipal
solid waste anaerobic slurry digester. Journal of Environmental Health Science and Engineering, 17,1077-1084, Retrieved from DOI https://doi.org/10.1007/s40201-019-00422-6
Barbusiński, K. and Kalemba, K. 2018. Use of biological methods for removal of H2S from biogas inwastewater treatment plants, A review. Architecture Civil Engineering Environment, 9 (1), 103-112.
Botheju, D. and Bakke, R. 2011. Oxygen effects in anaerobic digestion, A review. The Open Waste
Management Journal, 4, 1-19.
De Souza, S.N.M, Lenz, A.M., Werncke, I., Nogueira, C.E.C., Antonelli, J. and De Souza, J. 2016. Gas
emission and efficiency of an engine-generator set running on biogas. Journal of the Brazilian
Association of Agricultural Engineering, 1809-4430, Retrieved from DOI https://doi.org/10.1590/18094430-Eng.Agric.v36n4p613-621/2016
Dumont, E. 2015. H2S removal from biogas using bioreactors: A review. International Journal of Energy andEnvironnement, International Energy and Environment Fondation, 6 (5), 479-498.
François-Xavier, P. and Baudouin, N. 2015. Review on greenhouse gas emissions from pig houses:
Production of carbon dioxide, methane and nitrous oxide by animals and manure. Agriculture,
Ecosystems and Environment, 199, 10-25, Retrieved from DOI https://doi.org/10.1016/j.agee.
2014.08.015
Hin, L., Ngo, B., Lor, L., Sorn, S., Theng, D., Dok, C., Mech, S., Mean, M.C., Yut, S., Lay, M. and Frederiks,
B. 2021. Assessment of biogas production potential from commerical pig farms in Cambodia.
International Journal of Environmental and Rural Development, 12 (1), 172-180.
Hines, A.M., Choudhury, A., Felton, G. and Lansing, A.S. 2019. Microaeration for hydrogen sulfide removal
in biogas. University of Maryland Extension, Retrieved from https://enst.umd.edu/sites/enst.umd.edu/
files/files/documents/Extension/H2S-Microaeration.pdf
Intergovernmental Panel on Climate Change (IPCC). 2014. Anthropogenic and natural radiative forcing.
Retrieved from https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf
Jeong, C., Kim, T., Lee, K., Song, S. and Chun, M.K. 2009. Generating efficiency and emissions of a sparkignition gas engine generator fuelled with biogas-hydrogen blends. International Journal of Hydrogen
Energy, 34 (23), 9620-9627.
Kulpredarat, N. 2016. The impact of pig wastewater to water environment in Thailand. Department ofLivestock Development, Thailand.
Ministry of Agriculture, Forestry, and Fisheries (MAFF). 2019. MAFF annual report 2018-2019. Ministry ofAgriculture Forestry and Fisheries, Phnom Penh, Cambodia.
National Biodiester Programme (NBP). 2019. Market study on medium-scale and large-scale biodigesters.
National Biodiester Programme, General Department of Animal Production and Health.
Okoro, V.O. and Sun, F.Z. 2019. Desulphurisation of biogas: A systematic qualitative and economic-based
quantitative review of alternative strategies. Chem. Engineering, 3, 76.
Peerapong, P. and Limmeechokchai, B. 2017. Biogas-based electricity generation in swine farm in Thailand:
Economic and CO2 reduction aspects. Energy Procedia, 138, 657-661.
Quinton, A. 2019. Cows and climate change: Making cattle more sustainable. Retrieved from https://www.
ucdavis.edu/food/news/making-cattle-more-sustainable
Rahman, S. and Borhan, S.M. 2012. Typical odor mitigation technologies for swine production facilities, A
review. Civil and Environmental Engineering, 2 (4), 1-11.
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Rodriguez, G., Dorado, D.A., Fortuny, M., Gabriel, D. and Gamisansa, X. 2014. Biotrickling filters forbiogas sweetening: Oxygen transfer improvement for a reliable operation. Process Safety andEnvironmental Protection, 92 (3), 261-268.
Safferman, S., Safferman, A., Croskey, H. and Wandersee, W. 2007. Emerging issues in animal agriculture:
Swine manure storage covers and economic tools to determine the payback period. Michigan State
University Extension, USA.
Thanapongtharm, W., Linard, C., Chinson, P., Kasemsuwan, S., Visser, M., Gaughan, E.A., Epprech, M.,
Robinson, P.T. and Gilbert, M. 2016. Spatial analysis and characteristics of pig farming in Thailand.
BMC Veterinary Research, 218.
United Nations Environment Programme (UNEP). 2021. Emissions gap report 2021: The heat is on, A worldof climate promises not yet delivered. United Nations Environment Program.
Wongsapai, W., Thienburanathum, P. and Rerkkriengkrai, P. 2008. Biogas situation and development in Thaiswine farm. Retrieved from DOI https://doi.org/10.24084/repqj06.269
Zulkefli, N.N., Masdar, S.M., Jahim, J. and Majlan, H.E. 2016. Overview of H2S removal technologies frombiogas production. International Journal of Applied Engineering Research, 11 (20), 10060-10066.

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Research article
erd

Migration Characteristics of Communities in theForestlands in Ifugao, Philippines
CARMELITO C. VALDEZ*
College of Agriculture and Forestry, Ifugao State University, Potia Campus, Philippines
Email: valdezcarmelito@gmail.com

GEMMA B. DUMANSI
Ifugao State University, Potia Campus, Philippines
Received 28 January 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract The Ifugao province as a mountainous land of indigenous people, described as awatershed framework that provides domestic and agricultural services. Greater portion of
the province was declared as Forestland. Due to increase in population, communities tend tooccupy and possess certain part of the forest to provide their basic needs. Understanding the
migration characteristics on the Forestlands in the province of Ifugao may lead to a solution
harmonizing the role of different stakeholders in maintaining the biological, physical andsocial aspect of the upland for a sustainable development. The study employed qualitative
method of research and adopted the purposive sampling technique, in data gathering
wherein, respondents are certified migrant in the forestlands of Ifugao province. It revealed
that migration in the Forestlands in Ifugao province is being influenced by many combined
factors and being prompted by poverty and aggravated by climate change. Socio-economic
aspect is the primary reason why people tend occupy portion of the Forestland. Theyacquire portions of the Forestland as a source of living as they are engaged in farming as
their main source of livelihood.
Keywords indigenous people, resource management, land use system

INTRODUCTION
Philippines is about 30 million hectares, half of which is classified as forestland, 47 percent isclassified as alienable and disposable land and the remaining three (3) percent is unclassified
forestlands. Alienable and disposable (A&D) lands refer to those areas which may be issued withpermanent title and/or used for varying purposes such as for residential, agricultural, commercial
and other uses. Of the country’s 14.19 million hectares of A&D lands, 9.63 million hectares are
already titled (DENR, 2017). On the other hand, Forestlands are lands belonging to the state andcannot be alienated unless provided by law. Much of the Forestland are hilly and mountainous withslope of ≥ 18% hence are deemed not suitable for agricultural purposes as legally defined by the
Revised Forestry Code of 1975 (Esplana and Quizon, 2017).
Most of the Forestlands of the country are occupied by indigenous communities. The
Philippines is a culturally diverse country with an estimated 14-17 million indigenous people (IP’s)
belonging to 110 ethno-linguistic groups, they are concentrated in Northern Luzon and Mindanao
and some in Visayas (De Vera, 2007; UNDP, 2010). Indigenous Peoples/Indigenous Cultural
Communities (IP/ICC) refer to a group of people sharing common bonds of language, customs,
traditions and other distinctive cultural traits, and who have, under claims of ownership since time
immemorial, occupied, possessed and utilized a territory (IPRA Law). Thirty three percent (33%)
of the IP population is located in the Cordillera Administrative region and sixty one percent (61%)
are living in the mountain ranges of Mindanao (UNDP, 2010). As the population in the uplands
continuously increasing, the demand for a land to cultivate and for housing is becoming more
important thus, the widespread opening of forest for livelihood in the Philippines is pragmatic andnatural resources become degraded.
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The Cordillera Administrative Region (CAR) is composed of six provinces Abra, Apayao,
Benguet, Ifugao, Kalinga and Mountain Province. It is considered as the watershed cradle of thenorth (UNDP, undated) and characterized as rugged, hilly and mountainous in topography. The
region has a total land area of approximately 1.8 million hectares. Almost 1.5 million hectares areclassified as forestlands and 0.3 million hectares is alienable and disposable lands (FMB-DENR,
2013). Cordillera culture is characterized by its diversity. The major indigenous culturalcommunities who occupy the Cordillera are the Ibaloy and southern Kankana-ey in Benguet
Province, the Ifugaos of Ifugao Province, the Bontok and northern Kankana-ey of Mountain
Province, the Kalingas of Kalinga, the Isnag of Apayao, and the Tingguian of Abra. There are
numerous smaller distinct ethnic groups and subgroups within these provinces, such as the
Balangao, Kalanguya, and Karao. The groups vary in their political, kinship, economic, andreligious organizations (Mendoza and Brett, 2004).
The Ifugao province in particular is a landlocked watershed province bounded by a mountain
range to the north and west that tempers into undulating hills towards the south and the east. The
highest elevation is 2,523 meters above sea level (masl) with the rice terraces lying above 500 masl.
Ifugao province is located at the southern portion of the Cordillera Administrative Region (CAR)
found at the heart of Luzon Island of the Philippines. It is home to the indigenous peoples who callthemselves “Ifugaos” and is host to one of the world-renowned rice terraces clusters that the
UNESCO World Heritage List of cultural and natural properties considered to be of “outstanding
universal value. In the land Classification of The Philippines 2013 as published by the Forest
Management Bureau of the Department of Environment and Natural Resources (FMB-DENR,
2013) Ifugao province has approximately 251,778 hectares and 90 % (226,369 has.) of which isdeclared as forestland only 10% (25,409 has.) is considered as Alienable and disposable lands(A&D). The province has growing population and communities in the forestlands are tremendously
increasing.
This study aimed to examine the migration characteristics and identify major drivers offorestland occupation in the province of Ifugao, Philippines.
METHODOLOGY
Research Design
This study utilized qualitative research. Data were gathered through Focus Group Discussion(FGD) to the Forestland migrants in Ifugao, Philippines. Moreover, the data were validated througha key informant interview (KII). Likewise, actual field visit was conducted to document current
scenarios of upland faming, resource management and practices in the area.
Sampling and Respondents
Purposive sampling technique was employed in this study. Identified Forestland migrants that
represents different sectors of the upland community were interviewed for this purpose, particularly
sectors coming from youth, Barangay officials, elders, upland famers, women’s group and technicalpersonnel from the Department of Environment and Natural Resources (DENR), and Departmentof Agriculture (DA).
Use of Vignette in the Study
The focus group discussion (FGD) in each of the study sites were conducted in a panel andconsolidated in a common understanding of the respondents in a scheduled interview session withthe researchers per group or representation in the area. There are seven (7) interview sessions withthe different respondents to represent the Forestland migrants (n = 5), Barangay officials (n = 5),
elders (n = 3), upland farmers (n = 5), representative from women’s group (n = 5), and technicalpersonnel from the Department of Agriculture (n = 5), and Department of Environment and NaturalⒸ ISERD

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Resources (n = 5). On the completion of the data gathering through the focus group discussion(FGD), each group were asked on their understanding on the migration and migration
characteristics in the province of Ifugao in the Philippines. particularly on the pattern of migration
related to their age, educational attainment, ethnicity, gender, marital status, religion, culture,income, source of income, farming practices, crops being planted and natural resourcesmanagement since they are living in a vulnerable forest landscape in the province. This vignette
pattern was applied in the three selected study sites in the province of Ifugao in the Philippines.
The consolidated result of the study was presented to the different respondent representatives
through key informant interview (KII) to confirm the veracity and reliability of the data gathered
during the focus group discussion.
Study Sites
The municipalities of province were stratified into three categories according to elevation: The low
elevation (192 - 500 meters above sea level); the Mid-elevation (501 - 1000 meters above sea level)
and; High Elevation (Above 1000 meters above sea level). To represent the mentioned categoriesof the different municipalities of the province, convenient method was considered in the selectionof the study sites. Accordingly, Barangay Little Tadian in the municipality of Alfonso Lista,
Barangay Itab in the Municipality of Aguinaldo and Barangay Nattum in Mayoyao were selected torepresent the Low elevation, Mid-elevation and High elevation, respectively.

Study sites

Fig. 1 Map of Ifugao, Philippines
RESULTS AND DISCUSSION
Migration can be a temporary outlet for population pressure but often it only creates a new
population pressure and new environmental scenario in the area of in-migration. The typicalmigration pattern worldwide has been from rural to urban areas (Amacher et al., 1998) however,this pattern has reversed in the 1980’s particularly in the South East Asia and the Amazon as
migrants leaving impoverished cities to settle in sparsely inhabited upland and forest frontiers andPhilippines is an example of this situation (Amacher and Hyde, 1996).
Summary of the Vignette
The study focused on the migration characteristics of communities in the Forestlands in theprovince of Ifugao in the Philippines. This study was participated by the different stakeholders of
the forestland of Ifugao in Philippines such as migrants, women’s group, elders, Barangay officials,
technical personnel from the DA and DENR respectively. As a result of the study, migration to theforestland in the province of Ifugao in the Philippines confirmed three (3) major causes to includeⒸ ISERD

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cultural, demographic and socio-economic factors that is consistent with the findings of Li et.al(2014) consequently, there are factors affecting migration intensions in an ecological area such as
demographic factors, socio-economic factors and other factors (political-economic factors and ecoenvironmental factors).
Three (3) Major Causes of Migration in the Forestlands in Ifugao, Philippines
A. Cultural factor: Majority of the Forestland settlers in Ifugao in the Philippines belongs to theIndigenous People (IP) of the province, some are coming from the neighboring provinces of Nueva
Vizcaya, Isabela, and Mountain Province. Indigenous people in Ifugao have a natural connection toforest resources because it is their nature to engage in hunting wild animals for food, andsustainable forestry as they acquire lumber for domestic purposes in their woodlots (Muyong).
They also extract wild honey for their personal consumption and some are for sale as they augment
their income. More importantly, it is their culture to seek for a fertile land for agriculture
production or technically known as kaingin.
B. Demographic factors: Demographic factors are the general indication of a group in the general
population in the forestland in the province of Ifugao such as age, gender, marital status andreligion.
Accordingly, migration to the forestlands in the province by the community happens usuallyduring the young to middle adult ages from 18-38 years old because during this stage individuals
are active explorer, traveler and adventurous as they seek job, belongingness, enjoy the value ofnature, and in the search of partner in life. In addition, people would like to settle in a place
wherein they are going to construct their own houses, established sustainable source of living,
invest time and properties in an area, and this is usually happening in the young adult stage.
Consistent with the argument of Abu et al. (2014) that during older age, people may not migrate
because their attachment to their community tends to be stronger than that of younger age. On theother hand, male have higher incidence of migration in the Forestlands in Ifugao, Philippines
because they are usually the once engaged in the search of livelihood for the family including
acquisition of land to be tilled, hunt for wild animals, harvest wild plants and fruits. Moreover,establishment and settlement in an area is a role of males in the upland particularly in the provinceof Ifugao in the Philippines.
Majority of the respondent in the different locations in accordance to the criteria set in thisstudy pointed that families occupy portion of the forestland in the province of Ifugao with theirrelatives and establish a community in the area. Communities in the Forestlands of Ifugao is
composed of different spiritual sectorial belief such as Pentecostal, Roman Catholic, Evangelical,
and Baptist Ministry. Accordingly, their religious belief binds them together and guide them for apeaceful and happy well-being. The significance of Religion to the migration characteristics ofcommunities is relevant to the interpretation of Hirschman (2004) that relatives and distantindividuals move towards an area of worship and religious networks of similar belief, supported by
the idea of Portes and Rumbaut (2006) that religious practices is a source of social capital and an
important variable in determining the path of assimilation within the segment of social structure.
However, religion do not figure predominantly in migration (Cadge and Ecklund, 2007).
C. Socio-economic factors: Socio-economic condition is an important factor in shaping
development goals of a community. In general, it analyses how economic activity affects and isshaped by social processes. It is one of the major bases in the determination of inequalities andimportance in development. In this particular study, educational attainment, household size,
occupation and land holdings were considered in the migration characteristics of communities in
the Forestlands in Ifugao, Philippines.
Majority of the Forestland migrants in Ifugao in the Philippines are Elementary graduate andhigh school level, some populations are high school graduate and college level, only few of the
populations are considered professional who finished their formal education in college and earned
their Baccalaureate Degrees. In terms of household size, large family can describe the compositionof Forestland migrants in the area, which is characterized by an average of eight (8) householdⒸ ISERD

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members that is composed of a father, mother and children. On the other hand, the primaryoccupation of the migrants is upland farming, some are involved in wood carving, and carpentry.

Kaingin in Mayoyao, Ifugao, Philippines(Planted with upland Rice)

Kaingin in Aguinaldo, Ifugao, Philippines(Planted with Corn)

Fig. 2 Kaingin within the forestlands in Ifugao, Philippines
Generally, families are moving towards the Forestlands in Ifugao in the Philippines because ofsocio-economic pressure brought about by poverty and aggravated by climate change. People tend
to occupy certain portion of the Forestland to acquire land holdings for them to establish theirhouses and more importantly to have lands to till and generate income for subsistence. They open
portions of the Forestlands by slash and burn through cutting and clearing the original vegetation
and are planted with agricultural crops such as upland rice, corn, vegetables and some potion areconverted into grazing land. Accordingly, planting of agricultural crops in the Forestland can be
harvested in 3-4 months and generate income in a shorter period of time compared to engagementof tree farms or tree plantation that will take 10-15 years before the fast-growing tree species canbe harvested and atleast 30 years for an indigenous or native species. Moreover, their engagementin agricultural production can provide basic needs for their family such as food, clothing andmedicine, and send their children to school. Upland farmers generally cultivate potions of theForestland on the basis of occupancy, residency and agricultural engagement in the area. In theabsence of any tenure instrument, their cultural rights as the original tenant over the land is being
respected by the community.
The trend of migration to the Forestland in the Ifugao in the Philippines is increasing,communities are already in place and agricultural production areas are becoming dominant in thearea. The increasing number of populations in the Forestland were observed to have negative
impact on the natural agro-ecological system in the area. As a result of agricultural production in
the moderate to steep slopes areas in the Forestland, there is a significant increase in soil erosion,and siltation in the water ways. Biodiversity of flora and fauna also are affected since the crops
being grown by the communities are not indigenous particularly the vegetables, and corn that arecultured for a medium to large scale production. Moreover, the introduction of chemicals in themaintenance of their farms particularly herbicides, and insecticides brought damages to both micro
and macrobiotic diversity of the area.
CONCLUSION
The migration characteristics of communities in the Forestlands in Ifugao in the Philippines ischaracterized by a dynamic and complex cultural, demographic, and socio-economic factor.
Nowadays, the continuous increase in the population in the Forestland is brought about by poverty
that cause families to occupy, posses, and utilize portion of the Forestland for agricultural
production for subsistence and provision of basic needs by the people.

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ACKNOWLEDGEMENTS
The authors extend grateful thanks to the Ifugao State University-Research, Development,
Extension and Training (RDET) Department for the funding and continuous support to researchendeavors of faculty members of the institution.
REFERENCES
Abu, M.S., Codjoe, S. and Sward, J. 2014. Climate change and internal migration intentions in the forestsavannah transition zone of Ghana. Population and Environment, 35 (4), 341-364, Retrieved from DOI
https://dx.doi.org/10.1007/s11111-013-0191-y
Amacher, S.G., Cruz, W., Grebner, D. and Hyde, F.W. 1998. Environmental motivations for migration:
Population pressure, poverty, and deforestation in the Philippines. Land Economics, 74 (1), 92-101.
Cadge, W. and Ecklund, H.E. 2007. Immigration and religion. Annual Review of Sociology, 33, 359-379,
Retrieved from https://www.annualreviews.org/doi/pdf/10.1146/annurev.soc.33.040406.131707
Department of Environment and Natural Resources (DENR). 2017. Land resources. Department ofEnvironment and Natural Resources website, Retrieved from https://www.denr.gov.ph/news-andfeatures/latest-news/55-land-resources.html
Esplana, M.R. and Quizon, A. 2017. Status of reform tenure in the public lands under the comprehensive
agrarianreform program. Asian NGO Coalition for Agrarian Reform and Rural Development, Retrieved
from https://ilc-nes.ph/wp-content/uploads/2017/07/Tenure-Reform-in-Public-Lands-under-CARP_Final_24-March-2017.pdf
FMB-DENR. 2013. The Philippine forest facts and figures. Department of Environment and Natural
Resources, Quezon City, Philippines, Retrieved from http://forestry.denr.gov.ph/pdf/ref/PF3_2013.pdf
https://aboutphilippines.ph/files/Communal-Land-Management-in-the-Cordillera-Region-chap02.pdf
Hirschman, C. 2004. The role of religion in the origins and adaptation of immigrant groups in the UnitedStates. International Migration Review, 38, 1206-34, Retrieved from DOI https://journals.sagepub.
com/doi/10.1111/j.1747-7379.2004.tb00233.x
Li, Y., Lopez-Carr, D. and Chen, W. 2014. Factors affecting migration intentions in ecological restoration
areas and their implications for the sustainability of ecological migration policy in arid Northwest China.
Sustainability, 6, 8639-8660, Retrieved from DOI https://doi.org/10.3390/su6128639
Official Gazette of the Republic of the Philippines (GOVPH). 1997. Indigenous peoples rights act 1997.
Republic Act 8371, Retrieved from http://extwprlegs1.fao.org/docs/pdf/phi13930.pdf
Perera, J. 2009. Land and cultural survival: The communal land rights of indigenous peoples in Asia.
Retrieved from https://www.adb.org/sites/default/files/publication/27980/land-cultural-survival.pdf
Portes, A. and Rumbaut, G.R. 2006. Immigrant America: A portrait (2nd ed.). Berkeley University California
Press, USA.
United Nations Development Program. 2013. Indigenous peoples in the Philippines. Retrieved from https://www.undp.org/philippines/publications/fast-facts-indigenous-peoples-philippines
De Vera, D.E. 2007. Indigenous people s in the Philippines: A case study. Retrieved from http://www.
iapad.org/wp-content/uploads/2015/07/devera_ip_phl.pdfⒸ ISERD

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Research article
erdDiscussion about A Model in Operation and Accumulation of
Joint-Use Fund Management by Rice Farmer-groups
YUKI TOYAMA*
United Graduate School of Agricultural Sciences, Tottori University, Tottori City, Japan
Email: yukiuki1019@gmail.com

ASRES ELIAS
Faculty of Agriculture, Tottori University, Tottori City, JapanKUMI YASUNOBUFaculty of Agriculture, Tottori University, Tottori City, Japan

PANATDA UTARANAKORN
Faculty of Agriculture, Khon Kaen University, Khon Kaen District, Thailand
Received 30 January 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract Substantial number of rice farmer-groups are established under the promotion ofgroup farming policies in Thailand. The groups voluntarily form joint-use funds and operate
their business with them. The objective of this study is to make the model of joint-use fundmanagement by rice farmer-groups with two approaches: 1) observing the characteristics of
successful cases in the rice farmer-groups established by two policies in Northeastern
Thailand; and 2) simulating a fund management on the groups based on one case group in
Khon Kaen province. The case groups established funds using the resources provided by
the government. Through operating the group’s business, members invest in-cash or in-kind
input and pay the service charges into the fund. Then the accumulated capital was used forproviding returns to members’ investments and scaling-up the groups’ business. Based on
actual accounting data of one case group, we simulated revolving joint-use fund by rice
farmer-group. The result showed that the group assumed to accumulate enough amount ofassets to provide sufficient service for all members using the initial fund derived fromgovernment support. A conceptual model of joint-use fund management for the rice farmers
group was described. The model will be utilized to guide rice farmer-groups in developing
their business and becoming independent from government support.
Keywords group farming, community, government support, northeastern Thailand

INTRODUCTION
Small and family-run farms are evaluated as important agents to achieve a stable and sustainable
food supply (FAO and IFAD, 2019; FAO, 2014). Generally, in the area where small family farms
are dominant, most farmers face challenges to scale-up their business because of land
fragmentation and lack of production resources (HLPE, 2013). On the other hand, group farming is
one of the major means to improve the productivity of small family farms facing resource
constraints. It helps to achieve economies of scale and respond to the external environment. For
instance, East Asian countries (e.g. Japan and South Korea) achieved a dramatic improvement inagricultural productivity through spreading group farming (Wong, 1977).
In Thailand, the government adopted group farming concept into agricultural development
policies and established many farmer-groups, especially related to rice production. Some studies
mentioned that the rice farmer-groups received in-cash and in-kind resource supports fromgovernment and operated their business through managing and utilizing joint-use funds (Ohara etal., 2021; Tanaka and Yasunobu, 2019). It is also indicated that a substantial number of groups
stopped their operation in the early years because of the difficulty to continue their businessⒸ ISERD

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(Uchook, 2018). At present, the joint-use funds are voluntarily operated by members of the groups.
However, to the best of our knowledge, there is no manual and/or guideline regarding how suchkind of activities have been implemented. Therefore, to suggest a model of handling joint-use fundis supposed to be benefitable for encouraging farmer-groups to continue/expand their business.
OBJECTIVE
We consider a model of joint-use fund management by rice farmer-groups in Thailand throughachieving the following objectives: 1) To investigate the characteristics of joint-use fundmanagement among the groups which continuously accumulate the fund; 2) To simulate the cycleof accumulating joint-use fund and scaling-up the business; and 3) To conceptualize joint-use fundmanagement for depicting a model based on the above results.
METHODOLOGY
To achieve the objectives of this study, we adopted the following approaches. First, we explored
the actual situation of how rice farmer-groups manage their own business and joint-use fund, withthe cases of rice farmer-groups established by the encouragement of policies. Then, we conducted
the simulation of revolving joint-use fund based on one case which conducted the lending businessof combine harvester and kept its account record, and finally, the conceptual model was induced
from the results.
Survey Site Selection
In this study, we selected cases of rice farmer-groups located in Khon Kaen and Ubon Ratchathani
provinces in, the Northeastern region. The groups were established under the promotion of twopolitical programs: Community Rice Seed Center (CRSC) and Large Land Plot of Rice (LLPR),
proceeded by the Ministry of Agriculture and Cooperatives (MOAC), Thailand.

Fig. 1 Changes in the distribution of rice production scale among farmers in Thailand
Source: Author’s creation with the data opened at the website of Office of Agricultural Economics, Ministryof Agriculture and Cooperatives, Thailand [https://www.oae.go.th].
Remark) 1 rai = 0.16 ha.

To consider modeling of joint-use fund management, the domain (area and crop) which needs
the model is suitable for the target in this study. In Thailand, Northeastern region and Central
region are the main production areas of rice. The production scale of rice on each farm inNortheastern region is smaller than Central region and group farming policies aiming at small-scale
rice farmers are mainly extended in Northeastern region. Moreover, in Northeastern region, theratio of large-scale farmers is decreasing in total number of rice producers. Fig. 1 shows thechanges in production scale of rice among farmers from 2008 to 2018. At the national level, theratio of farms operating more than 20 rai (= 3.2 ha, 1 rai = 0.16 ha) decreased from 29.2% to 20.0%Ⓒ ISERD

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and this tendency was especially clear in Northeastern region; the decrement on the ratio of farms
operating more than 20 rai in each region is as follows: whole country, -31%; Central, -16%;
Northeast, -44%. From the above, the model proposed by this study will be mainly applied to thefield in Northeastern Thailand and it is reasonable to adopt rice farmer-group located in
Northeastern Thailand as the cases.
Sampling and Data Collection
Various policies related to group farming have been introduced in Thailand. This study aimed thegroups established under two policies targeting rice farmers: Community Rice Seed Center (CRSC)
and Large Land Plot of Rice (LLPR).
CRSCs have been established since the beginning of 2000s (1,650 CRSCs was existed in
2016/2017) as a local supplier of rice seed (Orachos, 2018). To cope with the shortage of rice seedcertified the quality, Thai government tried to realize the self-supply of rice seed in each ruralcommunities through establishing the groups of rice farmers for engaging the multiplication ofcertified rice seed provided by the government institutions (Moonfoui et al., 2007). LLPRs are also
rice farmer-group targeting to perform the economics of scale on rice production in Thailand. The
program was started from 2016 and 3,759 plots were established until March 2022, and about 60%of them were in Northeastern region (DOAE, 2022). The activities of LLPRs are jointly
procurement and use of capital, equipment, and materials (e.g., machinery, miller, storage, rice
seed, group fund), joint shipment to the contracted miller and produce GAP certified rice or riceseed. Both two policies are promoted by the Rice Department, the Ministry of Agriculture andCooperatives, and certain number of LLPRs are established based on existing CRSCs.
Surveyed groups were 34 CRSCs (Ubon Ratchathani: 21 in 90 groups, Khon Kaen: 13 in 92
groups), and 4 LLPRs in 48 groups in Khon Kaen province. All groups were sampled randomly.
Regarding the case CRSCs, the data was originally used in Tanaka and Yasunobu (2019). Face-toface interview was conducted for group leaders with structured questionnaire in August and
September 2015. The data of case LLPRs included both of which deriving from Ohara, et al.
(2021) and which was collected by authors. On our survey, group interview to a few members
including leader was conducted regarding how to manage joint-use fund in August 2018 and July
2019.
RESULTS AND DISCUSSION
Exploring Actual Situation of Joint-Use Funds Management among CRSCs and LLPRs
Table 1 shows how CRSCs accumulated their joint-use funds. All groups accumulating more than
100,000 THB (1 Thai Baht (THB) = 0.031 US$, average in 2021) managed their funds more than
10 years. The larger funds have the tendency that the average amount of fund per member is larger.
The groups which accumulate and enlarge the funds continuously supposed to succuss increasing
the amount of resource which each member can use.
Table 1 Accumulation of joint-use funds among CRSCs
Accumulation classof joint-use fundFrequency(N = 19*2)

Averagenumber ofmembers(unit: THB*1)~99,999
100,000~149,999
150,000~199,999
200,000~

5
4
6
4

31.0
35.5
41.0
42.0

Average term ofaccumulating
fund(unit: years)
05.6
14.5
13.2
13.8

Averageamount of fund

Average amount offund per member(unit: THB)
049,547
130,000
166,417
282,413(unit: THB/member)
1,411
4,040
5,170
7,859

Source: Reorganized by author with the data treated by Tanaka and Yasunobu (2019).
Remarks) *1: THB is an abbreviation of Thai Baht (1 THB = 0.031 US$, average in 2021).
*2: Excluded 8 groups which did not answered amount of fund from 34 surveyed groups.
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Table 2 Activities for input and use of joint-use funds among CRSCs (N=27)
Input to fundIn kind return of rice seed with interest
Share sales
Membership fee
Resales of provided materials
Machinery use charge

Frequency
18
8
7
4
4

Use of fundLoan service
Purchasing materials
Purchasing seeds from members
Investment for machinery and facility

Frequency
18
13
12
8

Source: Reorganized by author with the data treated by Tanaka and Yasunobu (2019).
Remarks) Using the data of 27 groups, excluding 7 groups which did not have joint-use fund from 34 surveyed groups.

The activities for accumulating and using joint-use fund among the case groups are itemized
in Table 2. All case groups received certain amount of free rice seed as government support.
Eighteen groups divided the seed to members and then members return for the dividend in kindwith interest after harvesting. Apart from that, some groups collected membership fee or soldshares to members. The groups having machinery provided lending service for members.
Regarding use of the funds, the most major use of join-use fund was loan service for supporting
members’ livelihood. Other ways of using the fund were joint procurement of materials, investment
for expanding equipment, and compensation of rice seed sales for members.
On the other hand, in the cases of LLPRs, main income sources were revenue of machinery
lending and investment from members through selling share (Table 3). In terms of the share system,
3 of 4 case groups sold group's share to members. The shareholders could get dividend dependingon the amount of group’s revenue and the number of possessed shares. All case groups provided
members with a lending service of machinery leased by the government. The price of lending
charge was lower than the charge of private contractors in the area. In case non-members rent themachinery, the charge was higher than the price for members. However, the groups rarely lendmachinery to non-members because they did not possess enough number of machines to provide
service for all members. To prepare enough amount of machinery and equipment, and provide
services without competition, groups need to revolve their initial fund deriving from government
support and to accumulate joint-use fund for capital investment. In contrast to CRSCs, no LLPRs
provided loan service to members. Since LLPRs have operated for a few years, they did not haveenough amount of fund to launch financial business.
Table 3 Accumulation and use of joint-use funds among LLPRs
Group AGroup B

Group CGroup D

200

67

204

52

Free lending 1 trailerof machinery 2 harvesters

1 tractor
1 harvester
1 trailer
1 drill seeder

1 drill seeder
1 harvester

4 drill seeders

Provision of KDML105*1: 15 t
rice seeds RD6*1: 8.6 t(2016~2019)

KDML105: 13 t
RD6: 2 t

KDML105: 2.25 t
RD6: 15 t

KDML105: 30 t
RD6: 150 t

Share sales
Rice sales
Machine use charge

Share sales
Rice sales
Machine use charge

Share sales
Rice sales
Machine use charge

Seed sales
Machine use charge

Running cost*2
Dividend of share
Reward of committee

Running cost
Dividend of share
Reward of committee

Running cost
Dividend of share
Reward of committee
Community welfare

Running cost
Reward of committee
Machinery purchase*3

Number of members

Govt.
supportInput to fundUse of fundSource: Reorganized by author with the results of Ohara et al. (2021) and the survey in 2018 and 2019.
Remarks) *1: KDML105 and RD6 are the name of rice variety. KDML105 is non-glutinous variety, and the variety islabeled “Jasmin rice” in market. RD6 is glutinous variety which is popularly eaten in Northeastern Thailand.
*2: “Running cost” include maintenance of machinery, petrol, wedge for driver and miscellaneous expenses.
*3: Group D purchased 9 drill seeders with their own fund in 2017.

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Simulation of Revolving Joint-Use Fund on Lending Combine Harvesters
We simulated revolving joint-use fund with the experience of lending combine harvester in one
LLPR case (group A) and showed the path to accumulate joint-use resource enough to provide
services for all members. The reasons why we choose LLPR as the case of this simulation include:
LLPRs focus on joint-use of production resources, but CRSCs’ main purpose is self-supply of riceseeds and LLPR program was started later than CRSC, we could collect the detailed information
about initiation of revolving joint-use fund. The information was useful for simulating from thepoint of receiving subsidies. Among four cases of LLPRs, we could get detailed account data justfrom group A; in the cases of group B, C and D, we could not collect it because of missing some
important records of bookkeeping.
Table 4 Simulation of revolving joint-use fund based on the case of group A
Items (Unit from (1) to (8): THB*1)
1st year*2 2nd year
3rd year
4th year
5th year
Number of operated combine harvesters
2
2
3
4
5
Harvested paddy area by group’s combine harvester*3
400
400
600
800
1,000
Unit: rai (% in 1,000 rai*1 = total registered area)
(40%)
(40%)
(60%)
(80%)
(100%)(1) Total income
324,550
284,550
386,825
489,100
611,375
Rice sales*4
60,00040,00020,00000Investment from member
20,0000000Revenue of lending combine harvester*5
244,550
244,550
366,825
489,100
611,375(2) Total cost
96,72896,728
133,516
170,305
207,094
Running cost for lending combine harvester*5
73,57773,577110,365
147,154
183,943
Reward for committee members
15,40015,40015,40015,40015,400Meeting
5,193
5,193
5,193
5,193
5,193
Miscellaneous expenses
2,558
2,558
2,558
2,558
2,558
(3) Dividend for shareholders*6
29,40029,40046,66263,75980,856(4) Benefit: (1) – (2) – (3)198,422
158,422
206,647
255,036
323,425(5) Amount of fund at the beginning of FY
0198,422
106,844
63,491
68,527(6) Amount of fund at the end of operation: (4) + (5)198,422356,844
313,491
318,527
391,952(7) Cost for purchasing combine harvester0
250,000
250,000
250,000
0(8) Balance of fund at the end of FY*7: (6) - (7)198,422
106,844
63,491
68,527391,952
Source: Reorganized by author with the results of the survey in 2018 and 2019.
Remarks) *1: 1 THB = 0.031 US$ (average in 2021). 1 rai = 0.16 ha.
*2: 1st year’s data is based on the actual account information of group A in 2017/18. The cost-benefit datafrom 2nd to 5th year is estimated based on the data of 1st year.
*3: On the simulation, volatility of harvested area caused by disasters or/and crop failures is not considered.
Average area of each registered plot is 5 rai and most of them are a part of each member’s operated paddy. In
case member’s total harvested area is diminished because of disasters or/and crop failures, The area rolled bygroup’s combine harvesters is supposed not to be affected since members can use the harvesters for their
paddy plots other than registered one.
*4: The government provide LLPRs rice seed for 3 years and the amount is gradually decrease. On thesimulation, it is assumed that the group gets rice for sale from members as the return for providing rice seed
provided by the government. Therefore, the amount of “Rice sales” gradually decreases from 1st to 3rd year
and does not account from 4th year.
*5: Regarding “Revenue of lending combine harvester” and “Running cost for lending combine harvester”,
the amount is assumed to change proportionately to “Harvester paddy area by group’s combine harvester”
based on the 1st year’s data. The value rates are as follows; “Revenue of lending combine harvester”: 611
THB/rai, and “Running cost for lending combine harvester”: 183 THB/rai (including petrol cost, wage for
operator, insurance, and maintenance fee). Both of values were actual data of group A in 2017/18.
*6: “Dividend for shareholders” is estimated based on the following calculation. When the group established,
all members purchased 1 share (100 THB / share) and they receive dividend form the group’s revenue equally.
The amount of dividend was 20 % of the balance between “Revenue of lending combine harvester” and “Totalcost” = (2).
*7: “Balance of fund at the end of FY” = (8) is entirely carried forward as “Amount of und at the beginning of
FY” = (5).

As shown in Table 4, group A had 200 members and 1,000 rai registered paddy field (5 rai foreach member). Each combine harvester assumed to roll 200 rai in one fiscal year and the cost ofpurchasing one combine harvester was set 250,000 THB. If the fund accumulated more than
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simulation is to prepare the number of combine harvesters which is enough to harvest on all
registered paddies. Based on the above assumptions, the group can independently continue its
function after the withdrawal of government supports. The group purchased combine harvester andexpanded its business from third fiscal year. When the number of combine harvester reach to five,the group achieved to prepare enough number of combine harvesters for providing all memberswith a lending service.
Conceptual model of Joint-Use Fund Management in Rice Farmers-group
Based on the observation of actual cases and the simulation of revolving joint-use fund, we induced
a conceptual model of joint-use fund accumulation by rice farmer-group (Fig. 2).
This model was formed on the precondition which farmer-group receive an initial provision of
goods (e.g., free lease of machinery, rice seed, fertilizer) from the government. Group members
bring in-cash and in-kind inputs as investments (share purchase or membership fee) and charge ofservices (machinery charge or in-kind return for seed provision). Accumulated capital on the fundis used for providing returns to members (lending machinery, joint procurement of rice seed,
dividend for members who hold shares).Through this input-use cycle, the group keeps enlarging
their fund even after finishing the 3 years provision of materials from the government and successto accumulate enough amount of fund (including cash and fixed assets) to provide sufficient returns
for all members.

Fig. 2 Conceptual model of revolving joint-use fund by rice farmer-group
CONCLUSION
The aim of this study is to simulate a model for the joint-use fund management using cases of rice
farmer-groups located in Northeastern Thailand.
We found both of rice farmer-group (CRSCs and LLPRs) managed joint-use fund through thecycle of input/use. The groups provided services to members with the resources provided by thegovernment and investments from members. A revenue generated by the group was accumulated asa joint-use fund and used for dividend to members, running cost, and capital investment. We
simulated this management cycle of joint-use fund with the account information of one LLPR
group in 2017. The result of the simulation showed that the group can increase the amount of jointuse fund and the scale of operation in terms of machinery rental service to members. From the thirdyear, the group became to keep running their operation without government support, and in thefifth year, the group can scale-up their operation enough to provide service for all members.

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From the simulated result, we depicted a conceptual model of joint-use fund management onrice farmer-group. The figure showed that farmer-groups form an initial fund with resources
provide by government. Through revolving the input-use cycle with the initial fund, the groups
keep enlarging the size of join-use fund even after reducing government support and achieve toaccumulate joint-use fund enough to provide sufficient service for all members. This discussion
showed the potential path in which famer-groups could become independent from government
support through voluntary joint resource management.
However, the result should be refered with a limitation in mind. In this study, the sample size
was not enough to represent the whole situation of rice farmers groups. In addition, simulating
revolving joint-use fund was just conducted with regard to lending service of combine harvester.
The simulation also had the limitation related to a reliability of result because the conditions wereassumed based on just one case of LLPRs. From the above, the conceptual model still stands on
many assumptions.Therefore, further studies are required considering more cases of rice farmergroup on top of including other activities contributing for accumulation of joint-use fund.
ACKNOWLEDGEMENT
This research was supported by the Nippon Agricultural Research Institution and JSPS KAKEN
Grant Number JP17H01490.
REFERENCES
Department of Agricultural Extension (DOAE). 2022. Large scale agricultural promotion system. Ministry ofAgriculture and Cooperatives (MOAC), Thailand, Retrieved from https://co-farm.doae.go.th/graph/
Dashboard1dsb.php
Duangbootsee, U. 2018. Thailand’s large-scale farming model: Problems and concerns. Food and Fertilizer
Technology Center for Asia and Pacific Region, Agricultural Policy Platform, Retrieved from https://
ap.fftc.org.tw/article/1347
Food and Agriculture Organization (FAO). 2014. The state of food and agriculture, Innovation in family
farming. FAO, Rome, Italy, Retrieved from https://www.fao.org/publications/sofa/2014/en/
Food and Agriculture Organization (FAO) and International Fund for Agricultural Development (IFAD).
2019. United nations decade of family farming 2019-2028. Global Action Plan, Rome, Retrieved fromhttps://www.fao.org/3/ca4672en/ca4672en.pdf
Hight Level Panel of Experts (HLPE). 2013. Investing in smallholder agriculture for food security: A reportby the high level panel of experts on food security and nutrition. World Food Security, Rome.
Lipton, M. 2005. The family farm in a globalizing world: The role of crop science in alleviating poverty.
2020
Discussion Paper 40, International Food and Policy Research Institute, Retrieved from http://cdm15738.
contentdm.oclc.org/utils/getfile/collection/p15738coll2/id/59428/filename/59429.pdf
Moonfoui, J., Radanachaless, T., Gypmantasiri, P. and Utumpan, R. 2007. Potentials of community rice seedcenters in developing towards self-reliance in seed, A case study in Phayao Province. Journal of
Agriculture, 23 (2), 155-164.
Ohara, M., Yasunobu, K., Elias, A. and Poungchompu, S. 2021. The effect of large-scale farming policy onrice farm management in Thailand: A viewpoint of production technology and agricultural gross income.
Journal of Agricultural Development Studies, 31 (3), 38-42, ISSN 0918-9432, Japan.
Orachos, N. 2018. Rice seed system in Thailand. Agricultural and Rural Economics Working Paper,
Department of Agricultural and Resource Economics, Faculty of Economics, Kasetsart University,
Thailand, Retrieved from https://ageconsearch.umn.edu/record/284028?ln=en
Tanaka, J. and Yasunobu, K. 2019. Current situation of rice seed production and community rice seed groups
in northeastern Thailand. Journal of Agricultural Development Studies, 30 (l), 33-42, ISSN 0918-9432,
Japan, Retrieved from https://agriknowledge.affrc.go.jp/RN/2010928259 (in Japanese)
Wong, J. 1977. Group farming in Asia: Experience and potentials. Singapore University Press, ISBN 0821405-21-7, Singapore.

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Research article
erd

Product and Market Diversification Trends: The Case of
Horticulture Exports in Kenya
JANE GITHIGA*
Graduate School of Sustainability Science, Tottori University, Tottori City, Japan
Email: githigajane@gmail.com

ASRES ELIAS
Faculty of Agriculture, Tottori University, Tottori City, JapanKUMI YASUNOBUFaculty of Agriculture, Tottori University, Tottori City, Japan
Received 31 January 2022

Accepted 22 April 2022(*Corresponding Author)

Abstract One of the major successes of trade liberalization in Kenya was promotion ofhorticultural exports. This was aimed at reducing export earnings instability that resulted
from declining commodity prices of tea and coffee. The export promotion programs put inplace in the 90s paid off and horticultural exports was able to record its strongest period of
growth in the 2000s. In this period the major horticulture export product was French beansin which the EU was the primarily market. However, the global markets have beenchanging posing new challenges of increased competition and regulatory standards which
could threaten the survival and sustained participation of Kenyan horticultural exports. At
the same time creating opportunities to increase export products and expand market accessthrough transfer of knowledge, skills, and technology. For many developing countries
diversification into new products and markets has been encouraged by development
platforms to deal with trade related shocks that emanates from reliance of one market and anarrow range of products. Therefore, the objective of this study was to analyze the trends ofproduct and market diversification of horticulture exports in the periods 2002 to 2019 in
Kenya using UNComtrade data. We employed the Hirschman-Herfindahl index to measureproduct and market diversification. The study finds that the horticultural products are lessdiversified while the index for the market diversification showed are more diversified
markets access. This shows that horticultural products have not increased instead
concentrated into the same products while widening market access to other regions despite
the EU markets controlling the largest share of exports. The results highlight the need toincrease the export products and take advantage of untapped potential markets.
Keywords diversification, horticulture, exports, Hirschman-Herfindahl index

INTRODUCTION
Dependence on the EU market has been a striking feature for Kenyan horticultural exports sector
since the 1990’s when it became a major supplier of French beans and other Asian vegetables(Jaffee, 2003). Despite the stiff competition, the exports have continued to grow both in volume
and value. In 2019 the sector gained over 1.07 billion USD by exporting over 328.3 thousand
metric tonnes of cut flowers, vegetables, and fruits. It is the second largest foreign exchange earner
after tea contributing 19% of total exports in 2019, and a major employer providing 350,000 jobs
directly and supporting over 6 million livelihoods (KNBS, 2020). Horticulture exports are critical
for rural development because of the commercialization of small-scale farming opportunities it
provides through contract farming. (Jaffee, 2003) found that 50% of the vegetables and 85% offruits total exports were supplied by small scale farmers while Kazimierczuk (2018) found that 5%of cut flowers were from small-scale farmers.
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From trade-led development perspective, participation in global export markets over a period
often initiate innovation and expansion in terms of market access and products exported. This canhappen in two ways; first, from market related challenges resulting from competition, changes in
consumer needs, instability in the partner markets among others. This manifested in the rapidtransformations of the EU markets in the last two decades resulting to changes in governance of the
supply chain and the way of doing business (Jaffee, 2003). It started with the evolution of Sanitaryand Phyto sanitary (SPS) standards that aimed at enhancing product safety and food quality (Jaffeeand Henson, 2004). This was extensively debated by researchers who raised concern on the market
entry barriers and threatened participation of exporters particularly from developing countries wholack infrastructure, technology and other trade related costs required to meet these standards (Jaffe
and Masakure, 2005). Consequently, in response to changing regulatory environment, the EU
market supply chain changed from previously wholesale markets to tightly integrated buyer-driven
supermarkets. (Jaffee, 2003). These supermarkets enforced their own standards too, posing further
challenges especially for small-scale farmers.
Secondly, there is opportunity by developing countries in participating in high value global
markets. Studies have found that through knowledge and skills transfer farmers develop capacity to
produce and export different varieties and use this knowledge to produce for different markets
therefore increasing market access (Jaffe and Masakure, 2005). Nevertheless, literature tend toagree that participants of horticultural exports must reorient towards meeting the changing global
markets and embracing opportunities through product and market diversification (Shepherd andWilson, 2013). Samen (2010) defines diversification as increasing the number of export products
and partner markets. Through diversifications commodity exporters can navigate through changing
market environments and market externalities resulting from dependence on a single market. The
welfare of millions the sector support depends on its ability to adapt to a highly dynamic market
and seek ways of spreading risks through diversification.
Two decades later, Kenyan horticultural exports have been increasing both in volume andvalue in a highly dynamic global market. We therefore seek to determine to what extent has the
Kenyan horticultural exports diversification trends changed over time in terms of product exported
and market access.
METHODOLOGY
The data use in the study was obtained from UNComtrade Data, aggregated in World Tradeorganisation (WTO) harmonised system (HS). The horticulture products in this study will bedefined as cut flowers, vegetables and fruits categorised by WTO HS codes. HS 06, HS 07, and HS
08 respectively. There are different methods used different studies to measure export diversification.
These methods include the Hirschman- Herfindahl index, entropy index, concentration ratio and theogive index (Samen, 2010). For our study based on available data we use the HerfindahlHirschman Index (HHI), a commonly used measure by policy makers to give summary ofdiversification. The HHI is the sum of squared export product or markets shares of country i at agiven time t. HHI index ranges from 0 to 1 and the closer the index to 0 (=diversified) while thecloser the index to 1 (= less diversified). If the HHI index is 1, it means either a country i isexporting only one product or it is the only exporter in that market.
The HHI index for product diversification was calculated by following equation.

(1)
While market diversification HHI was calculated by Eq. (2).
(2)
Where is the Si is the Share of the country i in the market, and N is the number of countries.
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(3)
RESULTS AND DISCUSSION
General Trends of Horticultural Exports Growth
Farmers are likely to venture into new products and market when there’s growth in income which isevident of increasing growth in value of horticultural exports over the period as shown in Fig. 1.

Fig. 1 Trends in value for horticulture exports
Source: Own calculations using UNComtrade

The highest growth being experienced between 2002 and 2007, a period of strong
macroeconomic stability owing to President Kibaki acceded to power in 2002. The growth howeverslows down after 2008 which can be attributed to both domestic and market factors. Domestically,
the major horticulture producing areas were affected by 2007 post-election violence followed by awidespread drought in 2009 which affected production (Tyce, 2020). As for market factors, theglobal economic crisis in 2008 affected major export markets (Heher and Steenberg, 2021). Further,delays and cancellation of flights to Europe due to Icelandic ash in April 2010 and heavy snow in
December the same year. The exchange rate volatility especially in 2016 when the Euro/USD
exchange rate dropped from 120 to 100, or delays in the signing of EPA agreement between East
African community and EU in 2015. Vegetables exports have shown more erratic in growthcompared to fruits and cut flowers. Moran (2018) found that vegetables are losing popularity due toa stringent market and some exporters are moving to cut flowers which contributes to the highest
share of horticulture exports.
Market Access General Trends
The EU market still controls the largest share of total horticulture exports although other markets
have showed potential as shown in Fig. 2. The EU controlled over 90% of total exports in 2000
which has reduced to 71% by 2019. The market with the highest potential is the Middle East which
can be attributed to the proximity it is from Nairobi as found by Irandu (2019), the closer thepartner market the higher the likelihood of trade. Although the EU controls the larger share of theexports, other markets have experienced higher average growth (Table 1).

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Fig. 2 Share of total horticulture exports according to markets
Source: Own calculations using UNComtrade data

Table 1 Average growth in % of major horticulture markets
Average growth 2001-2010

Average growth 2010-2019

EU

Market15%

3%

Middle East

29%

28%

USA

37%

4%

East Asia

21%

155%

Southeast Asia

175%

79%

Sub-Saharan Africa

61%

26%

Source: author calculation based on UNComtrade data.
Average growth was calculated using the average yearly change in percentage of total exports value. The
markets were defined used the United Nations defined regions. The United Kingdom is still included in the
EU in this analysis.

Product Diversification Trends
The objective of the study is to determine to what extent have horticultural products havediversified. This was achieved by the change in the HHI index between 2002 to 2018, if the trend
tends towards 1 (=less diversified) and if the trend tends towards 0 (= more diversified).
The study found that in all three categories of horticulture exports, the index is less than 1,
meaning that the farmers are already exporting a number of products. As shown in Fig. 3, HHI
index for combined horticulture products were 0.28 in 2002 has since rose to 0.31 meaning that thehorticultural products are less diversified and there’s no evidence of increase in additional productsin the specified period. However, if we consider the different products individually, we observed achange of pattern in vegetable category after 2012. At first the Index rises from 0.34 in 2002 to
0.38 in 2012. Then falls to 0.21 in 2018. The HHI index in the flowers category was 0.71 in 2002
and rose to 0.81 in 2018. The high index in indicates that there were only a few products exported
in this category which have continued to intensify over time while fruits HHI index rise from 0.31
in 2002 and 0.39 in 2018.
The evolution of SPS standards had a higher impact on vegetable exports compared to fruits
and flowers. This came as a challenge and opportunity, with Global GAP (formally EUREPGAP)
being rolled out in 2007, many farmers were in the process of compliance. However, there was awidespread product interception and banning of some vegetable products by the EU for failure tomeet maximum residue limits (MRL) in 2012. Farmers took this opportunity to add value to thepreviously bulk unprocessed vegetable exports and diversified into semi-processed vegetables
prepack Asian vegetables (karella, chillies, aubergines and okra) (Herher and Steenbergen, 2021).
Which could explain the HHI index for vegetable categories started falling after 2012 as anindication of additional products in the export baskets.
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Fig. 3 Product diversification trends
Source: Own calculations using UNComtrade data

The role of governance of the horticultural supply chain as a possible explanation of lessdiversified products. The “buyer -driven” supply chain where supermarkets in the EU dictate what
products to produce, the packaging characteristics and quality of products (Jaffe, 2003) is likely toaffect innovation and addition of new products. Similarly, small scale farmers on contract can only
produce what is provided the contractors. This unbalanced power dynamic observed in the export
business could hinder diversification. The same phenomenon is observed in cut flowers which has
the highest HHI index, where breeders and propagators determine what, when and how the planting
materials are distributed (Kazimierczuk et al., 2018; Tyce, 2020).
Finally, an increasing HHI index could be explained by difficulty in access to approved
planting materials especially in cut flowers exports which is associated with high cost ofinvestment that is why 95% of the farms are owned by large scale farmers and multinational
companies. High cost of royalty’s payments for the planting materials, propagating, research, anddevelopment of new varieties often locks out resource poor farmers who only produce low value
summer flowers (Kazimierczuk et al., 2018).
Market Diversification Trends
HHI index for market diversification in horticulture dropped (Fig. 4) from 0.27 in 2002 to 0.18 in2019, with vegetables showing higher market diversification where the index dropped from 0.49 in
2002 to 0.18 in 2019. Fruits HHI index dropped from 0.18 in 2002 to 0.13 in 2019 while flowers
index dropped from 0.37 in 2002 to 0.27 in 2019. The index has a slight increase between 2008 and2012, which can be explained by market factors discussed in Fig. 1 above i.e the global economiccrisis in 2008, the flight cancellations in EU markets due to weather.
The EU markets still controls the largest share of exports (Fig. 2) as discussed above which
can be explained. First, the evolution of SPS standards did not deter exporters from the EU markets,
instead most farmers embraced the compliance (Jaffee and Henson 2004). Second, the presence theforeign direct investment (FDI) coming from the EU along the supply chain such as exporters,
breeders & propagators and cool chain management and inputs (Irandu, 2019). Third, theestablished ties in the EU supermarkets could hinder further market diversification, highly
perishable products rely on trusted relationships and cost of diversion of products from one market
to another is high (Dennis and Shepherd, 2007). Fourth, availability of flights to EU that candeliver the highly perishable products in short time. Fifth, growth and advancement in Kenyan
airfreight and tourism has also aided delivery of highly perishable products in multiple destination
within a limited time. Finally Kenyan export’s ability to meet year-round demand that can
supplement their production in winter.

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Fig. 4 Market diversification trends
Source: Own calculations using UNComtrade data

There is opportunity in participation in the EU market, Kenyan horticultural exports havewidened their market access as indicated by falling HHI index both regionally and beyond (Fig. 3).
Krishna (2018) found that emergence of regional value chains has provided exporters a venue tochannel excess spillovers that don’t make it to the main markets. The experience gained from theEU markets has equipped farmers in supplying horticultural products in multiple markets governedby different regimes. However, there is still potential in untapped markets.
CONCLUSION
The aim of the study was to determine the diversification trends of Kenyan horticultural exports
this was based on the hypothesis that continued participation of farmers in a highly dynamic global
markets is likely to initiate diversification. Our results confirmed that horticultural exports are morediversified in terms of markets access as evidenced by a falling HHI index. On the other hand, we
found that the products to be less diversified meaning there is no evidence of any significant
change in number of products exported over time as evidenced by an increasing HHI index. We
further found that the EU still controls the largest share of horticulture exports. Finally, we foundthat other markets have shown great potential in terms of growth despite controlling a small shareof exports. Trade facilitation by the government could help farmers tap into those markets andincrease new products.
REFERENCES
Dennis, A. and Shepherd, B. 2007. Trade costs, barriers to entry, and export diversification in developing
Countries. Policy Research Working Paper 4368, Retrieved from https://openknowledge.worldbank.org/bitstream/handle/10986/7385/WPS4368.pdf?sequence=1&isAllowed=yHausmann, R., Hwang, J. and Rodrik, D. 2007. What you export matters. Journal of Economic Growth, 12(1), 1-25, Retrieved from DOI https://doi.org/10.1007/s10887-006-9009-4
Heher, U. and Steenbergen, V. 2021. Chapter 6, Kenya: Supplying to multinationals exposed local firms tointernational horticulture markets. An Investment Perspective on Global Value Chains World Bank,
ISBN:978-1-4648-1683-3, USA.
Henson, S. and Jaffee, S. 2004. Standards and agro-food exports from developing countries: Rebalancing thedebate. World Bank Policy Research Working Paper 3348, Retrieved from DOI https://doi.org/10.1596/1813-9450-3348
Irandu, M.E. 2019. Factors influencing growth of horticultural exports in Kenya: A gravity model analysis.
GeoJournal, 84, 877-887, Retrieved from DOI https://doi.org/10.1007/s10708-018-9888-x
Jaffee, S. 2003. From challenge to opportunity transforming Kenya’s fresh vegetable trade in the context ofemerging food safety and other standards in Europe. Agriculture and Rural Development Discussion,
Paper 2, The nternational Bank for Reconstruction and Development Agriculture and Rural Development
Department, USA.
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Jaffee, S. and Masakure, O. 2005. Strategic use of private standards to enhance international competitiveness:
Vegetableexports from Kenya and elsewhere. Food Policy, 30 (1), 316-333, Retrieved from DOI https://doi.org/10.1016/j.foodpol.2005.05.009
Kazimierczuk, A.H., Kamau, P., Kinuthia, B.K. and Mukoko, C. 2018. Never a rose without a prick:multinational companies and productive employment in the Kenyan flower sector. ASC working paper,
142 (in Dutch), Retrieved from http://hdl.handle.net/1887/64705
Kenya National Bureau of Statistics (KNBS). 2020. Economic survey 2020. Retrieved from https://www.
knbs.or.ke/economic-survey-2020/
Krishnan, A. 2018. The origin and expansion of regional value chains: The case of Kenyan horticulture.
Global Networks, 18 (2), 238-263, Retrieved from DOI https://doi.org/10.1111/glob.12162
Moran, T. 2018. FDI and supply chains in horticulture (vegetables, fruits, and flowers, raw, packaged, cut,and processed): Diversifying exports and reducing poverty in Africa, Latin America, and otherdeveloping economies. Center for Global Development, Working Paper, 475, Retrieved from DOI http://dx.doi.org 10.2139/ssrn.3125085
Samen, S. 2010. A primer on export diversification: Key concepts, theoretical underpinnings, and empiricalevidence. Growth and Crisis Unit, World Bank, USA.
Shepherd, B. and Wilson, W.L.N. 2013. Product standards and developing country agricultural exports: Thecase of the European union. Food Policy, 42, 1-10, Retrieved from DOI https://doi.org/10.1016/
j.foodpol.2013.06.003
Tyce, M. 2020. A ‘private-sector success story’? Uncovering the role of politics and the state in Kenya’s
horticultural export sector. Journal of Development Studies, 56 (10), 1877-1893, Retrieved from DOI
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Research article
erd

Impact Assessment of System of Rice Intensification
Adoption - Case from Madagascar MASATO KISHIMOTO*
Construction and Technology Institution, Tokyo, Japan
Email: seatma92@gmail.com

EIJI YAMAJI
Graduate School of Frontier Science, The University of Tokyo, Japan

TAKESHI SAKURAI
School of Agricultural and Life Sciences, The University of Tokyo , Japan
Received 31 January 2022

Accepted 23 April 2022(*Corresponding Author)

Abstract The System of Rice Intensification (SRI) is expected to improve rice yield withminimal impact on harming environment. While many studies have confirmed that the yield
increases with adopting SRI by field surveys, the impact of SRI on household income isstill debatable because SRI is a labor demanding method and may cause labor redistribution
within a household. This study assesses the impact of SRI on the yield, household income,expenditure and caloric consumption in Madagascar, taking into account the endogeneity
between farmer’s capacity and adapting technologies. The authors collect the data forsmall-scale rice producing households in Alaotra-Mangoro region on Madagascar central
highland in 2014 and 2017 by a face-to-face questionnaire survey. The authors find that the
adoption of at least one component of SRI has no significant impact on the rice yield,
income, expenditure and caloric consumption of households on average compared withthem that adopt none of the SRI components, taking account of the endogeneity oftechnology adoption. This study applies Propensity Score Matching (PSM) to take accountof the endogeneity. Then, comparing mean variables with using fertilizer by using PSM, theauthors confirm the positive impact on yield by plot level. However, because households
can’t adopt both SRI and the use of fertilizers for all plots, no significant difference isobserved in household income and expenditure. The findings suggest that a combination of
SRI with fertilizer inputs may increase yield significantly, if more farmers in the area start
using fertilizers in the future. Provision of technical SRI training alongside sales offertilizers is crucial. However, it is needed to conduct further research in our study site to
explore the impact on the household adopted all four of the SRI components which is more
effective, and long-term effects of SRI.
Keywords system of rice intensification (SRI), Madagascar, propensity score matching(PSM), impact assessment, technology adoption, small-scale rice farmers

INTRODUCTION
Sustainable agriculture that reduces environmental load and increases food production has been
attracting attention in recent years. System of Rice Intensification (SRI) is one of such a sustainableagriculture that has been drawing attention. This study focuses on the impact brought about by theuse of SRI in the Republic of Madagascar, the birthplace of SRI.
Madagascar is in Sub-Saharan Africa where population is growing rapidly, and is a major
producer of rice, its staple food. While most of its citizens engage in agricultural activities, thecountry suffers from low rice productivity and depends on imports for approximately 10% of its
consumption. Poverty rate in rural areas is quite high at 78%. Improved rice productivity is
considered to be a contributing factor towards poverty reduction in Madagascar.
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SRI is a rice cultivation method developed in 1993 by Father Laulanié and is based on his
observations of local farming methods as well as his own cultivation experiments (Stoop et al.,2002). SRI is practiced in many countries, particularly developing countries, thanks todissemination activities led by Norman Uphoff and others.
SRI is not a single package but rather a system that combines principles for transplantation as
well as soil and water management, does not require fertilizers and other exogenous inputs, and is
expected to promote tillering in rice plants and increase yield. The following four practices are
considered to be central principles of SRI in many areas where SRI is practiced (Noltz et al., 2012):(1) The use of young seedlings: transplanted within 15 days after germination (care must be
taken to ensure roots are not damaged), (2) Single seedling transplanting: A single seedling istransplanted per hill, (3) Planting at wider spacing: planting at 20cm × 20 cm spacing, (4)Intermittent irrigation: dry the soil moderately instead of ponding at all times. However, ensure thatsoil remains moistened.
While income from rice cultivation due to improved productivity is expected to increase,results vary by regions in terms of the impact of SRI on household income of farmers (Berkhout etal., 2015).
In East Timor, impact of SRI is observed with endogeneity of the adoption of agricultural
technology taken into account. As a result of taking endogeneity into account, SRI was found tohave an effect on the yield increase, but the difference in income between farmers who adopted
SRI and farmers who did not was quite small (Noltze et al., 2012). Similarly, a study thatconsidered endogeneity in Indonesia found that SRI increased yield but did not affect the income of
farmers. This was because the time previously spent by farmers to earn non-agricultural income
was now being spent on the labor required for rice cultivation. (Takahashi and Barret, 2013).
Another study found that SRI increases yield in areas without an irrigation facility but does not
improve income (Alem, 2015).
The impact of SRI on yield varies by region. On the other hand, improved agricultural
productivity affects household budget in various aspects. This includes an increased consumption
at home by farmers and consumption of food with higher nutritional value due to improved income(Pandey et al., 2016). In India, one study has found that farmers who adopted SRI are purchasing
insurance and consuming food with higher nutritional values (Singh et al., 2017). However, no
study has assessed its impact on expenditures and consumption while taking endogeneity into
account.
Madagascar is the origin of SRI, and previous studies have attempted to find a correlation
between SRI and rice yield as well as identify components of SRI that are crucial in increasing theyield (Barison and Uphoff, 2011; Tsujimoto et al., 2009). Another study has investigateddetermining factors that leads to the adoption of SRI as well as inhibiting factors (Moser andBarrett, 2003). On-site surveys have shown that SRI is effective in improving yield compared to aconventional farming method (Barrett et al., 2004, Barison and Uphoff, 2011).
While several studies have investigated factors associated with an adoption of SRI and factorsthat cause an increase in yield, few studies have focused on the impact of adoption of SRI on
farmers in Madagascar, and as far as the author is aware, a study on such an impact that takes
endogeneity of the technical adoption into account is particularly lacking.
OBJECTIVE
The objective of this study was to estimate the impact of SRI on the improvement of productivity
and livelihood of farmers in central highlands of Madagascar. Impact of SRI on the welfare of ahousehold is elucidated through a survey on the household income of farmers as well as theirexpenditure and food consumption.

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METHODOLOGY
Two communes, Ampitatsimo and Ilafy, located in Ambatondrazaka District in the AlaotraMangoro Region of Madagascar, were chosen as study sites. Irrigated area by Lake Alaotra islocated 240km northeast of the capital Antananarivo at 800m above sea level, and its climate is atropical highland climate. Rice cultivation and zebu cattle grazing have been practiced in the region
since the 19th Century (Yokoyama and Sakurai, 2014). Rice production in Lake Alaotra Region isamong the largest in the country and includes District PC15, one of the large-scale irrigated ricecultivation districts from the French colonial era (Fujiki, 2015). Rice cultivation period is long andlasts five to six months, and rice is usually grown once a year.
Fukuda (2015) investigated characteristics of SRI farmers in Ambatondrazaka District.
Farmers in this area combined technologies per plot with respect to varieties, transplantation, and
SRI. SRI was utilized in combination with the conventional practice. Risk preference also
influenced the decision of technologies. Risk-loving husband were more likely to adopt SRI. On
the other hand, more risk-aversive wives tended to choose conventional varieties and sort seeds.
Survey on an Introduction of SRI
A team led by Professor Sakurai of the University of Tokyo conducted a survey of Ambatondrazaka
District in 2014. Survey method is discussed below (Fukuda, 2015). Ampitatsimo consists of eightvillages (fokontany), and Ilafy consists of twelve villages. Average population per village wascalculated by dividing the total population of the commune by the number of villages, and four
villages were selected from Ampitatsimo and six from Ilafy. 40 rice farmer households wererandomly selected from each village (for a total of 400 households), with whom a face-to-facequestionnaire survey was conducted. The survey covered a broad range of topics including
socioeconomic attributes, income, food expenditures of farmers, the use of inputs at a plot level,
adoption of the technology, and yield, and it was conducted twice from May to June in 2014 andagain August 2014.
Number of plots managed by farmers totaled 1,337 plots, of which 732 plots were rice paddies
where rice was being cultivated. Surveyed farmers also participated in risk experiment in order tomeasure their risk preference.
335 households and 646 plots were used as survey data after removing missing values andoutlier data. Data from farmers who could not respond during the second survey period, farmers
whose responses were insufficient, and farmers whose number of cultivated plots increased
between the first and second survey periods were removed.
Survey on Knowledge on SRI and Decision on Its Implementation
Additional survey was conducted in December 2017 to clarify the path of SRI dissemination andthe state of its implementation. A semi-structured interview was conducted with eighteen farmer
households that has partially adopted SRI components, nine households who has not adopted any
SRI components from the previous survey. Additionally, the interview was conducted with two
agricultural bureau staff at the surveyed district, one head of the irrigation association, and one
Japanese specialist staff.
Analysis Framework and Method
Average treatment effect on the treated (ATT) is used to measure the difference of the average
between SRI farmers (i.e. treated group) and non-SRI farmers (non-SRI group) (Wooldridge, 2010).
(1)

Where yi1 shows the results for treated group, and y0i shows the results for control group. InⒸ ISERD

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this study, y is defined as the income of an SRI farmer or a yield from an SRI plot. Additionally, i is
the identification number assigned to each farmer. Technology is adopted when Di=1 andtechnology is not adopted when Di=0. Since yi1 and y0i cannot be measured at the same timeagainst i-th farmer, E(y0i │ Di=1) is replaced with measurable data from a non-SRI farmer.
Typically, a difference in farm management capability and motivation is assumed between SRI
farmers and non-SRI farmers, and such a difference causes bias in the results. Propensity Score
Matching (PSM) is used to address the bias from replacement (Rosenbaum and Rubin, 1983).
PSM assumes that an adoption of SRI is determined by an observable variable. If the adoption
is determined by an observable variable, the following equation can be derived.
(2)

Where p(xi) shows a probability that SRI is used under observable variable x.
(3)

PSM requires another assumption. Covariance of SRI farmers and non-SRI farmers need togreatly overlap. In another words, 0<p(xi)<1 needs to be satisfied. The following equation isderived from Equation (1).
(4)

From the above equation, the impact of SRI can be evaluated while taking endogeneity into
account. However, in order to minimize the estimation error of PSM, inclusion of every variableassociated with SRI adoption is recommended. If a variable that is not observed affects the
adoption of SRI, a bias may exist in the ATT result as well. Methods for matching treatment groupand control group includes nearest-neighbor matching, stratification matching, radius matching,and kernel matching, among others (Wooldridge, 2010). A matching method that minimizes thepseudo-coefficient of determination and error after estimation was chosen.
Factors that determine SRI adoption were analyzed in order to calculate aforementioned
propensity scores. Farmers presumably combine agricultural technologies independently for eachplot. Therefore, propensity scores were calculated for each plot. Logistic regression was used to
calculate propensity scores.
(5)

Where y is adoption of the technology (y＝1: SRI plot, y＝0: others), β0 is slices, and xk isvariable pertaining to adoption.
Hypotheses
This study asks two research questions: "How does SRI technology affect rice yield" and "howdoes SRI affect farmers?".
A pair of hypotheses are validated. First, fields where SRI is implemented produce greater
yields compared to non-SRI fields. Second, an increase in rice yield leads to an increase in riceincome, resulting in an overall increase in income for the household of the farmer. Over the courseof validating hypotheses, any changes in expenditure and personal caloric consumption are also
noted even when the income of farmers who has adopted SRI has not increased.
RESULTS AND DISCUSSION
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For analysis, an SRI plot is defined as a plot where at least one of the components ((1) Use ofyoung seedlings within 14 days after sowing, (2) Single seedling transplanting, (3) Transplanting
by spacing of at least 20cm, (4) Intermittent irrigation) is adopted because farmer adapting allcomponent is very few. A farmer is identified as an SRI farmer if the household practices SRI in atleast one of its cultivated plots.
Table 1 The results of a comparison based on whether SRI adaptation by plot level
Variable
Cultivated area (ha)Dummy for PC15
Presence of an irrigation facility
Dummy for land ownership
Dummy for land fertility
Weeding frequency
Dummy for transplantation
Dummy for the use of commercial varieties
Seed usage (kg/ha)
Total chemical fertilizer usage (kg/ha)
Total organic fertilizer usage (kg/ha)
Distance to the plot (min)Yield (t/ha)
Rice productivity per person (kg/person)
Revenue from rice (1,000Ar/ha) …A
Fertilizer cost (1,000Ar/ha)
Pesticide cost (1,000Ar/ha)
Herbicide cost (1,000Ar/ha)
Seeds cost (1,000Ar/ha)
Land improvement cost (1,000Ar/ha)
Hired labor cost (1,000Ar/ha)# non-hired laborers (man-days/ha)
Cost of rice cultivation (1,000Ar/ha) …B
Cost incl. non-hired labor (1,000Ar/ha) …B’
Income from rice (1,000Ar/ha)… (C = A – B)
Profit from rice (1,000Ar/ha) … (D = A - B’)Observed
Note: *** p<0.01, ** p<0.05, * p<0.1

SRI ave.
0.60
0.35
0.58
0.64
0.10
1.06
0.96
0.71
147
1.20
1,149
24.1
2.91
19.3
2,120
51.6
6.01
6.677
111
61.4
272
289
509
1,379
1,611
742
112

Non-SRI ave.
0.75
0.14
0.64
0.64
0.15
0.86
0.61
0.78
158
1.17
734
40.5
2.34
28.5
1,703
36.9
4.25
6.675
103
47.6
172
190
371
942
1,333
762
521

Total ave.
0.72
0.18
0.63
0.64
0.14
0.89
0.67
0.77
156
1.17
810
37.6
2.44
26.9
1,777
39.5
4.57
6.676
104
50.0
190
207
395
1,019
1,382
758
633

SRI-Non-SRI diff.
-0.15
0.20***-0.0550.0018-0.0520.21***
0.35***
-0.68
-12
0.033
415*
-16.4**
0.57***-9.23
417***
14.7
1.76*
0.002
8.32
13.8
100***
99**
139***
437***
278*-20.2

Table 1 shows the results of a comparison based on whether SRI is adopted or not at a plotlevel. Significant differences between SRI plots and non-SRI plots were observed for presence ofPC15, weeding frequency, transplantation, amount of organic fertilizer used, distance from home toplots, cost of hired labor, and number of labor days worked by non-hired laborers.
Ratio of transplantation is higher among SRI plots since three of the SRI components(excluding intermittent irrigation) are techniques related to transplantation. Intermittent irrigation
requires an irrigation facility, and the ratio of intermittent irrigation and the ratio of District PC15
was greater for SRI plots. Weeding work was performed more often in SRI plots due to intermittent
irrigation. Greater number of organic fertilizers used in SRI plots was due to recommendations
being made towards the use of organic fertilizers at the time of SRI adaptation. Greater hired andnon-hired labor in SRI plots was also consistent with previous studies, which confirmed thepossibility that SRI is a more labor-intensive farming method.
Yield increased by 0.57 (t/ha) in SRI plots. At the same time, cost incurred by rice cultivation
also increased. Based on the market price for Alaotra-Mangoro Region from 2014, price per kg of
rice was assumed to be 728 (Ar/kg). Rice income per ha was greater in SRI plots at 10%
significance level. Cost of non-hired labor was calculated by assuming the mode of hired labor cost
as the employment wage within the area. Significant difference was not observed in profit
calculated after including a non-hired labor cost. Significant difference was not observed for riceproductivity per person (kg/person), and the adoption of SRI in the area has not improved labor
efficiency. Additionally, farmers who adopted SRI were accounted for 23% of the total households,
and average yield was 2.32 (t/ha).

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Impact of Each Variable on the Adoption of SRI
The impact of each variable on the adoption of SRI at a plot level, calculated by using a logit model
which can estimates probability to adapt the SRI. Variables that had a negative impact on the
adoption of SRI were cultivated area, number of family members, female family head, distancefrom home to the field, and the commune in which the farmer lives. Variables that had a positive
impact on the adoption of SRI were availability of irrigation, PC15 dummy, number of years ofeducation, number of traders the farmer knows, and knowledge on intermittent irrigation.
Estimated ATTTable 2 shows the estimated ATT. At a plot level, yield was greater in SRI plots than non-SRI plots
and income, but its difference was not significant. Both hired and non-hired labor were greater in
SRI plots. In particular, non-hired labor was 113 (man-days/ha), which was significantly larger at
10% significance level and showed a much greater need for labor in SRI plots. No significant
differences were observed for other variables, which show that technologies other than adopted SRI(e.g. fertilizer inputs) do not make a difference between SRI and non-SRI plots. At a household
level, no significant difference was observed in yield between SRI and non-SRI farmers. Income
from rice and income for the entire household were greater among SRI farmers, but no significant
differences were observed. Income by means other than labor was the only variable where asignificant difference was observed between SRI and non-SRI farmers; SRI farmers weregenerating a greater amount of income through remittance and land lease. These results indicatethat the adoption of SRI has not had an impact on yield and income in the area at a household level.
Table 2 Estimated results by ATT
Plot level
Variable

ATT result (SRI plots - non-SRI plots)

Standard error

Yield (t/ha)
Cost of rice cultivation (1,000Ar/ha)
Income from rice (1,000Ar/ha)
Profit from rice (1,000Ar/ha)# non-hired laborers (man-days/ha)
Hired labor cost (1,000Ar/ha)
Total chemical fertilizer usage (kg/ha)
Total organic fertilizer usage (kg/ha)
Seed usage (kg/ha)
Observed

0.37
29.2
243
-95.4
113*
44.4
-2.05
113
-9.59
630

-0.32
-65
-153
-212
-70.0
-43
-2.48
-338
-17.2
-

ATT result (SRI farmers -non-SRI farmers)

Standard error

Household level
Variable

Average yield for a household (t/ha)
0.39
0.39
Household income (1,000Ar)
601
609
Income per person (1,000Ar/person)
77.8
126
Income from rice cultivation (1,000Ar)
244
472
Income from crops excl. rice (1,000Ar)
-36.9
104
Income from self-employment (1,000Ar)
-14.3
184
Non-agricultural income (1,000Ar)
-1.99
122
Income from livestock (1,000Ar)
101
87
Non-labor income (1,000Ar)
309***
130
Food expenditure (1,000Ar / week)
1.16
2,41
Total expenditure (1,000Ar/ month)
12.4
24,7
Calorie consumption per person
173.3
-30.2
(kcal/day)Observed
325
Note: *** p<0.01, ** p<0.05, * p<0.1
Plot level uses Kernel matching was used as a matching method. Bandwidth was 0.01, and resampling was iterated
900 times by bootstrap method to obtain a standard error.
Household level uses Radius matching was used as a matching method. Radius was 0.06.
Observed number is different from Table1 because some date is not suitable due to missing parameter.
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Knowledge on SRI and Decision on its Implementation
Fig. 1 shows the timing in which farmers became aware of SRI, and shows components regarded asa part of SRI technology in the studied area. While there were some differences in terms of therecognized techniques that constitute SRI, all 27 farmer households interviewed knew about SRI.
Diverse timing in which farmers became aware of SRI and various paths through which SRI
disseminated indicate that the word "SRI" itself is widely known in the studied area. However,institutions such as JICA and the local agricultural bureau have also disseminated othertechnologies, and it is quite possible that farmers confuse these technologies with SRI.
Highest number of farmers that learned about SRI was recorded in 2000, a year in which
extension workers of an NGO have disseminated the SRI technology in several communes.
Importance of water management was recognized in many households. Many farmers also felt theimportance of using relatively innovative technologies, including the use of chemical fertilizers andpesticides and the use of a rotary weeder. While many farmers said that regular planting and row
planting are important, only three respondents saw increased spacing between rows (a uniquefeature of SRI) as important, four saw single seedling transplanting as important, and two saw theuse of young seedlings as important.
Results suggest that farmers in this area may be recognizing new technologies also as "SRI",in spite of the fact that they are not a part of the four major components that constitute SRI.
0

Number of responses
5
10

15

Adoption of intermittent irrigation
Organic fertilizers
Use of chemical fertilizers
Liquid fertilizers
Pesticides
Regular planting
Row planting
Interrow spacing at or over 10 cm
Interrow spacing of 20 – 25 cm
Single seedling transplanting
Use of young seedlings
Transplantation with care
Use of a rotary weeder
Leveling
Use of good seeds
SRI

Non-SRI(N=27)

Fig. 1 Component techniques of SRI(N=27)

Fig. 2 Period in which farmers know about SRI

Impact of Fertilizer Inputs
Soil fertility in the studied area is low, and phosphorus deficiency is particularly evident (JICA,
2017). For this reason, widening the spacing between seedlings only widens the space and is likely
to reduce yield. In the farmer’s interview, some farmers indicated that farmers also viewed therelationship between land fertility and seedling spacing as important. Fertilizer inputs itself isassumed to contribute greatly to yield improvement. In addition, if seedlings are planted at wider
spacing while fertilizers are applied, merits of SRI such as seed savings and an increase in thenumber of tillers can be expected.
Therefore, differences in yield and income due to whether fertilizer are applied or not as well
as a combination of fertilizer inputs and SRI were verified using data from 2014.
Table 3 shows the results. Estimation after matching shows an increase in average yield due tofertilizer inputs. However, a significant difference in income was not observed due to an increase infertilizer cost and hired labor cost. When fertilizer inputs were combined with SRI, yield increased
by 0.61 (t/ha). While the cost of rice cultivation increased, income per ha also increased due to asignificant increase in yield. However, income did not increase when non-hired labor wasconverted to cost due to an increase in the amount of non-hired labor. At a household level, nosignificant differences were observed in rice yield and thus income from rice cultivation, and no
significant differences were also observed in other incomes.
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Table 3 Impact of fertilizer inputs
by plot
Variable
Yield (t/ha)
Cost of rice cultivation (1,000Ar/ha)
Income from rice (1,000Ar/ha)
Profit from rice (1,000Ar/ha)
Seed usage (kg/ha)
Cost of hired labor (1,000Ar/ha)# non-hired laborers (man-days/ha)
Observed
per household

Estimation by ATT
Fertilizer (Fertilizer = 297)
Fertilizer + SRI (Fertilizer + SRI = 61)
0.37**
0.61***
130***
145***
138
302**
53.0
66.1
20.1*
20.1
36.7**
86.0***
28.4
78.6*
630
630
Estimation by ATT

Variable
Fertilizer (Fertilizer = 181)
Fertilizer + SRI (Fertilizer + SRI = 50)
Household income (1,000Ar)
82.6
588
Income per person (1,000Ar/capita)
5.29
136
Income from rice cultivation (1,000Ar)
197
416
Average yield for a household (t/ha)
0.26
0.33
Income from crops excl. rice (1,000Ar)
11.0
34.0
Income from self-employment (1,000Ar)
-123
-112
Non-agricultural income (1,000Ar)
28.9
47.8
Income from livestock (1,000Ar)
0.875
91.1
Non-labor income (1,000Ar)
-31.5
111
Food expenditure (1,000Ar / 1 wk)-0.361-0.098
Total expenditure (1,000Ar/ month)
16.9
-16.8
Calorie consumption per person (kcal/day)
17-37
Observed
325
325
Note: *** p<0.01, ** p<0.05, * p<0.1
By plot level uses radius in radius matching for fertilizer use was 0.04, and radius for fertilizer + SRI was 0.01
Per household level uses radius in radius matching for fertilizer use was 0.05, and radius for fertilizer + SRI was 0.06.

As a result, the difference in household income due to fertilizer inputs was not significant.
This result was also the same for a case in which the use of fertilizers and SRI were combined.
Lack of difference in yield and income at the household level may be due to the fact that thetechnologies were not being applied across all cultivating plots.
Comparison of average yield difference between years 2016/2017 and 2013/2014 showed areduction in average yield for 2017 by 0.68 t/ha. This is likely due to a dearth of rainfall in
2016/2017, which led to a poor harvest for the year with a significant reduction in average yield.
Weather conditions such as rainfall were not controlled, but they suggested that an increase in yield
between 2014 and 2017 was unlikely.
CONCLUSION
This study investigated the impact of SRI on yield and living expense among rice farmers in two
communes in Ambatondrazaka District of Madagascar. In the analysis, yield, household income,and expenditure were compared by using data obtained by on-site surveys. PSM was used toaccount for selection bias and compare average yield between SRI and non-SRI plots, whichshowed that yield was greater in SRI plots but without a significant difference. Improvement in riceincome due to an adoption of SRI was not observed. While the household income was greater for
SRI farmers, there were no significant differences between two groups. Differences due to SRI
adoption were not observed with regards to a week's worth of food expenditure and expenditure permonth by the farmer. Similarly, consumed calories were calculated based on food consumption by
farmers, but no difference due to the adoption of SRI was observed.
Interview results from 2017 showed that the term "SRI" is widely known among farmers.
However, details of the technology recognized by farmers varied greatly, which implied that SRI is
a technology whose name is well-known, but its details are not accurately known.
Considering low soil fertility of the studied area, wider spacing between seedlings may reduceyield. On the other hand, high yield may be achieved by improving soil fertility through fertilizerⒸ ISERD

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inputs and adoption of SRI. Survey results from 2014 also confirmed that yield increases when SRI
is combined with fertilizer inputs. In this case, cost incurred to cultivate rice increased at a plotlevel, but income also increased, thereby indicating the importance of combining fertilizer inputs
with SRI components. Even in this case however, because households were unable to adopt both
SRI and the use of fertilizers for all plots, no significant difference was observed in income fromrice cultivation and household income.
In the future, a combination of SRI with fertilizer inputs may increase yield significantly, if
more farmers in the area start using fertilizers. Provision of technical SRI training alongside salesof fertilizers is crucial.
Future Research
Among farmers surveyed in this study, only one household adopted all four of the SRI components.
In the analysis, farmers who have adopted some of the SRI components were defined as farmers
who have adopted SRI. SRI is considered to be most effective when all of the components are
adopted (J-SRI, 2011). For this reason, any area nearby the site for this study where SRI is widelypracticed may have adopted all components of SRI and thus increased the yield. In addition,comparison per SRI component was not possible due to the sample size, and an identification ofcomponent(s) that is important for the study site could not be conducted.
This study did not consider the number of years through which SRI is continually practiced.
One study has suggested that farmers who have continued to practice SRI for a number of years areaccustomed to the technology and thus able to improve their productivity (Moser and Barrett 2003).
An analysis that accounts for the number of continuously practiced years would be important inmeasuring long-term effects of SRI.
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Research article
erd

Effects of Lead and Other Metals from Historical Smelting
on Sustainable Fruit and Vegetable Cultivation
BARRY NOLLER*
The University of Queensland, St Lucia, Australia
Email: b.noller@uq.edu.au

FIONA HENDERSONThe University of Queensland, St Lucia, Australia
Received 31 January 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract Wollongong, located in the Illawarra region of NSW Australia, contains theindustrial complex of Port Kembla. Lead in Port Kembla soils, ~2.5 km from a former
copper smelter (1908-2003), have exceeded soil contamination guidelines for human health(HIL) and ecological (EIL) investigation levels. Previous studies regarding heavy metal
contamination from the industrial complex, do not include comparisons to HIL and EIL
guidelines. This study re-examines the risk of legacy (historic) heavy metals in urban soils
to residents in proximity to the Port Kembla industrial complex. This was accomplished byreviewing: (i) resolution of heavy metal dispersion data from the copper smelter, in historicsoil concentration data (n=95 top soil samples) collected by Jafari (2009) and reviewed by
Noller (2020a); (ii) providing a new comparison of historic percentile data to current
Australian soil contamination guidelines (NEPC, 2013) and German atmospheric pollutant
guidelines; and (iii) re-evaluating treatments to soil data by Jafari (2009), in the context of
bioaccessibility and bioavailability to humans and plants. At 75th percentile, arsenic,
cadmium, copper, lead and zinc concentrations exceeded HIL Level A guidelines. Whendetection limit values (52 out of 95) were removed (n=22 samples), median cadmium
concentrations exceeded HIL Level A guidelines. Dietary exposure to cadmium, lead, zincand copper is a risk to residents through the consumption of vegetables grown in urban
gardens in proximity to the Port Kembla industrial complex. Copper in vegetables sampledfrom soils in the vicinity of the Port Kembla copper smelter was greater in comparison to
sampling completed at other smelter sites. Port Kembla urban garden vegetables showed
exceedance of food guidelines for both cadmium and lead, highlighting the health risks ofgrowing vegetables in proximity to industrial areas.
Keywords heavy metals, arsenic, smelting, sustainable, fruit and vegetable cultivation

INTRODUCTION
The Wollongong local government area (LAG) is located in the Illawarra region of New South
Wales (NSW), Australia (Fig. 1), 80 km south of Sydney. The Wollongong LAG contains theindustrial complex at Port Kembla; a feature which has remained in place for over 100 years(Chiaradia et al., 1997; Jafari, 2009). A copper smelter, formerly Southern Copper ERS Ltd (SC in
Fig. 1), commenced operations at Port Kembla (1908-2003) and demolished in 2014. A
considerable body of literature exists on the nature, extent and distribution of heavy metals andarsenic in soils in Wollongong and Port Kembla (Noller, 2020a). The current Australian guidelines
for human health (HIL) and ecological (EIL) investigative levels are risk-based approaches used to
examine and interpret soil, air, water and food environmental data. Existing guidelines (HIL and
EIL) had yet to be implemented at the time of previous data collection and analysis (Noller, 2020a).
Previously, lead (Pb) was mainly investigated at Port Kembla, yet cadmium (Cd), zinc (Zn), copper(Cu), and arsenic (As) also exceeded Australian National soil contamination guidelines (HIL and
EIL) (NEPC, 2013; Noller, 2020b). In the absence of Australian air pollutant guidelines, GermanⒸ ISERD

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air pollutant controls (TA LUFT standards) for metal fallout were used (TA LUFT, 1990, 1999;
Noller, 2020b).

Fig. 1 Location of the historical Port Kembla industrial complex, including the southerncopper smelter (SC) and other sampling sites (Chiaradia et al., 1997)
OBJECTIVE
The objectives of this study are to re-examine and evaluate the human-health risks to residents inthe proximity to the Port Kembla industrial complex, based on historic heavy metal and As
concentrations in soil.
METHODOLOGYThis study aims to follow three methods of re-examination and analysis: (i) to review the resolutionof heavy metal and As dispersion data from the copper smelter, in historic soil concentration data (n=95
top soil samples) collected by Jafari (2009) and reviewed by Noller (2020a); (ii) to provide a newcomparison of historic percentile data to current Australian soil contamination guidelines (NEPC, 2013)
and TA LUFT (1990, 1999) German atmospheric fallout standards; and (iii) to re-evaluate treatments tosoil data by Jafari (2009), in the context of bioaccessibility and bioavailability to humans and plants.
The Jafari (2009) study measured the total concentration of 37 elements in soil samples (n=95) by
XRF-spectrometry. Soil samples were treated with 0.1M hydrochloric acid extraction andethylenediamine tetra acetic acid (EDTA). Data from Jafari (2009) was not previously evaluatedfor human health or ecological risks, however extraction methods in Jafari (2009) are an analog toreflect human bioaccessibility of metals and As in soils (HCl acid extract similar to stomach acid) andindicate plant uptake (EDTA extract). The detection limit for Cd was 10-20 mg/kg (Jafari, 2009)
resulting in only high values of Cd being compared with guidelines (Noller, 2020a). This study reexamines data from Jafari (2009) and Noller (2020a) and compares percentile values of As, Cd, Cu,eⒸ ISERD

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Pb and Zn against soil guidelines (NEPC, 2013), to inform a risk assessment of potential resident
exposure from historic smelter emissions.
RESULTS AND DISCUSSION
Summary results are given in percentile values in Table 1 for metals and As in soil (mg/kg), andTable 2 for mean percent extractable metals and arsenic in soil at Port Kembla.
Table 1 Percentile values for metals and arsenic in soil (mg/kg) at Port Kembla
Maximum

HILa
Level A

EILb
Urbanresidential

535

1999

1000

30-230

220

432

2833

7000

25-1300

14 ±24

7

12

183

100

50-10052

89 ±189

29

39

840

20

-

3

178 ±479

64

126

667

300

270-1100

Metal/
metalloid(n=95)

No.<
ValuesMean (SD)

Copper0

ZincMedian75th
percentile556±12461612

373 ±417

Arsenic1

Cadmium
Lead

Source a. HIL Level A is for urban residential with garden (Noller,2020b); and b. EIL Urban-residential includes
public open spaces for both invertebrate and plant species protection level of 80% (approximated using 75% data) withupper and lower levels combining added contaminant limit with background concentration. The EIL for Cd is notavailable. Site specific measurements can be undertaken to derive a Cd EIL (NEPC, 2013; Noller, 2020b), but not forthis study.

Examination of percentile values (Table 1) shows that concentrations of As, Cd, Cu, Pb andZn exceeding HIL Level A investigation levels for residential soils are all greater than 75th
percentile values. When the detection limit values of Cd (52 out of 95) were removed, 22 soil
concentrations exceeded HIL Level A at their median (50th percentile) value.
Jafari (2009) noted a positive correlation between Cu (P < 0.001), As (P < 0.001), Pb (P <0.001) and Zn (P < 0.01) concentrations and distance from the smelter stack. Concentrations in soil
in proximity (< 1.5 km) to the smelter stack contained higher amounts of total Cu (>1500 mg/kg)
and As (> 10-15mg/kg), Pb (> 150-200mg/kg) and Zn (> 400-600mg/kg) (Jafari, 2009). Highest
concentrations of As, Cd, Cu, Pb, and Zn were attributed to samples from slag heaps (Jafari, 2009).
Contamination of heavy metals and As in soils surrounding the Port Kembla smelter, range at a
distance of 1-4km, but higher concentrations are observed <1km from the smelter stack.
Percentile values depicted in Table 1, shows that except for Cu, 75th percentile values formetals and As do not exceed EIL standards. Readers should note that there is no current EIL
guideline for Cd. Some effects on terrestrial species in garden soil from Cu may be expected as theEIL urban-residential guideline is exceeded for concentrations greater than median (Table 1).
Single extraction technique data used to determine 0.1M Hydrochloric acid and 0.05M EDTA
concentrations of elements (Table 2) show that Cu, Pb and Zn concentrations decreased withincreasing distance from the stack (Noller, 2020a). The heavy metal and As extraction techniqueof 0.1M hydrochloric acid, can be utilized as a gastro-intestinal simulation, to predict humanbioavailability (Table 2). More accurately, 0.1M hydrochloric acid extractable metals and arsenic
provides an indication of their bioavailability during the gastric phase (Table 2); however, thismethod likely overestimates their bioaccessibility, as the intestinal phase (functions at ~ pH 7
conditions) is not considered (Noller, et al. 2017). It is important to distinguish that the humanintestine is where heavy metal and As absorption takes place, while the stomach (gastric phase) is
where solubilization of food (heavy metals and As) occurs. The 0.05M EDTA extractableconcentrations of heavy metal and As represent the relevant concentrations of plant uptake fromsoil (Table 2).

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Table 2 Mean percent extractable metals and arsenic in soil at Port Kembla
Extractant

Arsenic (%)

Copper (%)

Lead (%)

Zinc (%)

Cadmium (%)

0.1M HCl

35.7

22

28

43

4.27

0.05M EDTA

42.9

32

37

33

4.5

The mean 0.1M hydrochloric acid extractable Pb concentration (Table 2) of 28.0% in
Wollongong soil indicates that bioaccessibility is low (compared with < 100%). Thisbioaccessibility (BAc) level is similar to soil at other mining centres in Australia (Noller et al.,2017). The HIL Level A 300 mg/kg for Pb and 0.1M hydrochloric acid extractable Pb is equivalent
to a site-specific level of 1,071 mg/kg (BAc-adjusted site-specific concentration = HIL A (300mg/kg) / 0.28), i.e., by assuming that the bioaccessibility is conservatively 28.0%. The HIL Level
A 100 mg/kg for As and 0.1M hydrochloric acid extractable As is equivalent to a site specific levelof 280 mg/kg (BAc-adjusted site specific concentration = HIL A 100 mg/kg/ 0.36); The HIL Level
A 6000 mg/kg for Cu and 0.1M hydrochloric acid extractable Cu is equivalent to a site specificlevel of 27,300 mg/kg (BAc-adjusted site specific concentration = HIL A 6000 mg/kg/ 0.22), i.e.
assuming BAc is 22.0%. If ‘bioaccessibility-adjusted’ concentration is utilized, no exceedances of
HIL A from metals and As in soil occurs. The HIL Level A 20 mg/kg for Cd and 0.1M
hydrochloric acid extractable Cd is equivalent to a site-specific level of 468 mg/kg(bioaccessibility-adjusted), assuming bioaccessibility is 4.27%. This shows ‘BAc-adjusted’
concentrations (n=22) do not exceed HIL A for Cd.
Table 3 summarizes and compares historical Pb and Cd (µg/m2.day) fall-out data at Port
Kembla and other Wollongong sites, with fallout data from the electrolytic refinery site at Hobart,
Tasmania (located 1600 km south of Sydney, NSW; Fig. 1). Converting the measured fall-out inunits of μg/cm2.year to μg/m2.day (Table 3) enabled a comparison of historical data for Pb and Cd
with current German dust metal and metalloid deposition guidelines (TA LUFT, 1990 and1991). A
retrospective evaluation of fallout data compared to German guidelines informs on the significanceof historical Pb and Cd deposition in soil. Data in Table 3 shows: (i) Lead at sites near Port Kemblasmelters exceed TA LUFT ‘protection of human health and crop land integrity’ and ‘Grassland
integrity’ (May 1981) for fallout monitoring during the 1970s - 1980s; and (ii) Cadmium, at all sites
at Port Kembla, exceed TA LUFT ‘Protection of human health’ guideline by 47 times at a value of
94μg/m2.day except when <5.5μg/m2.day. Contour diagrams of dust fall-out in Archibold and Crisp(1983) showed that Pb deposition extended across the north central part of the Wollongong study
area in September 1980, with peak fallout occurring at the smelter, which subsequently decreasedin April 1981. Table 3 shows the residents at this time could have been exposed (ingestion) toelevated Cd and Pb from fall-out.
Cd and Pb uptake from atmospheric fall-out, could have occurred in vegetable gardens, 1-2
km from smelter locations. Although current emission of Pb is not an issue in Wollongong forhuman health exposure from inhalation, it is possible that remobilization of Pb or Cd from surface
soil is an ingestion issue today, particularly for children. The historical record of Cd and Pb fallout
from the Port Kembla copper smelter and steelworks indicates the extent of dispersion of Cd andPb was real and likely resulted in direct exposure to residents or due to ingestion of garden
vegetables.
For ecological conditions soil organisms can be affected. Comparison of fallout levels of Cd
and Pb in Hobart suburbs from the electrolytic zinc refinery (Table 3) show emissions were lower
than for Port Kembla, but similar to Wollongong suburbs. Dietary exposure to Cd, Pb, Zn, Cu, andAs is a risk to human health through consumption of vegetables, especially in urban-residential
areas. The extent of Cu uptake in vegetables sampled from soils in the vicinity of the smelter at
Port Kembla was greater than at other smelter sites (Kachenko and Singh, 2006). Both Cd and Pb
in vegetables at Port Kembla exceeded Australian Food Standards maximum level (ML both 0.1
mg/kg fresh weight for Cd and Pb; (FSANZ 2016; Kachenko and Singh, 2006). This highlights theimportance of historical investigations and retrospective evaluations. This study reveals the risk ofheavy metal persistence in urban-residential soils near historic smelter operations. Local residentsⒸ ISERD108

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may be at risk from growing vegetables in soils not completely rehabilitated following
decommissioning of smelters.
Table 3 Summary of historical air fallout data for lead and cadmium at Port Kembla andWollongong, NSW and Hobart, Tasmania
Cadmium Mean±se(µg/m2.day)

Lead Mean±se(µg/m2.day)

Reference

Wollongong suburbs
Wollongong suburbs (2)<5.5

71.2 ±27.4

Beavington (1977)

September 1980 (13)-185 ±36.8

Crisp et al., (1984)

October 1980 (4)-725 ±323

Crisp et al., (1984)

November 1980 (9)Port Kembla
Port Kembla smelter/ works (5)-183 ±44

Crisp et al., (1984)

26.3 ±9.7

568 ±230

Beavington (1977)

September 1980(1)

-

1040

Crisp et al., (1984)

October 1980(1)

-

4870

May 1981(7)94 ±3.03760 ±109

Crisp et al., (1984)
Archibold and Crisp(1983)

Rural site
56km from SC smelter (1)Hobart suburbs

<5.5

24.7

Hobart suburbs (11)1.70 ±0.60

40 ±14

Electrolytic zinc refinery site (7)6.0 ±5.0

173 ±100

Site (n)Dust Deposition Guidelines
Cadmiuma
Leada

Beavington (1977)
Ayling and Bloom(1976)Ayling and Bloom(1976)

2

Protection of human healthb
Protection of crop land
integrityc
Protection of grassland
integrityc

100

TA LUFT (1990, 1999)

185
1900

Source a. Averaging Period 1 year; b .TA LUFT (1990); and c. TA LUFT (1999).

CONCLUSION
The total concentrations of heavy metals and As in 95 surface soil samples collected in 2009 as
percentile values provided better resolution of dispersion distance from the copper smelter at Port
Kembla. The comprehensive treatment of existing data by comparing historical data against current
guidelines was not previously possible until this study. Historical fallout data compared against
current heavy metal fall-out guidelines predicts past smelter emissions build-up in soil suggesting
potential risks to residents ingesting vegetables grown from contaminated urban soils.
ACKNOWLEDGEMENTS
The NSW EPA, Sydney NSW, Australia funded the literature review of lead and other heavy
metals in soil and roof dust in Wollongong and measures to manage any associated health risks.

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REFERENCES
Archibold, W.O. and Crisp, T.P. 1983. The distribution of airborne metals in the Illawarra region of New
South Wales, Australia. Applied Geography, 3 (4), 331-344, Retrieved from https://www.sciencedirect.
com/science/article/pii/0143622883900498
Ayling, M.G. and Bloom, H. 1976. Heavy metals analyses to characterize and estimate distribution of heavy
metals in dust fallout. Atmospheric Environment, 10 (1), 61-64, Retrieved from https://www.
sciencedirect.com/science/article/pii/0004698176902614?via%3Dihub
Beavington, F. 1977. Trace elements in rainwater and dry deposition around a smelting complex.
Environmental Pollution, 13 (2), 127-131, Retrieved from https://www.sciencedirect.com/science/article/pii/0013932777900970
Chiaradia, M., Chenhall, E.B., Depers, M.A., Gulson, L.B. and Jones, G.B. 1997. Identification of historicallead sources in roof dusts and recent lake sediments from an industrialized area: Indications from leadisotopes. Science of the Total Environment, 205, 107-128, Retrieved from https://www.sciencedirect.
com/science/article/pii/S004896979700199X
Crisp, T.P., Archibold, W.O. and Crisp, A.E. 1984. The use of wind direction data to predict pollution
dispersal around the Port Kembla industrial area, New South Wales. Australian Geographical Studies, 22(2), 243-260, Retrieved from DOI https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1467-8470.1984.
tb00632.x
Food Standards Australia New Zealand (FSANZ). 2016. Australia New Zealand food standards code Schedule 19 - Maximum levels of contaminants and natural toxicants. Australian Government, Canberra,
Australia, Retrieved from https://www.legislation.gov.au/Details/F2017C00333
Jafari, Y. 2009. Trace metal contamination of soils and sediments in the Port Kembla area, New South Wales,
Australia. MSc Dissertation, University of Wollongong, Australia.
Kachenko, G.A. and Singh, B. 2006. Heavy metals contamination in vegetables grown in urban and nearsmelter contaminated sites in Australia. Water Air and Soil Pollution, 169, 101-123, Retrieved fromhttps://link.springer.com/content/pdf/10.1007/s11270-006-2027-1.pdf
National Environment Protection Council (NEPC). 2013. National environment protection (Assessment ofsite contamination) measure. National Environment Protection Council, Canberra, Australia, Retrieved
from http://www.nepc.gov.au/nepms/assessment-site-contamination
Noller, N.B. 2020a. Literature review of the levels of lead and other heavy metals in soil and roof dust in
Wollongong and measures to manage any associated health risks. NSW Environment Protection
Authority, Sydney, Australia, Retrieved from https://www.epa.nsw.gov.au/-/media/epa/corporatesite/resources/community/literature-rreview-of-the-levels-of-lead-in-dust-in-wollongong.pdf?la=en&
hash = 6161419554B16FD0C6F89CA450ED051DBFB53A4A
Noller, N.B. 2020b. Environmental effects from contamination of agricultural soils via spraying and dust
application to crops and animals. International Journal of Environmental and Rural Development, 11 (1),69-74, Retrieved from https://iserd.net/ijerd111/11-1-11.pdf
Noller, N.B., Zheng, J., Huynh, T., Ng, J., Diacomanolis, V., Taga, R. and Harris, H. 2017. Lead pathways
study-air. Health risk assessment of contaminants to Mount Isa City. Mount Isa Mines Limited, Mount
Isa, Australia, Retrieved from http://www.mountisamines.com.au/EN/sustainability/Pages/LEADPATH
WAYSSTUDYPORTAL.aspx
Technische Anleitung zur Reinhaltung der Luft (TA LUFT). 1999. Technical instructions on air quality
control. Bundesministerium für Umwelt, Naturschutz und Reaktorsicherheit (Federal Environment
Ministry), Bonn, Germany, Retrieved from http://www.umweltbundesamt.deⒸ ISERD

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Research article
erd

Utilizing Lead Isotope Tracing to Investigate Sustainable
Agriculture Practice in the Burdekin Catchment, Australia
FIONA HENDERSON*The University of Queensland, St Lucia, Australia
Email: uqfhend1@uq.edu.au

BARRY NOLLER
The University of Queensland, St Lucia, Australia

TATIANA KOMAROVA
Queensland Health Forensic Scientific Services, Brisbane, Australia
Received 31 January 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract The Burdekin delta is the largest sugarcane producing region in Australia (85,000ha) and a major coastal output to the Great Barrier Reef (GBR). Run-off from cultivation
areas contain heavy metals from fertilizers, contributing to elevated Cd, Hg, and Pb inwaterways. Validating the efficacy of sustainable agriculture practice is necessary to
determine if current strategies protect ecosystems and uphold environmental standards. The
objective of this study is to utilize Pb isotope tracing (207/206Pb and 208/206Pb) and elevatedtrace-elements (Cd, Hg, and Pb) as a monitoring tool, to detect residual heavy metals fromfertilizers and alternative pollutant sources in the Burdekin catchment. Lead-isotope ratiosfrom dry-season samples of embankment soils/sediment (n=15, 2016, 2019) and water(n=35, 2016-2020), reveals sources of natural forest soils, cane soils (fertilizer enriched),
ambient dust, and historic coal fly-ash (Collinsville Power Station). Pb isotope
compositions and low levels of heavy metals (soil/sediment: TCd 0.11 mg/kg, THg 0.03
mg/kg and TPb 11.02 mg/kg; estuary: THg 0.011 μg/L and TPb 4.99 μg/L) indicate that
fertilizers applied to soils have minimal impact on Burdekin waterways during the dryseason, suggesting effective agricultural practice and sustainable irrigation control.
Keywords agriculture, sustainability, sustainable practice, lead isotope, source-tracing

INTRODUCTION
The GBR is the largest reef ecosystem on the planet (344,400 km2) and a World Heritage site
located off the coast of Queensland (QLD), Australia (Coggan et al., 2021). Land-runoff fromcoastal catchments can adversely impact the GBR (Lewis et al., 2021). Agricultural
mismanagement, (i.e. fertilizer overuse and uncontrolled irrigation run-off) contributes to water
quality risk through the accumulation of heavy metals in soil and remobilization to waterways(Table 1; Alengebawy et al., 2021; Coggan et al., 2021). In literature, research has conventionallyused elevated heavy metals to establish pollutant presence and Pb-isotopes to trace pollutant source
by providing a measure of geologic age (Table 1; Diaz-somoano et al., 2009; Lottermoser, 2009;
Alengebawy et al., 2021). Following ~10 years of sugarcane cropping, Rayment (2007) noted Cdand Hg were elevated in QLD cane soils. Davis, et al. (2008) detected sugarcane pesticides in
Burdekin waterways. Extended fertilizer use is known to degrade soil fertility and productivity(Ping et al., 2020). Fertilizer overuse burdens the environment, economic and social value of boththe GBR and the sugarcane industry (DAE, 2017). Sugarcane production is $1.33 billion AUD(gross); the Burdekin represents 31% or $4.12 million AUD (DAE, 2017). Aboriginal and Torres
Strait Islanders have maintained cultural ties to the GBR for ~ 60,000 years. There are over 70
identified clans in the GBR; 16 of which reside in the Burdekin (DAE, 2017). Coastal communitiesⒸ ISERD

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with high fish intake risk methyl-Hg and Cd (neurotoxins) exposure; illustrating community
dependence upon ecosystem health (Haswell-Elkins et al., 2006; Russell et al., 2015).
Table 1 Summary of mean cadmium, mercury and lead concentrations (mg/kg) incontaminated soils, fertilizers, sugar cane soil, and sugarcane by-products
loading to soil
Description
Fertilizer Derailment
Contaminated soil (n=7)
Contaminated soil (max)Fertilizer type (N-K-P)
0-9-0, (n=4)
TSP, 0-21-0
DAP, 18-20-0 (n=3)
13-14-12 plus
Sugarcane soil (± SD)
Sugarcane by-product
Filter Mud
Mill Ash
Biosolids
Soil loading limits

Cd (mg/kg)

Hg (mg/kg)

Pb (mg/kg)

4.21
45

n.a.
n.a.

53.7
790

0.5
0.5
0.5
0.5
0.069
Hg (kg/ha)
n.a.
n.a.
n.a.
n.a.

5.43
6.68
0.33
132
27
Pb (kg/ha)
n.a.
n.a.
n.a.
260

22
6.67
1.18
0.85
0.05
Cd (kg/ha)
0.011
0.003
0.11
2

Reference
Noller, 2021
Noller, 2021
Lottermoser, 2009
Lottermoser, 2009
Lottermoser, 2009
Lottermoser, 2009
Rayment, 2007; 2011
Rayment, 2011
Rayment, 2011
Rayment, 2011
NWQMS, 2000

Note: N-K-P nitrogen, potassium, and phosphorus; SP, superphosphate; TSP, triple superphosphate; DAP, Diammonium phosphate; sugarcane by-products load to soil (0-10 cm depth).

OBJECTIVE
This study investigates utilizing analytical indicators (Pb isotopes: 207/206Pb and 208/206Pb and heavy
metals: Cd, Pb, and Hg) to monitor sustainable agricultural practice and identify impacts offertilizer to Burdekin waterways. Alternative pollutant sources are also investigated. In this study,
appropriate fertilizer use and irrigation run-off control defines sustainable agricultural practice.
METHODOLOGYThe Burdekin catchment (area ~130,400 km2) resides in the seasonally dry tropics of NE QLD (Fig.
1). The Upper Burdekin is bordered by coastal ranges (750-1070 m height) < 50 km from thecoastline and feeds into the largest dammed catchment in QLD, Lake Dalrymple, impounded by the
Burdekin Falls Dam (BFD). In the dry-season, lower catchment flow is driven by allocated releases
from the BFD (mean ( ) minimum flow volume ± standard error (se): 4715 406 ML/month) anduncontrolled irrigation run-off (QLD Government, 2017). Approximately 75% of surface water
diversion schemes go to irrigation of sugarcane agriculture (Lewis et al., 2021). Monsoonal rains
govern flow volumes during the wet season ( se: 1535476 ML 255826). Extreme flooding
events occur annually, resulting in overspill at BFD, dislodging fertilized material, and dispersing
heavy metals to waterways. Monitoring of Burdekin River environment health is carried out during
the dry season (May-November se:101672 ML 36104) when vehicle access is possible, andsamples are safe to collect. Wet season volumes also cause dilution ( :15 times, 1986-2021) often
resulting in undetectable heavy metal concentrations (WMIP, 2022). As a consequence, heavy
metal concentrations from the run-off events are likely to pose greatest environmental risk during
the dry-season, when perennial river volumes have returned to “steady-state” flows. Embankment
soils/sediments (n=15, 0-100 mm depth, 2016, 2019) and water (n=35, unfiltered, 2016, 2018,2019 and 2020) were sampled in the Upper and Lower (estuary) sub-catchments of the Burdekinwatershed during the dry season. Water and sediment samples in 2016 and 2018 (Fig. 1) werecollected in June and July to demonstrate dry-season sources of heavy metals, and input of soil
seepage, representing concentrations coinciding with fall of the hydrographic curve. Samples in
x

x

x

x

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2019 and 2020 were collected in late November and early December (increase in hydrographic
curve). Thus, sample collections in 2019 and 2020 (Fig. 1) captured first flush and post run-off
heavy metal concentrations from the start of the wet-season, including any input from agricultural
fertilizers.

Fig. 1 Study area and sample site location map
Water and soil/sediment were analyzed at the NATA accredited laboratory (ISO/IEC 17025,
2017) Inorganic Chemistry, Queensland Health and Forensic Scientific Services, Coopers Plains,
QLD 4108, Australia. Agilent 8800 triple quadrupole inductively coupled plasma mass
spectrometer (ICP-QQQ; Agilent Technologies, Santa Clara, CA, USA) measured heavy metal
concentrations. Internal standards, spikes and certified reference materials (CRM, TM-28) wereused for quality assurance and quality control (QA/QC). QC for Hg analysis used 5% Hg (v/v)
HNO3 solution (SRM ID 3133, SRM Lot # 060204; High Purity Standards, Charleston, SC 29423,
USA). Pb isotope ratios (207/206Pb and 208/206Pb) in water, soil and sediment digests were determinedby Agilent 8800 ICP-QQQ (CRMs: GXR-1, JG-2, JR-1, JSD-1, JSD-2). Soil/sediment (includingCRMs) were prepared following the standard operating procedure (SOP 18191). Water samples
were analyzed directly after addition of 0.2 mL High Purity HNO3 to total 10mL. Pb isotope stock
standard solution was used from Choice Analytical and prepared via serial dilution. Ratios were
calculated using instrument software. Blank corrections were made with 0.5mL High Purity HNO3
in 10mL of deionized water. The ICP-QQQ is tuned following manufactures recommendations(Ref 11.3) and QIS: 30638 Operational Guidelines – ICP-MS. Total Hg measurements in soil wereanalyzed by National Measurement Institute Department of Industry, Innovation and Science,
Sydney, Australia.
RESULTS AND DISCUSSION
Mean se of total (T) Hg (0.016 ±0.002 μg/L) and TPb (0.15 ±0.02 μg/L) in freshwater remain
below ANZG (2018) default guideline values (DGVs) (Table 2). Mercury ( se: 0.011 ± 0.001) inthe estuary are below marine DGVs. In one estuary sample, TPb (4.99 μg/L) is above a marine
DGV of 4.4 μg/L (Table 2). At < 2 mm size fraction, embankment soil/sediment samples reflectse of TCd (0.11 0.10 mg/kg), THg (0.03 0.004 mg/kg) and TPb (11.02 1.65 mg/kg), allxxⒸ ISERD

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below soil and sediment DGVs throughout the upper and lower catchments (Table 3). The majority
of Burdekin soils/sediments (80%) and water (72%) samples, reflect isotopic compositions of canesoil (fertilizer enriched) and natural forest soils (Lottermoser, 2009; Fig. 2A and B). Isotope tracing
also suggests TPb Burdekin soils/sediments and waters are reflective of residual coal fly ash andambient-background dust (Turull et al., 2018). NSW coal fly ash signatures (Fig. 2; Diaz-somoana
et al., 2009) identified in Burdekin samples likely reflect historic contributions from a nearby
powerplant. A nearby coal-electricity generation station is the Collinsville Power Plant (Fig. 1).
Based on current flow statistics, the Burdekin River is highly variable, considerably influencing
annual sediment and nutrient loads (Brodie and Bainbridge, 2008). This is apparent in Pb isotope
compositions that vary with sample years (Fig. 2B). In 2016, isotope ratios trend toward phosphatefertilizers and are very similar to ratios found in fertilizer-enriched cultivation areas of the Tully
catchment (QLD; Turull et al., 2018). In 2018 and 2019, ratios in fresh and estuarian waters reflecta mixture of sources: NSW coal fly ash, dust, natural forest soils and leaded petrol (1996) (Fig. 2
B).
Table 2 Total Hg and Pb (μg/L) in the Burdekin River from 2016, 2018, 2019, and 2020.
Freshwater
N
Mean
SD
SE
Min
Median80 percentile
95 percentile
99 percentile
Max
Toxicant DGV

THg (μg/L)
24
0.016
0.01
0.002
0.005
0.013
0.022
0.027
0.044
0.048
0.06a

TPb (μg/L)
24
0.146
0.079
0.018
0.053
0.111
0.149
0.204
0.372
0.414
3.4b

THg* (μg/L)
11
0.011
0.004
0.001
0.004
0.011
0.011
0.015
0.018
0.019
0.1a

Saltwater
N
Mean
SD
SEM
Min
Median80 percentile
95 percentile
99 percentile
Max
Toxicant DGV

TPb (μg/L)
1
4.99
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
n.a.
4.4b

Note: N, count; SD, standard deviation; SE, standard error, *Collected in 2019 and 2020 n=11,
a 99% level of protection for Hg. b 95 % level of protection of species for Pb (ANZG-water, 2018)

Table 3 Total Cd, Hg and Pb (mg/kg), <2mm size fraction soil/sedimentfrom 2016 and 2019
Summaryn
No < values
Mean
SD
SE
Min
Median80 percentile
95 percentile
99 percentile
Max
Toxicant DGV*

TCd (mg/kg)
14
4
0.11
0.37
0.10
0.00
0.02
0.04
0.53
1.23
1.40
1.5

THg (mg/kg)
15
9
0.03
0.01
0.004
0.02
0.03
0.04
0.05
0.05
0.05
0.15

TPb (mg/kg)
14
0
11.02
6.16
1.65
2.40
9.13
16.00
21.10
24.22
25.00
50

Note: * No defined level of protection available (ANZG-sediment, 2018)

BFD stores are replenished during the wet-season from moonsoonal rains (cf. Townsvillerainwater se: pH 6 0.1; Na 1  4 mg/L, Cl 17 7 mg/L, from seawater) and released in the dry
season for irrigation (Crosbie et al., 2012). Site 7-19 samples, taken below BFD, captures wetseason water stores from dam releases. This is evident in 7-19 water characteristics, where pH andelectrical conductivity (EC) are influenced by wet-season rains ( se pH 7.4 0.01, EC: 193 1.1
µS/cm). Upstream (dry season) waters ( se pH 8.5 0.02, EC: 558 21.1 µS/cm) have higherxxxⒸ ISERD

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alkalinity/hardness and EC demonstrating differences between wet/dry waters. In the dry season,
heavy metal re-mobilization from sugarcane areas has low environmental, economic and social
risk; with one sample, TPb of 4.99 μg/L (2019), above DGVs of 4.4 μg/L (Table 2). Isotope tracing
reveals that fertilizer signals remain low throughout the catchment, suggesting sustainble irrigtion
practice and run-off control. The impact of fertilizer use in this study is likely minimized due to adelayed start to the wet season in 2019 and 2020 resulting in reduced rainfall run-off events. It is
recommended that on-land investigations should be carried out to further inform on fertilizer rates.

A

B

Fig. 2 Pb isotope ratios, 207Pb/206Pb and 208Pb/206Pb, suggest natural andanthropogenic sources (A) soil/sediment (2016 and 2019) and(B) water (2016, 2018 and 2019)
CONCLUSION
This study informed on baseline heavy metal concentrations and provides new insights ofalternative anthropogenic sources impacting Burdekin River water quality (i.e. Collinsville Power
Plant). Pb isotope tracing and elevated trace elements is effective at monitoring irrigation control.
Fertilizer use has no impact on the Burdekin River in the dry season, suggesting low environmental,
economic and social risk. Future land-based investigations could further inform on fertilization
rates and impact.
ACKNOWLEDGEMENTS
I acknowledge the University of Queensland, QHFSS and the Inorganic Chemistry team forproviding facilities, funding and access to their laboratory. A special thank you to my supervisors
Barry Noller and Tatiana Komarova for their support and mentorship.
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ACTFR. Report No. 08/05. Prepared for the Burdekin Dry Tropics NRM Water Quality Improvement Plan,
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Alengebawy, A., Abdelkhalek, T.S., Qureshi, R.S. and Wang, M. 2000. Heavy metals and pesticides toxicity
in agricultural soils and plants: Ecological risks and human health implications. Toxics, 9, 42, Retrieved
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Australian and New Zealand Guidelines (ANZG). 2018. Water quality management framework (water andsediment). Australian and New Zealand Guidelines for Fresh and Marine Water Quality, AustralianGovernment, Canberra, Australia, Retrieved from https://www.waterquality.gov.au/anz-guidelines/
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Brodie, J. and Bainbridge, Z. 2008. Water quality targets for the burdekin water quality improvement plan.
Coggan, A., Thorburn, P., Fielke, S., Hay, R. and Smart, C.R.J. 2021. Motivators and barriers to adoption of
improved land management practices, A focus on practice change for water quality improvement inGreat BarrierReef catchments. Marine Pollution Bulletin, 170, 112628, Retrieved from https://reader.
elsevier.com/reader/sd/pii/S0025326X21006627?token=E2AC38200C860E6F4118D84761122EDFD28
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Crosbie, R., Morrow, D., Cresswell, R., Leaney, F., Lamontagne, S. and Lefournour, M. 2012. New insights
to the chemical and isotopic composition of rainfall across Australia. Retrieved from https://www.
chemtrailsgeelong.com/uploads/3/4/7/1/34719470/new_insights_to_the_chemical_and_isotopic_composi
tion_of_rainfall_across_australia.pdf
Davis, A., Lewis, S., Bainbrdige, Z., Brodie, J. and Shannaon, E. 2008. Pesticide residues in waterways ofthe lower Burdekin Region: Challenges in ecotoxicological interpretation of monitoring data.
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Deloitte Access Economics (DAE). 2017. At what price? The economic, social and icon value of the Great
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deloitte.com/content/dam/Deloitte/au/Documents/Economics/deloitte-au-economics-great-barrier-reef230617.pdf
Diaz-somoano, M., Kylander, E.M., Lopez-Anton, A.M., Suarez-Ruiz, I., Martinez-Tarazona, R.M., Ferrat,
M., Kober, B. and Weiss, J.D. 2009. Stable lead isotppe compositions in selected coals from around theworld and implications for present day aerosol source tracing. Environmental Science and Technolology,
43, 1078-1085, Retrieved from https://pubs.acs.org/doi/pdf/10.1021/es801818r
Haswell-Elkins, M., Imray, P., Satarug, S., Moore, R.M. and O’Dea, K. 2007. Urinary excretion of cadmium
among Torres Strait Islanders (Australia) at risk of elevated dietary exposure through traditional foods.
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Lewis, E.S., Bartley, R., Wilkinson, N.S., Bainbridge, T.Z., Henderson, E.A., James, S.C, Irvine, A.S. andBrodie, E.J. 2021. Land use change in the river basins of the Great Barrier Reef, 1860 to 2019: A
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Queensland Government. 2017. Burdekin Haughton water supply scheme operations manual. Retrieved fromhttps://www.sunwater.com.au/wp-content/uploads/Home/Schemes/Burdekin-Haughton/BurdekinHaughton-WSS-Operations-Manual_May_2017.pdf
Rayment, E.G. 2007. Northeast Australian experience in minimizing environmental harm from waste
recycling and potential pollutants of soil and water. Communications in Soil Science and Plant Analysis,
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Russell, S., Sullivan, A.C. and Reichelt-Brushett, J.M. 2015. Aboriginal consumption of estuarine foodresources and potential implications for health through trace metal exposure; A study in Gumbaynggirr
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Research article
erdEnhancement of Carbon Fiber Electrode Performance using
Lactic Acid Bacteria and Steelmaking Slag
NARONG TOUCH*
Faculty of Regional Environment Science, Tokyo University of Agriculture, Japan
Email: nt207118@nodai.ac.jp

TADASHI HIBINO
Graduate School of Advanced Science and Engineering, Hiroshima University, Japan
Received 14 January 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract Microbial fuel cell technology (MFCT) provides many benefits to rural regions,such as organic waste disposal and renewable energy recovery. However, its performance is
low and must be improved for practical uses. Mixing steelmaking slag (SS) and lactic acidbacteria (LAB) with sediment can enhance the MFCT performance owing to LAB and iron
ions dissolved from SS attaching to the electrode surface. This study proposes a simple
method for attaching LAB and iron ions on carbon fiber electrode and subsequently
evaluating its performance. A carbon fiber electrode was placed in a bottle containing tap
water, SS, LAB, and bamboo powder (as nutrients for bacteria) for 7 days to allow LAB
and iron ions to adhere to its surface. The electrode was then used as the cathode of MFCT.
Results showed a decrease in the electrode potential and a consequent reduction in MFCT
performance owing to the attached LAB and iron ions. The performance improved after theelectrode was oxidized, suggesting that aeration is required during attachment to prevent thedecrease in electrode potential. After 1 month of electricity generation, the electrode withthe attachment produced high electrical current and exhibited low decrease in MFCT
performance owing to electricity generation. Therefore, attaching LAB and iron ions on theelectrode surface can improve the electrode performance and prevent performancedegradation owing to electricity generation.
Keywords microbial fuel cell, performance, electrode potential, attachment,
steelmaking slag, lactic acid bacteria

INTRODUCTION
Microbial fuel cell technology (MFCT) offers many benefits for rural regions, particularly indeveloping countries. For example, this method can be used to treat agricultural wastewater,household sewage, and organic waste, provide electricity to households, and recycle resources tofarmlands (Touch et al., 2020). However, the performance of MFCT remains low and must be
improved for practical uses. MFCT efficiency depends on the cathode and anode. A low electrode
performance will restrain the overall performance of MFCT. According to Yamasaki et al. (2018),
various types of potential losses occur during electron flow to an electrode. One of which isactivation loss that strongly influences electrode performance. Activation loss should be minimized
via pretreating the electrode to obtain a high MFCT performance. Furthermore, this loss increases
during electricity generation owing to the crystallization of ions present in water on the electrodesurface. Thus, a method for minimizing the performance reduction owing to electricity generationis necessary.
Adsorption of bacteria or metal ions on the electrode surface is a method for improving theelectrode performance. Wang et al. (2009) successfully enhanced electrode performance by
activating the bacteria at the electrode and consequently reducing potential losses. The boosted
electrode performance through bacterial attachment and biofilm formation has been widely studied
using the cyclic voltammetry measurement (Carmona-Martinez et al., 2011; Kang et al., 2012).
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Electrode performance can also be improved via coating a catalyst on the electrode surface.
Many types of catalyst have been used in chemical reactions, such as iron ions. Nishimura, et al.
(2018) reported that ferric ions dissolved from steelmaking slag (SS) improve sediment microbial
fuel cell (SMFC) performance. Using SS and lactic acid bacteria (LAB) in the anode of SMFC canalso enhance its performance (Touch et al., 2020). On this basis, the attachment of iron ions and
LAB on the electrode surface can increase the electrode performance.
OBJECTIVE
This study proposed a simple method for attaching LAB and iron ions dissolved from SS on carbon
fiber electrode. Changes in electrode potential and electricity generation (electrode performance)
owing to the attachment were subsequently investigated via measuring the polarization (currentvoltage relation) of electrode to determine changes in potential loss and examining the current todetect alterations in MFCT performance when the electrode is used as the cathode. The effects of
the attachment on MFCT performance reduction owing to electricity generation were also
discussed.
METHODOLOGY
Experimental Materials and Procedures
Dip-coating and electrodeposition are used to attach metal oxides on an electrode surface. For
practicality, a simple attachment process should be considered. Iron ions dissolved from SS are
adsorbed on the cathode of MFCT during long-term electricity generation (more than 6 months).
This study focuses on how to attach iron ions dissolved from SS to a carbon fiber electrode in ashort span (1 week).
Cylindrical bottles (120-mm inner diameter and 150-mm height) were filled with 500-mL tap
water. Some bottles contained 20-mm depth of SS and 20-mL lactic fermenting beverage, as shownin Fig. 1. Bamboo powder (5 g) was then added to the bottles and reduced the solution pH becauseof its fermentation. This process facilitates the dissolution of iron from SS. Furthermore, nutrientsfrom bamboo powder can activate LAB. Therefore, iron ions and LAB can attach to the electrodesurface in a short span.

Fig. 1 Experimental devices and materials
The electrode material was carbon cloth (News Company, PL200-E), preheated at 500°C for 1
h to improve its performance (Nagatsu, et al. 2014). The heated carbon cloth with a 100-mm widthand length was separated into fibers to form a brush-type electrode (photo in Fig. 1), which wasthen placed in the bottle for 7 days during bamboo powder fermentation.

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Operations and Measurements
Experiments were conducted following the procedures in Fig. 2. The electrodes were placed in thesolution for 7 days and then extracted from the bottle to measure their polarization using the circuitin Fig. 2a. In particular, the anode potential was fixed at −0.64 V to display a clear variation of thecathode (the electrode taken from the bottle) performance. An external resistance with 2.2 Ω–10kΩ was loaded between the anode and cathode. Cell voltage was recorded 1 min after loading eachexternal resistance and used to calculate the current according to the Ohm’s law: I = U/Rex, where
U [V] is the voltage, I [A] is the current, and Rex [Ω] is the external resistance. Power P was
calculated according to P = IU. Current and power densities were obtained by dividing these values
by the surface area of the electrode, i.e., 0.01 m2.
After polarization measurements, the electrodes were placed in the bottle filled with tap water
near the water surface for 7 days to examine the effects of oxidation on the electrode performance.
The polarization of each electrode was remeasured after oxidation. The electrode was used as thecathode of SMFC (Fig. 2b) for 1-month electricity generation to examine its long-term
performance. For electrical current generation, an external resistance of 2.2 Ω was loaded between
the anode and cathode. Although different SMFCs were used for each case, the initial anode
potential of each SMFC was the same order of magnitude.
CathodeExternal resistance

20 mL of lactic
fermenting beverage
5 g of bamboo powder

Tap water (500 mL)

Tap water (1 L)
R

Anode

V
Potentiostat
For a fixed
potential of -0.64 V(a) Polarization measurements
120 mmElectrode oxidation (7 days)

Tap water
2.2 ΩVPolarization measurements

Paddy soil

50 mm

➢ Polarization measurements

100 mm7 days<Anode >Steelmaking slag
(100*100) mm2 –brush type(b) Current generation (30 days)

Fig. 2 Operations and measurement methods
After electricity generation, polarization and exchange current density were measured to
examine the effects of electricity generation on the electrode performance. Exchange current
density is an index for evaluating activation losses at the electrode surface, that is, a high exchange
current indicates a small potential loss, i.e., a high electrode performance. Exchange current density
was determined using the method noted in the study by Nagatsu et al. (2014).
RESULTS AND DISCUSSIONⒸ ISERD

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Effects of LAB and Iron Ion Attachment on the Electrode Performance

0.4

Electrode potential (V vs. Ag/AgCl)

Electrode potential (V vs. Ag/AgCl)

After fermentation and when each electrode was place in tap water, the electrode potential wasmeasured to examine the effects of LAB and iron ion attachment on the electrode performance.
Comparison of electrode potential is shown in Fig. 3. The electrode potential largely decreased
from 0.36 V (Case 1) to 0.01 V (Case 2) owing to LAB adsorption, to 0.06 V (Case 3) owing toiron ion adsorption, and to -0.11 V (Case 4) owing to LAB and iron ions adsorption (Fig. 3a). Afterthe electrode was oxidized for 7 days (Fig. 3b), the electrode potential (Cases 2-4) largely increased(from 0.20 V to 0.25V).
These results indicate that the proposed method can attach LAB and iron ions dissolved fromSS to the carbon fiber electrode. However, the attachment decreases the electrode potential.
Consequently, the MFCT performance is reduced when the electrode is used immediately after theattachment. Given that electrode oxidation increases its potential, oxidizing the electrode with theattachment should be conducted before its usage in MFCT. Aeration should be performed duringattachment to prevent the decrease in the electrode potential.

0.3
0.2
0.1
0

-0.1

0.4

0.35
0.3
0.25

0.2
0.15

0.1
0.05

-0.2

0
Case 1Case 2

Case 3

Case 1Case 4(a) after attachment

Case 2

Case 3

Case 4(b) after electrode oxidation

Fig. 3 Comparison of electrode potential at different conditions
Changes in Electrode Performance Owing to the Attachment of LAB and Iron Ions

50
45
40
35
30
25
20
15
10
5
0

Exchange current density (mA/m2)

Current density (mA/m2)

Fig. 4 compares of the electrode performance of each condition. The electrode without attachment(Case 1) produced only approximately 3 mA/m2 of current density. Meanwhile, the electrodeattached to either LAB (Case 2) or iron ions (Case 3) generated 30–35 mA/m2, a 10-fold increases(Fig. 4a). These results indicate the improved electrode performance can be attributed to theadsorption of LAB or iron ions on the electrode surface. A further increase in current density was
also observed when LAB and iron ions were attached to the electrode (Fig. 4a, Case 4). Therefore,
irons ions aid LAB to transfer electrons to electrode.

Case 1Case 2
Case 3
Case 4

0

5

10

15

20

25

90
80
70
60
50
40
30
20

10
0

30

Case 1

Operating time (day)(a) temporal change of current density

100

Case 2

Case 3

Case 4(b) exchange current density after current generation

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The exchange current density of each case was compared in Fig. 4b. As shown in Fig. 4b, theexchange current density increased after the attachment of either LAB or iron ions on the electrodesurface. This finding indicates that the potential loss at the electrode surface is reduced owing to
the attachment, i.e., electrons are easily transferred to electrode via LAB or iron ions. In addition,
the exchange current density of the electrode with iron ions attached (Case 3) was 80 mA/m 2 which
was two-fold higher than that of the electrode with attached LAB (Case 2, 40 mA/m2). Iron ion
attachment provides a better performance than LAB attachment. However, the combination of LAB
and iron ions exhibits a higher performance than the use of each component alone.
Reducing the Performance Decrease Owing to Electricity Generation by LAB and Iron ions

200
180
160
140
120
100
80
60
40
20
0

Case 1Case 2

Case 3

Case 4

Power density (mW/m2)

Power density (mW/m2)

Figures 5a and 5b depict the comparison of performance (current and power density relationship)for electrodes with and without electricity generation. Power density and current density decreased
owing to electricity generation. In the experiments, crystallized compounds were observed on theelectrode surface and can contribute to the decrease in performance.

0

100

200

300

400

500

200
180
160
140
120
100
80
60
40
20
0

Case 1

0

600

100

Case 2200

Case 3300

Case 4

400

500

600

Current density (mA/m2)

Current density (mA/m2)(a) without electricity generation(b) with electricity generation

Fig. 5 Comparison of performance for electrodes with and without electricity generation
An 80-mW/m2 reduction in power density was observed for the electrode without attachment(Case 1) and 70-mW/m2 reduction for the electrode with iron ion attachment (Case 3). Only 12mW/m2 reduction in power density was observed when LAB attached to the electrode surface withand without iron ions (Cases 2 and 4). Therefore, LAB attachment on electrode surface effectively
improves the reduced performance owing to electricity generation. Crystallization cannot occur on
the electrode surface with LAB.
CONCLUSIONS
Laboratory experiments were conducted to verify the efficiency of the proposed simple method for
attaching LAB and iron ions on a carbon fiber-electrode and to examine the effects of attachment
on the electrode performance. Approximately 300-mV reduction in electrode potential wasobserved owing to the attachment. Nevertheless, the electrode potential recovered almost to theinitial state after oxidizing the electrode by placing it in tap water near the water surface for 7 days.
Thus, aeration should be conducted during attachment to prevent the decrease in the electrodepotential. A 10-fold increase in current density was observed for the electrode attached with either
LAB or iron ions. A high increase in current density was obtained when LAB and iron ions wereattached to the electrode. On the basis of the increase in exchange current density owing to theattachment, the potential loss at the electrode surface is reduced owing to the attachment, i.e.,electrons are easily transferred to electrode via LAB or iron ions. Finally, the performance decrease
owing to electricity generation was largely (88%) reduced for the electrode attached to LAB.
Therefore, the attachment of LAB on the electrode surface can restrain the formation of crystallizedcompounds.
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ACKNOWLEDGMENTS
The authors gratefully acknowledge the partial funding from JSPS: Grant-in-Aid for Scientific
Research (B) (Grant Number: JP-21H01437). The authors would also like to thank the students of
the Rural Environmental Engineering Laboratory, Tokyo University of Agriculture, for their efforts
in collecting data.
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Kang, J., Kim, T., Tak, Y., Lee, J.H. and Yoon, J. 2012. Cyclic voltammetry for monitoring bacterial
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Nagatsu, Y., Tachiuchi, K., Touch, N. and Hibino, T. 2014. Factors for improving the performance of
sediment microbial fuel cell. Journal of Japan Society of Civil Engineers Ser B2 (Coastal Engineering),
70 (2), 1066-1070, Retrieved from DOI https://doi.org/10.2208/kaigan.70.I_1066 (in Japanese)
Nishimura, K., Yamaji, S., Touch, N. and Hibino, T. 2018. Usable output of sediment microbial fuel cellunder the use of steel slag mixed-sediment as a fuel. Journal of Japan Society of Civil Engineers Ser B2(Coastal Engineering), 74 (2), 1183-1188, Retrieved from DOI https://doi.org/10.2208/kaigan.74.I_1183(in Japanese)
Touch, N. and Nakamura, T. 2020. Methods for improving the performance of paddy soil-used sedimentmicrobial fuel cells. International Journal of Environmental and Rural Development, 11 (2), 1-6.
Wang, X., Feng, Y., Ren, N., Wang, H., Lee, H., Li, N. and Zhoa, Q. 2009. Accelerated start-up of twochambered microbial fuel cells: Effect of anodic positive poised potential. Electrochimica Acta, 54 (3),1109-1114, Retrieved from DOI https://doi.org/10.1016/j.electacta.2008.07.085
Yamasaki, R., Maeda, T. and Wood, K.T. 2018. Electron carriers increase electricity production in methane
microbial fuel cells that reverse methanogenesis. Biotechnology for Biofuels, 11, 211, Retrieved from
DOI https://doi.org/10.1186/s13068-018-1208-7Ⓒ ISERD

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Research article
erdCharacteristics of Ion Components of Clearwater Stream
Watershed in an Agricultural Area with Multivariate
Analysis
YURI YAMAZAKI*Tokyo University of Agriculture, Tokyo, Japan
Email: yy206792@nodai.ac.jp

TOSHIMI MUNEOKA
Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, Japan

CHIE MATSUDA
Zukosha Co., Ltd., Hokkaido, Japan

MASATO KIMURA
Obihiro University of Agriculture and Veterinary Medicine, Hokkaido, JapanOSAMU TSUJI
Zukosha Co., Ltd. / Obihiro University of Agriculture and Veterinary Medicine, Hokkaido,
Japan
Received 29 January 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract Restoring the clear-stream environment that once existed in agricultural areas is
one of the major challenges for the development of sustainable agriculture. Therefore, we
analyzed the ionic components of the Rekifune and Satsunai River basins, which are
regarded as clear-water basins in the Tokachi region of Hokkaido, using principal
component analysis and cluster analysis based on surveys conducted in June and September
2014. The results showed that most of the sampling points in the Rekifune and Satsunai
drainages were comparable to the average values of water quality assessed as clear-streams
in Japan. However, in the tributaries of the Rekifune River, since Cl- and Na+ increased
characteristically, the water quality was degraded by anthropogenic pollution sources suchas domestic wastewater. In the Satsunai River, the water quality of the downstream
tributaries was degraded due to agriculture. In addition, in one of the tributaries,
deterioration of water quality was observed only in September, and the water quality of themain river immediately after the inflow of this tributary was also affected. These results
indicate that the water quality in the two basins in the predominantly agricultural area isgenerally good. Still, it is necessary to identify the source of pollution in some areas andtake countermeasures.
Keywords river water quality, agricultural area, principal component analysis,cluster analysis

INTRODUCTION
Historically, rivers flowing through rural areas in Japan had clear water and were home to various
aquatic life. However, modern agricultural land-use changes and river alterations have resulted in
the disappearance of the 'clear water' environment in rural areas. This water pollution caused bymodern agriculture has become a global problem. We now understand the need to conserve intact
rivers in agricultural areas and restore altered river ecosystems to meet the global challenge ofmore sustainable agriculture.

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The term “clearwater stream” generally refers to uncontaminated rivers-however, no scientificdefinition in Japan. For example, the Japanese government publicizes river rankings based on water
quality measurements, particularly biochemical oxygen demand (BOD). Therefore, any riverranked highly in the river-ranking program is defined as a clearwater stream. Also, rivers selected
as “100 clearest streams in Japan” by the Ministry of the Environment are evaluated as clearwater
streams.
The Tokachi region of Japan, which has an essential role in Japan’s food supply, has twoclearwater streams: the Rekifune and Satsunai rivers. Both had been ranked high in thegovernment's river-ranking program in prior years, and both had low BOD values. In aquestionnaire provided to Hokkaido residents to rank clearwater streams, the Rekifune Riverranked second, and the Satsunai River ranked 5th place (Shimatani et al., 1996). Therefore, it isclear that both rivers are recognized as being clearwater streams in Hokkaido. However, ever sincelarge-scale agriculture commenced in the watershed of the Rekifune and Satsunai drainage basins,
water pollution caused by these agricultural activities has become a concern. In 2008, for example,
water quality studies of the Rekifune and Satsunai rivers had shown elevated nitrogenconcentrations in river water caused by agricultural runoff (Yamazaki et al., 2017).
OBJECTIVE
This study evaluated ion components of river water and all water quality factors using multivariate
analysis in clear stream watersheds at a large agricultural area to develop guidelines for preserving
river environments.
MATERIALS AND METHODOLOGY
Study Sites
This investigation examined two clearwater stream drainages in the Tokachi region in eastern
Hokkaido, Japan: the Rekifune and Satsunai drainages. Both rivers supply irrigation and tap water
to the residents in the Tokachi region. Also, the Rekifune and Satsunai watersheds are
geographically adjacent to one another in their headwaters. The catchment areas are similar, andthe primary land use of the region is agriculture and forest.
The primary land use in the Satsunai drainage is agricultural cropland (30% of total area),
including wheat, potato, sugar beet, and beans. Both chemical and organic fertilizers (livestock
manure) are applied to croplands. In the Rekifune drainage, pasture and forage crops are produced,
constituting 17% of the total land area.
Water Quality Investigation
We selected fourteen water quality sampling stations in the Rekifune drainage and 21 points in theSatsunai drainage; these stations were sampled once per month in June and September 2014 during
normal water levels; a total of 42 and 63 samples were collected from the Rekifune and Satsunai
River drainages respectively (Fig. 1). The sampling points were located on the main stems (Stations
A-F on the Rekifune River and Stations 1-11 on the Satsunai River) and downstream along
tributaries (Stations G–N on the Rekifune River and Stations 12-21 on Satsunai River).
Electrical conductivity and water temperature were measured using a digital conductivity
meter (DKK TOA Corporation; 592896; Japan). We analyzed the following ion components ineach sample: Cl−, NO3−, NO2−, SO42−, Na+, K+, Ca2+, and Mg2+ using liquid chromatography.
Multivariate AalysisⒸ ISERD

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Fig. 1 Land use and sampling stations of the Rekifune and Satsunai River drainages
We used the R package (R Foundation for Statistical Computing; Ver. 3.0.3; Austria) for cluster
and principal component analyses. The ion components (Cl−, NO3−, SO42−, Na+, K+, Ca2+, andMg2+) were used as input variables. Cluster analysis and principal component analysis are bothtypes of multivariate techniques. We applied Ward’s method to the cluster analysis. Principal
component analysis (PCA) was derived using the “princomp” algorithm of the R package.
RESULTS AND DISCUSSION
Cluster Aalysis and Pincipal Cmponent Aalysis of the Rver Water Qality
Cluster and principal component analysis using correlation matrix were carried out for sevenvariables: ion concentrations (Cl−, NO3−, SO42−, Na+, K+, Ca2+, and Mg2+) at 35 sampling stations in
the Rekifune and Satsunai drainages. We compared water quality between the mean ion
concentration of river water and groundwater from “100 clearest streams in Japan” of 1985 and2008 (Yabuzaki et al., 2009) as a reference. These analyses were performed for the July and
September observations in the Rekifune and Sastunai drainages, respectively.
Table 1 shows the cluster analysis results and PCA score of PC1 and PC2 of the July and theSeptember observations, respectively. First, the “100 clearest streams in Japan” of 1985 and 2008
were classified as Cluster1 and Cluster2, respectively, in the July observation data. Also, twentyeight sampling stations (11 stations of the Rekifune and 17 stations in the Satsunai) were classifiedⒸ ISERD

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into Cluster1 and Cluster2. Therefore, most of the main stems and the tributaries of the Rekifune
and the Satsunai drainages have the same level of water quality concentration as the “100 clearest
streams in Japan”. However, three tributaries of the Rekifune and four of Satsunai drainages,
classified as Cluster3 to Cluster5, show a different trend from the “100 clearest streams in Japan”.
Next, in the September observation data, the “100 clearest streams in Japan” of 1985 and 2008
were classified as Cluster1. Also, twenty-four sampling stations (11 stations of the Rekifune and 13
stations in the Satsunai) were classified into Cluster1. The results of the Rekifune River were likethose of the July cluster analysis, while the Satsunai River showed a different trend. Particularly,
Stations 5 and 14 in the Satsunai River were classified as Cluster5.
Table 1 Results of cluster analysis and PCA score

Fig. 2 shows the eigenvector of PC1 and PC2, also Fig. 3 shows the results of the principal
component analysis, color-coded into clusters 1 to 5 as described above. The x-axis is the firstprincipal component (PC1), and the y-axis is the second principal component (PC2).
The cumulative contribution of the principal component analysis was 95% and 82% from thefirst to the second principal components in July and September observations, respectively,
indicating that the characteristics of river water quality in the Rekifune and Satsunai Riverdrainages can be summarized by two principal components. The eigenvectors of the first andsecond principal components showed a similar trend in both July and September. First, theeigenvectors of PC1 were positive for all items. PC1 indicates the overall characteristics of theriver water quality, and the larger the positive value of PC1 is, the worse the river water quality is.
The eigenvectors of PC2 showed positive values for Cl−, Na+, and K+, and negative values for NO3−,
SO42−, Ca2+, and Mg2+. The negative values of PC2 indicate that the components are contained in
fertilizer, so it can be inferred that when PC2 is large with negative values, the influence ofagriculture is significant. On the other hand, for the item with a positive PC2, the increase in Cl−,and Na+ concentrations in river water due to the inflow of domestic wastewater was reported in thesuburbs of urban areas (Taniguchi et al., 2004; Hirata et al., 1999), which may reflect
anthropogenic influences other than agriculture.
Cluster1 and Cluster2 in July, and Cluster1 in September, show the range of -1.9 to 0.8 forPC1 and the content of -0.6 to 0.5 for PC2. The main stems and most of the tributaries of the
Rekifune and Satsunai Rivers are comparable to those of the “100 clearest streams in Japan”.
On the other hand, the three sites in the tributaries of the Satsunai River, classified as Cluster3
in July and Cluster2 in September, showed positively large values of PC1 and negative values of
PC2 in both July and September. The tributaries located in the lower reaches of the Satsunai RiverⒸ ISERD

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are affected by agriculture. Although the water quality is worse than “100 clearest streams inJapan”, it does not significantly affect the water quality of the main river of the Satsunai River.
In addition, Cluster4 in July and Cluster3 in September have a larger PC1 than the “100clearest streams in Japan”. Therefore, the water quality tends to deteriorate, although not as
markedly as the tributaries in the lower reaches of the Satsunai River.
One tributary station of the Rekifune River, classified as Cluster5 in July and Cluster4 in
September, showed large positive results for both PC1 and PC2. The water quality at station M of
the Rekifune River is degraded by anthropogenic influences other than agricultural influences in
the period of July to September at least.
Finally, one station in the main stem of the Satsunai River and one station in a tributaryclassified as Cluster 5 in September were both classified as Cluster 1 in July, and the river water
quality in July was good. However, in September, PC1 became larger with positive values, and thewater quality deteriorated. On the other hand, PC2 is positive, ranging from 0.8 to 1.4. Therefore,
although it is not as pronounced as station M in the Rekifune River, it is considered that the river isaffected by anthropogenic factors other than agriculture only in September. Since station 5 of themain stem of the Satsunai River is just after the inflow of the tributary of station14, it is consideredthat there is a pollution source around station 14, which deteriorates the river water quality of themain stem around station5.

Fig. 2 Eigenvector of PC1 and PC2

Fig. 3 Relationships between PC1 and PC2Ⓒ ISERD

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CONCLUSION
In this study, we investigated the water quality of the Rekifune and the Satsunai drainages, which
are in a large agricultural area and are regarded as clear streams. We compared them with the "100clearest streams in Japan" results using multivariate analysis. As a result, the water quality of bothrivers is comparable to that of the “100 clearest streams in Japan” and can be evaluated as a goodwater quality environment. However, the Rekifune River deteriorated at one station due toanthropogenic influences such as domestic wastewater. Furthermore, there is a concern about
pollution sources operating at different times in the Satsunai River. Although the effects of thesepollution sources have not had a significant impact on the main rivers of both the Rekifune and theSatsunai Rivers, it is necessary to identify these pollution sources and take measures to ensuresustainable conservation in the future.
ACKNOWLEDGEMENTS
This research was supported by JSPS KAKENHI, Grant Number 15J04743, 2015. We would liketo express my gratitude to the research assistance provided by the students, the Obihiro Universityof Agriculture and Veterinary Medicine.
REFERENCES
Hirata, T., Ii, H., Hasebe, M., Egusa, N., Sakamoto, Y., Kumekawa, T., Nishiyama, K., Sakai, N. and Iwasaki,
H. 1999. The effect of land use upon river water chemistry -The Ishi River basin in Osaka Prefecture-.
Journal of Japan Society of Civil Engineering, 1999 (614), 97-107, Retrieved from DOI https://doi.org/10.2208/jscej.1999.614_97
Shimatani, Y., Denda, M., Mashita, K. and Koike, T. 1996. The study on the image of clear streams, Howdoes people evaluate the rivers. Environmental System Research, 24, 20-25, Retrieved from DOI
https://doi.org/10.2208/proer1988.24.20
Taniguchi, M., Ii, H., Hirata, T. and Ishizuka, M. 2004. Changes of substances derived from domestic sewage
in Yamatogawa River Basin. Proceedings of Hydraulic Engineering, 48, 1465-1470, Retrieved from DOI
https://doi.org/10.2208/prohe.48.1465
Yabuzaki, S. and Shimano, A. 2009. Characteristics of water quality in the selected 100 spots of clearlypreserved water of the Heisei Era in Japan. Journal of Groundwater Hydrology, 51 (2), 127-139,
Retrieved from DOI https://doi.org/10.5917/jagh.51.127
Yamazaki, Y., Muneoka, T., Okazawa, H., Kimura, M. and Tsuji, O. 2017. Evaluation of river water quality
with multivariate analysis in clear stream watersheds in agricultural area. Journal of Water andEnvironment Technology, 15 (3), 86-95, Retrieved from DOI https://doi.org/10.2965/jwet.16-040Ⓒ ISERD

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Research article
erd

Evaluating Ion Exchange Capacity of Molten Slag for
Hydroponic System
ANTONIO PEREZ FUENTES
Graduate School of Agro-Environmental Science, Tokyo University of Agriculture, Tokyo, JapanSARVESH MASKEY
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan

HIROMU OKAZAWA*
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan
Email: h1okazaw@nodai.ac.jp

YURI YAMAZAKI
Faculty of Agriculture, Tottori University, Tottori, JapanTOMONORI FUJIKAWA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanTOSHIMITSU ASAI
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan
Received 1 February 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract Hydroponic farming promotes high-efficiency water, fertilizers, and highproductivity under a controlled environment. However, the use of this system needs
consistent application of fertilizers, increasing the cost of operations. Molten Slag (MS), a
waste from the Municipal Solid Waste Incineration has essential nutrients that can be usedas fertilizer. The objective of this study was to clarify the releasing process of nutrients bymolten slag to be applied as a substrate in hydroponic system. For this, anion and cation
contents of three varieties of Molten Slag (MS1, MS2, MS3) were determined in thelaboratory by a shaking method. The nutrient content, P2O5, K2O, MgO and CaO were in
MS1, MS3 and MS2. The quantification ion released was performed at 1, 6, 12 and 24
hours. It was observed that MS3 had performed the best condition in the releasing processof K+, Mg+, SO42- and Cl-. Although MS1 had higher nutrient content, MS3 released higher
contents of those minerals among the samples. According to the result of this study, it was
confirmed that MS3 has a high potential for hydroponic farming.
Keywords molten slag, hydroponic system, ion exchange capacity, releasing nutrientsINTRODUCTION
Around 200 billion tons of fertilizers are produced annually for agricultural purposes (FAOSTAT,
2021). The use of these fertilizers and water supply tends to increase to provide food safety for 9
million people toward 2050. The benefit of fertilizers in agricultural production is remarkable since
it improves yields and keeps fertile soil. On the other hand, the constant use of fertilizers not only
increase the costs but hazard the ecological balance with releasing of greenhouse gases andeutrophication to water bodies (Sedlacek et al., 2020).
Molten Slag (MS) is a by-product of the Municipal Solid Waste Incineration -MSWI- process(Fig. 1). The process to generate molten slag starts with the addition of wastes inside a furnace, thiswaste can be paper, plastic, glass, steel, aluminum, food waste/raw garbage, waste oil, among
others. After burning most of the organic wastes, the residues are separated as ferrous materials(aluminum, steel, incombustibles), vitreous material and molten slag. The gas generated in thoseⒸ ISERD

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furnaces goes through a chamber for purification and generation of energy, and the fly ash is alsocollected for future processing. The composition of molten slag varies according to the diverse
wastes in every municipality and the type of furnace in which they are processed (Czop andŁaz´niewska-Piekarczyk, 2020). Molten slag shares similarities to the slag generated by the ironand steelmaking process, and they have been tested for correct use as a cement aggregate, roadbuilding and for soil correction (Dubey et al., 2019; Zeng et al., 2020; Devnita et al., 2021). Altland,
et al. (2015) described the possibility of up taking micro-nutrients from these types of slag and thespontaneous vegetation in landfills where molten slag is storage (Gomes et al., 2016) opens to
discussion if the contents of Ca, K, Mg, and Na, from molten slag can be a good source of nutrientsfor plants. Molten slag collected from MSWI has not been used in agriculture and recent studies(Kobayashi et al., 2004; Sekito et al., 2014) found that there was not leaching of heavy metals inseveral samples analyzed. As the generation of wastes increases around the world, this study
reveals the possibility to release beneficial ions to assess the growth of crops with this material.

Fig. 1 Municipal solid waste incineration process
OBJECTIVE
The objective of this study was to quantify and record the releasing process of nutrients released
and retained by three types of molten slag from the Kanto region in Japan and estimate theavailability of those nutrients for crop production under hydroponic conditions.
METHODOLOGY
We collected three types of molten slag from Kofu (MS1), Kamiina (MS2) and Nishi-Akikawa(MS3), the dried content of CaO, MgO, K2O and P2O5 was determined in principle, then theanalysis of releasing those minerals was carried out. First, we prepared 10 g of every sample inside
a bottle with 50 mL of Ultra-Pure Water and two replicates. The samples were shaken at 180 rpm
for 1, 6, 12 and 24 hours. Electrical conductivity (EC), pH and anion/cation contents were
measured. Anion and cation contents in the water samples, which were filtered by membrane filter
with a diameter of 0.45 μm, were measured by a spectrometric method using Ion analyzer (IA-300,
HORIBA). Only seven ions were involved in the discussion, considering plant growth, and theconcentration is given in mg/L. ANOVA and T-test were applied to find any significant difference
among the samples.

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RESULTS AND DISCUSSION
Chemical Properties of Molten Slag
MS1

28

24

Concentration (mg/L)

Concentration (mg/L)

20

20

16

16

12

12

20

16

12

8

8

8

4

4

4

0

0

0
1

6

Na+
Na+

12

1

24

Elapsed time (h)
K+
Mg+
K+
Mg+

MS3

28

24

24

Concentration (mg/L)

MS2

28

6

Na+
Na+

Ca+
Ca+

12

Elapsed time (h)
K+
Mg+
K+
Mg+

1

24

Ca+
Ca+

6

Na+
Na+

12

Elapsed time (h)
K+
Mg+
K+
Mg+

24

Ca+
Ca+

Fig. 2 Amount of cation released by every type of slag
along 1, 6, 12 and 24 hours of shaking treatment
Table 1 Chemical properties of three varieties of molten slag
Per Wind Dried Material
pH
Units

EC

CEC

Per Dried Material
NH4-N

Inorg. N

3

Bulk density

P2 O 5

K2O

MgO

CaO

Zn

Cu

Fe

mS/cm

meq/100g

kg/m

mg/100g

mg/100g

mg/100g

mg/100g

mg/100g

mg/100g

mg/kg

mg/kg

mg/kg

MS1

7.17

0.04

ND

1.58

0.6

0.6

21

2.6

8.6

142

48

208

34.7

MS2

7.78

0.04

ND

1.59

0.9

0.9

12

1.6

6.2

42

34

106

12.9

MS3

7.84

0.06

0.1

1.51

0.6

0.6

7

2.2

5.3

103

102

182

40.7

Obtained by dry method in Katakura Co Op Agri LabsND: Not Detected

MS1 has higher content of P2O5, K2O, MgO, CaO, and Cu as shown in Table 1. On the other hand,MS2 has the lowest nutrient content in all aspects, except for P2O5 and MgO, including the highest
density.
Releasing of Cations by Molten Slag
During the test, pH values did not raise levels higher than nine, but this value is still consideredhigh for crop development. It was expected that MS1 would have the largest EC due to thesignificant amounts of CaO, MgO and K2O, however, after 24 hours none of those ions tend toincrease in this material. The leachate of calcium explains the peak values observed at 6 hours ofshaking into the water, producing carbonation's reaction (Huntzinger et al., 2009).
K+ plays a significant role in many synthetic, physiological and biochemical processes inplants. This element is present in the soil in low concentrations, from 0.2% to 3.3% of the total soil
mass (Barker and Pilbeam 2015). Although a low value of K+ was found in this releasing process ofmolten slag, the concentrations in the dried material are acceptable. The range goes from 0.0011 to
0.0028 mg/g in MS2 and from 0.0037 to 0.0057 mg/g in MS3. At least 16%, 21% and 31% werereleased from the MS1, MS2 and MS3, respectively. MS3 is the most suitable supplying more K +into the water.
Even though MS1 has more significant amounts of MgO than MS3, it was observed that thepercentage of Mg+ released by MS1 is lower compared to MS3, producing almost the double
amount of Mg+ released in the same period. In comparison, MS2 has around 0.062 mg/g andreleased 0.0068 mg/g. It is only about 10% of MgO.
For the efficient process to obtain better gas in the incineration process, calcium oxide is added
to clean the impurities (Zheng et al., 2018), this component remains in the slag and becomes themost abundant next to the silicates. MS1 was the material with the highest content in manyⒸ ISERD

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compounds, having values of Ca2+ superior to 1.4 mg/g; moreover, after 24 hours in the shaking
process, it was determined that the values of the Ca2+ released are still low compared to 26%
released from the MS2. Calcium is not an essential nutrient for plants, but it is a requirement. An
excessive amount of Ca2+ can result in plants toxicity. Plants can allocate around 100 mg/g per dry
matter (Römheld, 2012; White and Brown, 2010). When the delivery of Ca2+ to the soil exceeds theplant’s uptake capacity, there is a risk of accumulation of Ca2+ at the surface of the roots and mostof the time to the precipitation as CaCO3, CaSO4, or Ca oxalate in rhizocylinders around the roots
induced by P deficiency (Newman and Römheld, 1998; Marschner and Rengel, 2012). Ca2+
released by MS3 ranges between 7.5 and 13%, meanwhile in MS1 and MS2, it goes from 4.6 to
7.7% and from 13.5 until 26%, respectively.
The primary function of Na+ seems to be to maintain osmolality in the plant tissues of the
halophyte seepweed under NaCl conditions (Mori et al., 2010). However, Na+ is not considered anutrient for most plant species. Subbarao et al. (1999) showed that it could be a substitute forpotassium in Beta sp. to a large extent and, it has been accepted as a micronutrient in some C4
plants that require Na+ for cotransport. Although Na+ values were not obtained in the dried content
analysis of the samples, it was observed that there was a leaching of sodium along with the shaking
test, there was not a variation among the shaking period, but there is a significant difference among
the three samples. Assuming that the contents of sodium in MS2 are also lower than the following
two samples as occur for the minerals, this is the reason why this sample had the lowest trend, as
observed in Fig. 2. High Na/Ca ratios may lead to a deficiency of Ca2+ in Sodic or saline soils dueto the excess of Na+ in the soils (White, 2015) that’s why it is important to consider that ratios of
Na/Ca are also balanced. The ratio of Na/Ca of Molten slag goes from 0.03 to 0.05 in all thesamples with contents from 0.020 mg/g in MS1, 0.011 mg/g in MS2 and 0.022 mg/g in MS3.
MS1

10

8

4

Concentration (mg/L)

Concentration (mg/L)

6

6

4

2

2

1

6

12

24

Elapsed time (h)ClCl-

PO4PO43-

6

4

2

0

0

MS3

10

8

8

Concentration (mg/L)

MS2

10

0
1

6

12

24

1

6

SO4SO42-

ClCl-

PO4PO43-

SO4SO42-12

24

Elapsed time (h)Elapsed time (h)ClCl-

PO43PO4-

SO4SO42-

Fig. 3 Anion released by every type of slag along 1, 6, 12 and 24 hours
Anion Concentration
From the three samples analyzed in this study, only MS2 showed a small fraction of PO42- released;
it is possible to say that 0.3 mg of PO42- are available in the water to be taken by the plants fromthis material. The range of PO42- in MS2 goes from 0.0008 mg/g to 0.0018 and finally to 0.0012 mg
along the treatment. Only MS2 could perform this condition from the three samples since MS1 andMS3 didn’t show great changes during the same period.
SO42- is an important nutrient that acts as a major structural component of proteins, also
participates in several processes like photosynthesis, N2 fixation, chlorophyll production, andcatalytic activities of many enzymes (Mills and Jones, 1996; Hawkesford, 2010). An unbalanced
application of N fertilizers with low or lack of sulfur can indicate the plant’s sulfur deficiency. In
principle, the samples of molten slag released around 0.013 mg/g of SO42- at the first hour, but after
24 hours, it was only MS3 which increased to 0.019 mg/g. Since the molten slag can’t provide
nitrogen such as NH4+ or NO3-, the sufficiency of sulfates in agricultural systems will be directly
related to the content from an external nitrogen source. Although molten slag can provide few SO42to crops systems, this quantity is not enough to accomplish the plant requirements.
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Cl- concentrations up to 500 mg/L have been supplied in sweet onion and demonstrated thatthe requirement of chlorides is only exceeded by N, P and K (Randle, 2005). Furthermore, theconcentration observed in the releasing process from the three types of molten slag doesn’t exceed
more than 3 mg/L by 200 g of MS. Therefore, this amount of Cl- found doesn’t represent a hazard
for crop growth but enriches the micronutrients uptake by plants in the water content.
It was observed that MS1 is the material with the highest content of nutrients per dried soil.
This condition does not guarantee that the releasing amounts of nutrients from molten slag isrelated to the mineral content in every type. Although MS2 does not have great amounts ofnutrients, it was observed that EC increased due to high amounts of Ca2+ released.
CONCLUSION
In this study, three varieties of molten slag under releasing treatment of nutrients for crop system
proved a remarkable difference among the quantities of nutrients released by every type of slag
analyzed. MS3 had performed the highest amounts of nutrients released by g of sample, findingthat the percentage of K+ available for plants is higher in MS3 than MS1 and MS2. Even when thecontent of Ca2+ is lower in MS2, the final concentration in the water was higher than the following
two samples, which can increase pH levels due to the chemical reactions of Ca 2+ when it contacts
water. It was indeed MS3 that released more Mg+ ions into the water and SO42- that can make adifference in plant nutrition. Certainly, PO42- is one of the major important anions for cropdevelopment yet low concentrations were found in this experiment: therefore, deep analysis and adifferent methodology should be considered to set the availability of this nutrient in crop systems.
It is expected that MS3 will perform better plant growth as it promises essential nutrients for plantdevelopment. Since the melting furnace is feed by same type of raw material, a comprehensive
study will be focused on the differences of every of system combined with analysis switching
sampling periods to confirm the releasing process.
ACKNOWLEDGEMENTS
The authors are grateful to KOBELCO ECO-SOLUTION Co., Ltd. for providing us the materials
for this study. This research was supported by Tokyo University of Agriculture.
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Czop, M. and Łaz’niewska-Piekarczyk, B. 2020. Use of slag from the combustion of solid municipal waste
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Devnita, R., Sandrawati, A. and Arifin, M. 2021. Utilization of steel slag in agriculture (Review). Soil REns,
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Dubey, S., Singh, A. and Kushwah, S.S. Utilization of iron and steel slag in building construction. AIP
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Kobayashi, J., Kizu, R. and Torii, K. 2004. Physical properties and metal elutions of the thirteen molten slags
produced from incinerated ash. Yakugaku Zasshi, 124 (9), 621-625, Retrieved from DOI https://doi.org/10.1248/yakushi.124.621
Marschner, P. and Rengel, Z. 2012. Nutrient availability in soils. Marschner’s Mineral Nutrition of Higher
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Research article
erdSome Physico-Chemical Characteristics of Surface Water in
Mining Areas in the Lao PDRSANTI KONGMANY*
Center of Excellence in Environment, Research and Academic Service Office,National University of Laos, Vientiane Capital, Lao PDR
Email: s.kongmany@nuol.edu.la

VANSENG CHOUNLAMANY
Faculty of Natural Sciences, National University of Laos, Vientiane Capital, Lao PDR

PHETYASONE XAYPANYA
Faculty of Water Resources, National University of Laos, Vientiane Capital, Lao PDR

OULAY PHOUPASONG
Faculty of Environmental Sciences, National University of Laos, Vientiane Capital, Lao PDR

BOUNTHOB PRAXAYSOMBATH
Faculty of Natural Sciences, National University of Laos, Vientiane Capital, Lao PDR

SINDAVANH PHENGTHAVANH
Information Compilation Division, Department of Mining Management,
Ministry of Energy and Mines, Vientiane Capital, Lao PDR
Received 22 February 2022

Accepted 25 April 2022(*Corresponding Author)

Abstract Lao People’s Democratic Republic (the Lao PDR), is naturally enriched withmineral resources having been the important potential in the country socio-economic
development. Mining activities for utilizing such resource is expected to bring not only
benefit but also environmental problems such as deforestation due to land opening, surface
water quality decline. The objective of this study was to initially investigate the surface
water quality of the two main rivers (Namkok and NamMo) near two mining areas (Sepon
and PhuBia) in Savannakhet and Xaysomboun provinces, respectively. Water samples from5 sampling sites on each river were analyzed for physical (pH, EC, temperature, turbidity,
TDS,) and chemical (alkalinity, DO, COD, inorganic cations and anions, and some heavy
metals) characteristics in two sampling times (May and July) in 2021. The finding results
unveiled that the water of the two rivers had temperature of 23-32oC, DO 8-16 mg/L and
COD 1.8-64 mg/L. The water pH, EC, and alkalinity were found at values of 7-8, 83-576µS/cm, and 48-174 mg-CaCO3/L ranges, respectively. In contrast, the amount of TDS in theboth rivers were 53-369 mg/L. The detected dominant cations were Na+, Ca2+ and Mg2+ andtheir concentration was in a concentration range of 0.5-34 mg/L, while main anions were F–, Cl– and SO42- (3-9 mg/L). The particulate matter content in the water in the form of TSS(67-372 mg/L) were observed. The presence of both TDS and TSS might lead to the water
turbidity of as low as 5 NTU or as high as 200 NTU. The investigated heavy metal
concentration was typically low. Based on the findings, the water quality of the two rivers
at the time of investigation was not beyond the Lao national environmental quality criteria.
Keywords physico-chemical characteristics, surface water, mining areas, the Lao PDR

INTRODUCTION
Lao People’s Democratic Republic (Lao PDR or Laos), a country in Indochina peninsula, has an
outstanding abundance of natural resources such as densely forest for reserving the water resourcesⒸ ISERD

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and its quality, nutrient-rich abundance for agriculture, streams for agricultural irrigation, humanbeing livelihood and water resources for hydropower development, precious minerals, charm andbeautiful tourist sites (Kiprop, 2019). If well managed and used, the natural resources wealthcontribute to the national development and bring benefit to Lao people (Vostroknutova, 2010).
Depositing in many parts of Laos, it has identified that more than 570 mining areas where gold,copper, zinc and lead covered around 47%, which are the socio-economic development potentials
of Laos (Kyophilvong, 2009). Two main mining companies in Laos are Lanxang Mineral Company
which have been operating at Vilabuly district of Savannakhet province since 1993, and PhuBia
Mining Company Limited which have been operating at Anuvong district of Xaysomboun province
since 1994 (Shibata, 2008).
The environmental impacts from mining is diverse, and various tools are needed formonitoring and assessing the impacts (Islam et al., 2020). Physical, biological and chemical
properties are the main components of water quality for assessing the mining caused impacts to thewater sources environment (Amin et al., 2016; Hirwa et al., 2019). The water quality assessment
could provide important information for protecting environment and people living downstream ofthe mining areas (Gerhardt et al., 2004). However, the mostly concerned river water pollution
caused by mining is the presence of heavy metals of which their concentration and distribution in
the surface water are dominated by the geochemical situation and the pollution source, but
seriously affected by mining leachate and chemical wastewater discharge (Liang et al., 2011).
Therefore, the inspection of mining companies which must follow the environmental standard
criteria and the participation of the publics in the water quality monitoring (WQM) might havechallenges beyond the environmental responsibility of the authorities: (1) scientific soundness, (2)political relevance and (3) harmonization in WQM implementation (Mercado-Garcia et al., 2019).
OBJECTIVE
The objective of this study was to investigate the physico-chemical characteristics of the mainrivers – NamKok and NamMo rivers near the two gold-copper mining areas in Vilabuly andAnuvong districts of Savannakhet and Xaysomboun provinces, respectively.
METHODOLOGY
Sampling Sites and Times
The physico-chemical characteristics of NamKok and NamMo were investigated in two samplingtimes – one in May and another in July as a representative of dry and rainy season in 2021. The
typical maps of the two mining areas where 5 selected sampling sites were marked are shown in
Fig. 1. The selected sampling sites are the same places where the water quality was also monitoredby the companies’ environmental monitoring units.
Sampling and Analytical Method
The water samples collected by grabbing method were either preserved or non-reserved and stored
in plastic sample bottles according to the parameters - alkalinity, hardness, chemical oxygen
demand (COD), inorganic cations and anions, and heavy metals for being analyzed in a laboratory.
During transportation to the laboratory, the all sample in the bottles were kept in an ice box withcooling packs. The electrical conductivity (EC), pH, dissolved oxygen (DO), temperature andturbidity of water samples was measured at the sampling sites using portable multi-parameter water
quality meter and turbidity meter. Total dissolved solids (TDS) was estimated from EC, while totalsuspended solid (TSS) was determined by Standard Methods 2540 D (dried at 103-105°C),
alkalinity, hardness by titrimetric method, COD by potassium dichromate method, inorganic
cations and anions by ion chromatographic method, heavy metals (Cu, Pb, Cr, As, Hg, Zn, Cd, Ni,Fe) by atomic absorption spectrometric method (APHA et al., 2017).
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Fig. 1 A typical topographic maps of 5 sampling sites in NamMo (NMo1-5) andNamKok (NKok1-5) in PhuBia and Sepon Mining Areas
RESULTS AND DISCUSSION
Temperature, pH, DO and Alkalinity
The comparison of temperature, pH, DO and Alkalinity for the two rivers (NamMo and NamKok)
are shown in Fig. 2. The temperature and pH characteristics of them were similar. In contrast,
NamKok’s DO and alkalinity was somehow higher than those of NamMo. The difference in theriver’s alkalinity in May and July would be due to their seasonal hydrological and geographicalcharacteristics. High alkalinity of these rivers would be good for high buffering capacity of thewater against change in pH (Weiner and Matthews, 2003), and this would be correlated to theobserved pH.

Fig. 2 Temperature, pH, DO and Alkalinity of NamMo (NMo1-5) andNamKok (NKok1-5) in May and July 2021
TDS, TSS, EC, Turbidity and CODⒸ ISERD

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The analytical results of the two rivers in terms of TDS, TSS, EC, turbidity and COD are shown in
Fig. 3. NamKok river showed its TDS and TSS characteristics higher than that of NamMo in May,but not much different in July, and this would lead to their similar properties on EC. For COD, bothrivers showed high values in opposite month, the reason is still unclear whether by the effect ofwater nature dilution or anthropogenic mining activities (Xu et al., 2020).

Fig. 3 TDS, TSS, EC, Turbidity and COD of NamMo (NMo1-5) andNamKok (NKok1-5) in May and July 2021

Fig. 4 Characteristics of Some heavy metals in NamMo (NMo1-5) andNamKok (NKok1-5) in May and July 2021

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Characteristics of Some Heavy Metals in NamMo and NamKok
The contamination of heavy metals in water resources nearby the mining operation activities is themost concerned as most of heavy metals are toxic even at very low concentration (Fashola et al.,2016; Liang et al., 2011; Mahato et al., 2017). In this study, the presence of less toxic metals (Fe,Cu, Zn) and much toxic metals (As, Cr, Cd, Ni, Pb, Hg) in NamMo and NamKok rivers were
investigated and the results are shown in Fig. 4.
The concentrations of heavy metals in NamKok river were mainly higher than those in
NamMo, except Zn and Ni. The Zn concentration in NamMo river was much higher than that in
NamKok and it is expected that Zn metal might be abundant in nature nearby the NamMo area.
Concerning As, its concentration in NamMo river was found similar in all 5 sampling sites
indicating that such presentation would occur naturally (Wurl et al., 2018).
In contrast, the presence of As in NamKok river in July in downstream was somehow higher
than those in upstream, indicating that leaching As from upstream area due to runoff would be
expected as the cause (Dai et al., 2013). Similarly, the concentration of Hg in water sampled at the
down-stream in both rivers was higher than those at upstream. The presence of Hg in the surface
water could occur through soil erosion, surface runoff, and land use in the mining areas (Dai et al.,2013). The presence of Cr in both NamMo and NamKok rivers is in similar characteristics, while
the highest concentration of Cr peaked at the middle stream. Furthermore, the presence of Cr insuch concentration in both rivers would be due to its natural occurrence (Chrysochoou et al., 2016;
Ferronato and Torretta, 2019; Mani Tripathi and Chaurasia, 2020). The presence of Ni in bothrivers was very low indicated by its concentration below the detection limit.
CONCLUSION
This study unveiled, even not completely, that the water quality of the two rivers - NamMo and
NamKok in the mining operation areas at the time of our investigation is still not in serious
situation according to their physico-chemical characteristics which were not beyond the limited
value in comparison to the Lao national environmental standard (2017) on surface water quality.
The water quality of the two rivers would be affected by the seasonal (May versus July) andgeographical (upstream versus downstream) difference. The results from this study could be used
as a fundamental scientific data for further study. However, it is recommended that more sampling
frequency and sites should be further taken into account for future investigation so that the water
characteristics would be more realistic.
ACKNOWLEDGEMENTS
The authors would like acknowledge the Second Strengthening Higher Education Project (SSHEP),
Department of Higher Education, Ministry of Education and Sports of Lao PDR for financial
support. Furthermore, Authors would like to thank Lanxang Mineral Mining Limited and PhuBia
mining companies for facilitating our team in site visiting and sample collection.
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Research article
erd

Potential Use of Predatory Bug Eocanthecona furcellata for
Biological Control of Plutella xylostella in Chinese Kale
Production
JUREEPORN SUKHATIPHUM
National Biological Control Research Center (NBCRC), Upper North eastern Regional Center,
Khon Kaen University, Thailand

PANIDA KRUAYSAWATNational Biological Control Research Center (NBCRC), Upper North eastern Regional Center,
Khon Kaen University, Thailand

NUTCHAREE SIRI
National Biological Control Research Center (NBCRC), Upper North eastern Regional Center,
Khon Kaen University, Thailand

PRAKAIJAN NIMKINGRAT
Department of Entomology and Plant Pathology, Faculty of Agriculture, Khon Kaen University,
ThailandUBON TANGKAWANIT*
Department of Entomology and Plant Pathology, Faculty of Agriculture, Khon Kaen University,
Thailand
Email: ubonta@kku.ac.th
Received 30 December 2021

Accepted 2 May 2022(*Corresponding Author)

Abstract Predatory bug Eocanthecona furcellata was investigated for the potential of
biological control agent to Plutella xylostella in the laboratory and greenhouse condition.
Predation rate of 3rd to 4th instar nymphs E. furcellata on 2nd, 3rd and 4th instar larvae P.
xylostella were studied in the laboratory. The results showed that predation rate of 4th and5th nymphal instars of E. furcellata were higher than 3rd instar. Feeding rate were greater
when they feed on 2nd and 3rd instar larvae than feed on 4th instar larvae of P. xylostella. The
efficiency of E. furcellata in controlling P. xylostella under greenhouse conditions was
conducted. When P. xylostella population reached to economic threshold (ET), 20 of E.
furcellata were released to chinese kale greenhouse (18 m3), Results showed that pest
population was reduced 10.32% after 5 days of release when compared to control.
Additionally, percentage of plant damage from released predatory bug greenhouse waslower than non-released greenhouse. Therefore, it is possible to release the predatory bug E.
furcellata in vegetable production as a biological control agent.
Keywords predation, biological control, diamondback moth

INTRODUCTION
Plutella xylostella (L.) is an important pest to Brassicaceae including Chinese kale (Brassica
oleracea var. alboglabra). The first instar larvae feed on mesophyll tissues inside the leaf, whereas,other instar larvae are surface feeders. They consume leaves, buds, flowers, siliques, and the green
outer layer of stems (Sarfraz et al., 2005). The damage varies, depending on plant growth stage,
plant varieties, larval densities and size. If larvae are numerous, they can consume the entire leaf
except the veins. P. xylostella has been a serious pest of vegetable crops for many decades. The
annual cost for its global control is estimated at US$ 4-5 billion per year (Zalucki et al., 2012). The
short generation time, high fecundity and broad host usage within Brassicaceae host plant of P.
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IJERD – International Journal of Environmental and Rural Development (2022) 13-1xylostella are the important factors for insecticide resistance for example chlorantraniliprole,
Spinosad, chlorfenapyr and lufenuron, an insect growth regulator (IGR) (Arruda et al., 2020).
A method to delay the evolution of insecticide resistance is to integrate the use of control
methods such as chemical and biological controls (Mccord and Yu, 1987). Eocanthecona furcellata
Wolff (Hemiptera: Pentatomidae) is a common predatory stink bug in Southeast Asia (Tuan et al.,2016). It has been mass-reared and used as a biological control agent in Thailand (Suasa-ard, 2010).
It has been reported for controlling many caterpillars worm such as Mythimna separata,
Helicoverpa armigera, and Heliothis assulta etc. Predation of E. furcellata gradually increased
from the 2nd instar to 5th instar nymph when fed on Maruca vitrata (Pillai and Agnihotri, 2013) andSpodoptera litura (Tuan et al., 2016). Even though, there are some studies of feeding efficiency
and utilization of E. furcellata for many insect pests, there are not many studies of E. furcellata fed
on P. xylostella. Tuan et al. (2016) revealed predation rate of each stage and life table of E.
furcellata when fed on 4th larval instar but not all stage. Therefore, this study revealed the predation
rate for 3rd -5th nymphal stages of E. furcellata when fed on 2nd-4th larval stages of P. xylostella forfinding suitable stages for biological control. Additionally, E. furcellata was evaluated for its
efficiency as a biological control agent in the greenhouse.
OBJECTIVE
The objectives of this study were to examine predation rate of the E. furcellata in predation life
stages and to evaluate its efficiency as a biological control agent in the chinese kale greenhouse.
METHODOLOGY
Insect Rearing
Plutella xylostella was collected from chinese kale production area in Khon Kaen Province,
Thailand. Thirty larvae were transferred in an aluminum cage (90x 60x 60 cm) with 15 days oldchinese kale in a pot inside the cage. The larvae were maintained in the cage until they became topupae. Pupae were transferred to the mating cage (10 cm in diameter and 10 cm in height). Newly
emerged adults were provided with cotton balls soaked with 20% honey water as food source.
Shredded of chinese kale leaves was used as the substrate for oviposition by the diamondback mothand the F3 was then used in the experiment. E. furcellata were taken from a colony (10thgeneration) maintained at NBCRC, Upper Northeastern Regional Center. The experimental insect
was maintained in the laboratory at room temperature, 28 ± 5°C, relative humidity of 60 ± 10%.
BioassayLaboratory: The experiment was examined in the laboratory using Completely Randomized
Design (CRD) with 10 replications. A newly hatched of 3rd, 4th and 5th nymphs of E. furcellata weretest for predation rate. One of each nymph was transferred into a container (7x 9x 4 cm) withcotton balls soaked with water, and a chinese kale leaf. Second larval instar of P. xylostella (n = 20)
were provided daily as a food until predator change to a new nymphal stage. Then, the experiments
were repeated, 3rd and 4th instar larvae of P. xylostella were provided instead as a pray. Predation
rate were recorded every day until E. furcellata change to new nymphal stage. The data were
statistically analyzed using Statistix 10 (Analytical software, 2013) and treatments were comparedusing Tukey's HSD test (P < 0.05).
Greenhouse: The experiment was examined in the 8 chinese kale greenhouses (18 m3) at NBCRC.
Forty pots of chinese kale were use as the experimental units for each greenhouse. The populationof P. xylostella was artificial infestation by releasing a cluster of eggs/pot when plants were 30 days
old. After eggs hatched to the larvae, the population were recorded. When the population reached tothe economic threshold level (ET) (1 larva/plant), Twenty of E. furcellata were released into theⒸ ISERD

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greenhouse. While, control greenhouse was not released. The experiment was studied with 4
replications. The data were statistically analyzed using Paired sample t-test using Statistix 10(Analytical software, 2013). Percentage of leaf area damage was recorded in level of injury (0=nodamage, 1 = < 25% damage, 2 = 25-50% damage, 3 = 50-75% damage, 4 = >75% damage). The
percent reduction of P. xylostella was statistically calculated according to the equation ofHenderson and Tilton (1955).
(1)
Where, Ta = population of insect counts after treatment, Cb = population of untreated insect
count before treatment, Tb = population of insect counts before treatment, and Ca = population of
untreated insect count after treatment.
RESULTS AND DISCUSSION
Prey consumption of E. furcellata fed on larvae of P. xylostella was significantly different. The
third nymphal instar of E. furcellata fed on 3rd and 4th instar larvae more than 2nd instar larvae,
whereas, 4th and 5th nymphal instar of E. furcellata fed on younger more than the older prey (Table1). Predation rate of E. furcellata may involve with a prey species. Tiwari et al. (2017) revealed
that when E. furcellata fed on S. litura, and M. vitrata, predation rate of prey consumed slightly
increased with increasing prey stage. However, when E. furcellata fed on Spilarctia obliqua and S.
frugiperda predation rate of prey consume decreased with increasing prey size (Kumar et al., 2001;
Keerthi et al., 2020). Rani and Wakamura 1993 suggested that physical stimuli such as host shapeor movement had no influence on acceptability of the prey to E. furcellata.
Table 1 Prey consumption of different stages of Eocanthecona furcellata fed
on larvae of Plutella xylostella
P. xylostella 1/

Treatment
E. furcellata

2nd instar

3rd instar

4th instar

3rd nymph
4th nymph
5th nymph
F-testCV (%)

28±0.50 B
71±5.91 A
71±2.65 A**
24.33

65±4.50 A
79±4.72 A
60±5.35 AB
**
30.28

50±1.91 A
24±0.82 B
38±2.08 B*
26.08

1/Within each column, mean±SD followed by the same capital letter indicate

no significantly different (P>0.05)

However, Kumar et al. (2001) revealed that visualization of the predator and movement of
prey increases the predation rate. In this case, the active movement of 2 nd and 3rd instar larvae of P.
xylostella may be a factor of high predation rate of 4th and 5th nymphal stage of predator. Contrast
to 4th and 5th nymphal stage, 3rd nymphal stage may difficult to handle the active prey movement.
The results of laboratory experiment for predation of E. furcellata lead to a decision to releaserd
3 nymphal stage of E. furcellata as a biological control in chinese kale greenhouse. Twenty of 3rd
nymphal stage in a bio-product were released into the greenhouse after diamond back moth reachto 1 larva/plant. The results revealed that the number of P. xylostella was not significant different
between treatment and control (Table 2). However, population of P. xylostella was reduced at 3days after E. furcellata released. The percent reduction of P. xylostella at 3-5 day after predator
released were 10.32, 21.79 and 18.06%, respectively. During 1-2 days after predator released the
population in treatment was not reduced. At that period, most of P. xylostella was 2nd instar which
was not suitable for the predator stage. Two day later, most of pest population was 3rd instar, andpredator was changing nymphal stage from 3rd to 4th nymph. Then the population was reduced(Percent reduction was higher). Therefore, in case of a serious outbreak, 4 th nymphal stage may useⒸ ISERD

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instead. Level of chinese kale leaf damage in control greenhouse increased from level 1 to level 3,
whereas, level of chinese kale leaf damage in control greenhouse was level 1 and level 2.
However, applying in open field condition may have some factors such as temperature,various pests, other natural enemies and chemical insecticide which involving the efficiency of
predator.
Table 2 Number of Plutella xylostella in chinese kale greenhouse and level of leave damage
with released and non-released Eocanthecona furcellata as a biological control
agent, and percentage reduction.
Plant age(day)

non-released
Insect/plant

362/
37
38
39
40
41

2.32±1.15a1/
2.21±1.12a
2.17±1.09a
2.12±1.04a
2.06±1.00a
1.75±1.00a

Level of leavedamage111223

released
Insect/plant
1.44±0.15a
1.42±0.14a
1.40±0.15a
1.18±0.18a
1.00±0.26a
0.89±0.24a

Reduction (%)

Level of leavedamage
1
1
1
1
1
2

na
-3.52
-3.94
10.32
21.79
18.06

1/Within each row, mean±SD followed by the same small letter indicate no significantly different (P>0.05)
2/ Eocanthecona furcellata was released into the greenhouse.

CONCLUSION
E. furcellata is an effective predator of P. xylostella, the third nymphal stage consumed 3rd and 4thlarval instar than 2nd instar. In contrast, 4th and 5th nymphal stage consumed 2nd and 3rd instar morethan 4th instar. E. furcellata is an alternative biological control agent in chinese kale green house. It
can reduce pest population and level of leaf damage.
ACKNOWLEDGEMENTS
This study was funded by National Research Council of Thailand (NRCT). We are grateful to the
National Biological Control Research Center (NBCRC), Upper North-Eastern Regional Center,
Thailand for the experimental area and supplying specimen of E. furcellata.
REFERENCES
Arruda, S.L., Rodrigues, R.S.A., Bermudez, C.B.N., Ribeiro, M.S.L., Neto, L.E.J. and Siqueira, A.A.H. 2020.
Field resistance of Plutella xylostella (Lepidoptera: Plutellidae) to lufenuron: Inheritance and lack of
cross-resistance to methoxyfenozide. Crop Protection, 136, 105237, Retrieved from DOI https://doi.org/
10.1016/j.cropro.2020.105237
Kumar, V., Morrison, N.M., Rajadurai, S., Babu, M.A., Thiagarajan, V. and Datta, K.R. 2001. Studies on the
biology and predatory behaviour of Eocanthecona furcellata (Wolff.) predating on Spilarctia obliqua(Walk.) in mulberry plantation. International Journal of Industrial Entomology, 2 (2), 173-180.
Maccord, E. 1987. The mechanisms of carbaryl resistance in the fall armyworm, Spodoptera frugiperda (J. E.
Smith). Pesticide Biochemistry and Physiology, 27 (1), 114-122.
Pillai, A.K. and Agnihotri, M. 2013. Biology and predatory potential of Eocanthecona furcellata (Wolff.) on
Maruca vitrata geyer. Madras Agricultural Journal, 100, 193-195.
Rani, U.S. and Wakamura, S. 1993. Host acceptance behaviour of a predatory pentatomid, Eocanthecona
Furcellata (Wolff) (Heteroptera: Pentatomidae) towards larvae of Spodoptera Litura (Lepidoptera:
Noctuidae). International Journal of Tropical Insect Science, 14 (2), 141-147, Retrieved from DOI
https://doi.org/10.1017/S1742758400014521
Sarfraz, M., Keddie, B.A. and Dosdall, M.L. 2005. Biological control of the diamondback moth, Plutellaxylostella: A review. Biocontrol Science and Technology, 15 (8), 763-789, Retrieved from DOI https://doi.org/10.1080/09583150500136956Ⓒ ISERD

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Suasa-ard and National Biological Control Research Center (NBCRC), 2010. Natural enemies of important
insectpests of field crops and utilization as biological control agents in Thailand. Retrieved fromhttps://www.naro.affrc.go.jp/archive/niaes/sinfo/sympo/h22/1109/paper_12.pdf
Tiwari, S., Maurya, R. and Pandey, K.A. 2017. Effect of different insect hosts on biology and predation
efficiency of Eocanthecona furcellata Wolff (Hemiptera: Pentatomidae). The Bioscan, 12 (1), 193-197.
Tuan, S., Yeh, C., Atlihan, R. and Chi, H. 2016. Linking life table and predation rate for biological control: A
comparative study of Eocanthecona furcellata (Hemiptera: Pentatomidae) fed on Spodoptera litura(Lepidoptera: Noctuidae) and Plutella xylostella (Lepidoptera: Plutellidae). Journal of Economic
Entomology, 109 (1), 13-24, Retrieved from DOI https://doi.org/10.1093/jee/tov265
Zalucki, P.M., Shabbir, A., Silva, R., Adamson, D., Liu, S. and Furlong, J.M. 2012. Estimating the economic
costof one of the world's major insect pests, Plutella xylostella (Lepidoptera: Plutellidae), Just how longis a pieceof string? Journal of Economic Entomology, 105 (4), 1115-1129, Retrieved from DOI http://dx.doi.org/10.1603/EC12107Ⓒ ISERD

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Research article
erd

Improving Water Quality of a University-Managed Biotope
MADOKA KUROTAKI
Graduate School of Agro-Enviromental Science, Tokyo University of Agriculture, Japan
Email:12521002@nodai.ac.jp

MACHITO MIHARA*
Faculty of Regional Enviroment Science, Tokyo University of Agriculture, Japan
Email:m-mihara@nodai.ac.jp
Received 16 January 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract “Biotope” was coined in Germany by combining the ancient Greek word “Bios”,
which refers to organisms and life, and “Topos”, which refers to a place. In Germany,
biotopes have been attracting attention since the 1970s, when environmental problems
caused by industrialization became more serious. Since the end of the 20th century,
biotopes have been created in various parts of Japan, including tidal flats, wetlands, lakes,
rivers, and other water bodies, as well as forests and grasslands. It is still offered as an
educational opportunity in Japan. They are prone to water pollution and need to be
improved because biotopes are closed environmental water bodies. In Japan, there is no set
environmental level for the water quality of biotopes. In this study, we conducted water
quality measurement and purification experiments in the biotope in the campus at Tokyo
University of Agriculture, Japan. This study aims to evaluate total nitrogen in a biotope.
The biotope at Tokyo University of Agriculture had not been managed regularly for a longtime. First, the filtration system installed in the biotope was not working, so it was fixed.
For measuring water quality, water samples of the biotope at Tokyo University ofAgriculture were collected twice a week in a month. And the concentrations of total
nitrogen (TN) were measured by a spectrophotometer. In the biotope at Tokyo Universityof Agriculture, total nitrogen ranged from 1.14 to 3.76 mg/L, which is high compared to theenvironmental level set by the Ministry of the Environment for lakes and marshes in Japan.
Through a set of field observation, this study attempted to improve the water quality thebiotope at Tokyo University of Agriculture, which has been unmanaged for more than longyears. Water quality measurement and purification experiment revealed that total nitrogen
was improved.
Keywords biotope, water quality, filtration system, total nitrogen

INTRODUCTION
Water pollution is one of the most important environmental problems that have a wide range ofeffects such as the reduction of fishery resources, as well as the formation of ecosystems. Water
pollution can be divided into two major categories: first, water pollution caused by toxic substancesand pathogens that threaten human health. The first is water pollution caused by toxic substancesand pathogens that threaten human health, such as heavy metals, cyanide, and contagious
pathogens such as dysentery and cholera. Secondly, water pollution caused by excrement andorganic matter discharged by people's daily activities. In addition, eutrophication caused by therunoff of phosphorus and nitrogen contained in pesticides and fossil fuels in closed environmental
water bodies such as lakes and marshes result in massive algae blooms that affect many aquaticorganisms and cause significant economic losses to fisheries and other human production activities.
Japan has been taking proactive measures to deal with the water quality environment since theperiod of high economic growth in the 1970s. As a result, the non-achievement rate ofenvironmental standards for substances that affect the human body such as heavy metals, cyanide,Ⓒ ISERD

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organic compounds, and pesticides (health items) in public water bodies is 0.79%, which can besaid to be almost achieved.
On the other hand, however, the rate of achievement of environmental standards for living
environment items such as biochemical oxygen demand (BOD) and chemical oxygen demand(COD) has not been sufficiently achieved. The percentage of pollution load including domestic
wastewater, waste, livestock wastewater, and small-scale business wastewater generated frompeople's production activities is still high.
Since the late 1960s, organic pollution in rivers has been improving, but the status ofachievement of environmental standards for phosphorus and nitrogen in lakes and marshes remains
low at around 50%, although there have been signs of improvement in recent years.
As for chemical oxygen demand (COD), one of the representative indicators of organic
pollution, the rate of achievement of environmental standards in lakes and marshes in FY2039 was
50.0%, a decrease of 4.3 percentage points from the previous year. Looking at the trends since
1979, COD was almost flat in the upper half of the 3 mg/L range before 2002, but has been in theupper half of the 3 mg/L range since 2003, and was 3.3 mg/L in the first year of 2003.
As for total nitrogen and total phosphorus in lakes, the achievement rate of the environmental
standard was 49.2%. This is an increase of 0.4 percentage points from the previous year. The
achievement rate for total nitrogen was 21.4%, while the achievement rate for total phosphorus was
50.8%.
The environmental standard attainment rate of 50.0% for lakes is still low compared to rivers
and seas. It is said that the achievement rate of closed environmental water bodies is lower than thatof other water bodies due to the fact that closed environmental water bodies have a large pollution
load that flows in and accumulates easily. It can be said that measures to deal with nitrogen andphosphorus in domestic wastewater, which contribute to this, are a major issue. In particular, lakes
and dammed lakes are often the source of water for water supply, and this causes problems such as
moldy odor, filtration problems caused by blue-green algae, and bad odor.
The main source of pollution in Japan is domestic wastewater from cooking, washing, bathing,
and urination. About 60% of the pollution load flowing into closed environmental water bodies
comes from domestic wastewater, and the load from domestic miscellaneous wastewater(excluding urine) is particularly large. Domestic wastewater from households, such as cooking,washing, bathing, and urination, is an important source of water pollution in public water bodies.
However, if we look at the sources of pollution in terms of nitrogen and phosphorus rather
than BOD, manure accounts for a high percentage of 80% and 60%, respectively. This raises thequestion of the importance of countermeasures.
On the other hand, measures to deal with the pollution load discharged from a wide range ofsources such as farmland and forests are also considered important. It is said that 20% of the total
pollution load flowing into lakes and marshes comes from this wide area, but the priority ofmeasures remains low due to the current high pollution load from domestic wastewater.
When we took water samples from the biotope on the university campus and measured themin a class, they did not meet the total nitrogen and total phosphorus standards of the“Environmental Standards for the Conservation of the Living Environment for Lakes and Marshes”(Ministry of the Environment). We were also interested in the water quality of closed
environmental water bodies such as lakes and marshes, so we chose a biotope, which can beconsidered a closed environmental water body, as my target site.
The term "biotope" was coined in Germany by combining the ancient Greek words “Bios”
meaning organism or life and "Topos" meaning place. In Germany, biotopes have been attracting
attention since the 1970s, when environmental problems caused by industrialization became more
serious. In Japan, too, biotopes have been created in various places since the end of the 20th
century, including water bodies such as tidal flats, wetlands, lakes, and rivers, as well as forests andgrasslands. Since biotopes are closed environmental water bodies, they are prone to water pollution
and need to be improved.

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OBJECTIVE
Our biotope itself was artificially created. However, because it had been neglected for many years,
the surrounding vegetation had become overgrown and desolate. The filtration system itself had
deteriorated and was not functioning as it should, with pumps and other equipment failing. In
addition, with the construction of the surrounding facilities, the biotope itself was reduced in size,
and the flow of water that should have been there was lost, resulting in the current situation
This study aims to evaluate total nitrogen of this biotope, compare it to the environmental
standard and examine the filtration capacity of the filter.
METHODOLOGY
The biotope in the campus of Tokyo University of Agriculture is divided into two main areas: theChitose Gate side is called the back and the Ichigokan side is called the front in this study.
The back of the biotope and the front of the biotope are connected by a siphon to keep thewater level constant. The water supply at the back of the biotope brings in new water. In addition, afully automatic upward-flow rapid filtration machine is installed near the back of the biotope. It
operates from 8:00 a.m. to 8:00 p.m. and absorbs sludge from the back of the biotope and drains thefiltered water to the back of the biotope.
Since the biotope itself had been neglected for many years and we could not even recognize its
original shape, we decided to clean and repair it. We collected fallen leaves floating on the surfaceof the biotope and cut down the surrounding trees.
It was repaired the deteriorated fully automatic upward-flow rapid filtration system. It was
repaired the malfunctioning pump, cleaned the siphon, cleaned the water intake and drainage pipes,
loaded filter media, replaced the filter, and installed a filter on the water intake pipe. The work was
carried out over October 16, October 26, October 30, and November 9. The normal operation of thepump was confirmed on November 9.
Water samples were taken periodically for about a month at the biotope on the campus ofTokyo University of Agriculture, the target site. Starting on October 27, water samples were takenin the morning of October 30, November 3, November 6, November 10, November 13, November
17, November 20, and November 24, and measurements were taken in the afternoon.
The water samples were placed in containers marked with the date of collection and stored ina refrigerator. The total nitrogen concentration was measured by absorption spectrophotometry
using the HC-1000 eutrophotometer. The dilution ratio for total nitrogen concentration
measurement was 5 times. In the alkaline potassium peroxodisulfate decomposition and UV
absorption method used here, sodium hydroxide and potassium peroxodisulfate are added to thesample water, and the water is autoclaved (132℃, 30 min) to oxidize and decompose all nitrogencompounds and replace them with nitrate ions. Then, the absorbance at the wavelength targeted fornitrate ions is measured and determined as the total nitrogen concentration. For the total nitrogenconcentration, the following Equation (1) was used to correct the reading value.
Total nitrogen concentration (mg/L) = reading x dilution factor x 1.2(1)

RESULTS AND DISCUSSION
After repairing the biotope by collecting fallen leaves on the surface of the water and cutting down
the surrounding trees, the water area of the biotope became clearly wider than before. Since thebiotope had been neglected for many years, it was confirmed that sludge had accumulated in the
biotope itself and metals had been dissolved.
In addition, shellfish and goldfish were found living in the water of the biotope. Since thebiotope was artificially created, it is unlikely that shellfish and goldfish came from nature to live
there. Therefore, we think it is more likely that they were introduced artificially to improve water
quality. We also saw other aquatic plants that had been planted on the tires. The plastic covers thatcovered the pipes were also observed in the water.
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Total nitrogen showed a decreasing trend after the collection of fallen leaves on the 30th ofOctober. This is thought to be because the fallen leaves that were floating on the water surface werecollected and did not accumulate on the bottom of the water without decomposing in the water. As
was confirmed during the cleanup, the bottom of the biotope was filled with a sludge-like substance
where fallen leaves had sunk and decomposed. We believe that these had a lot to do with the water
quality of the biotope and also affected the total nitrogen value. The values were on the increase
after the collection of fallen leaves once on October 30. Since it is impossible to completely
remove trees and leaves, we think that fallen leaves accumulated on the water surface again,
sinking and turning into sludge, which affected the values.
Biotope back(Chitose Gate side)

4
3.5
3
2.5
2
1.5

1
0.5
0
23-Oct-20

28-Oct-20

2-Nov-20

7-Nov-20

12-Nov-20

17-Nov-20

22-Nov-20

TN

Fig. 1 Changes in total nitrogen concentration at Biotope back (Chitose Gate side)
Biotope front(Ichigokan side)
4
3.5
3
2.5
2
1.5
1

0.5
0
23-Oct-20

28-Oct-20

2-Nov-20

7-Nov-20

12-Nov-20

17-Nov-20

22-Nov-20

TN

Fig. 2 Changes in total nitrogen concentration at Biotope front (Ichigokan side)
On the other hand, the values have been on a downward trend since November 9, when thepump was confirmed to be in operation. This is thought to be due to the fact that the fullyautomatic upward-flow rapid filtration system works by filtering out mud and pollutants from thewater, which lowers the value of total nitrogen.
The total nitrogen obtained in this study was compared with the “Environmental Standard for
the Conservation of Living Environment (Lakes and Marshes)” of the Ministry of the Environment.
The total nitrogen was less than 1 mg/L, which means that the item type is classified as V. In otherwords, it can be said that the adaptability of the purpose of use lies in industrial and agricultural
water use.
However, the total nitrogen obtained in this study was very high, ranging from 2.0 to 3.0 mg/L,
compared to the standard of 1 mg/L or less. We think that humus and decomposing matter are thepossible causes of the high total nitrogen value in the biotope. The fact that the collection of fallen
leaves on the surface of the water and the cutting down of trees had a great effect on the decrease of
the total nitrogen value, and the fact that rotten fallen leaves were accumulated on the bottom of thebiotope, led us to the above conclusion.
We heard that many people had dealt with the water quality improvement of biotopes as atheme for their graduation thesis or research in the past. Because of this, there were many shellfish,
plants, and other things left in the biotope that would have been used for research in the past. In
addition, the biotope has been reduced in size due to the construction of neighboring facilities, andthe water flow that should have been there has been lost, which may have affected the water quality.
In fact, by cleaning the biotope and adding new water, the water area has become much wider than
before the repair.
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CONCLUSION
Seeing the state of the biotope, which had been neglected to the point of changing its shape, westrongly considered the importance of maintenance and management. In this study, the fully
automatic upward-flow rapid filtration machine, which had been repaired and was now working
properly, can be said to have fully fulfilled its purification function and contributed to theimprovement of water quality. The filter media, which is considered a consumable item, had notbeen replaced, and the filtration was not working because it had not been inspected or repaired.
wen the future, it will be important to check and replace the filter media on a regular basis.
In this study, we thought that the total nitrogen value decreased by collecting fallen leaves. In
order to prevent leaves from falling in the future, it would be a good idea to install a net. However,
it is necessary to manualize and periodically repair the system, since it could be left for a long timeand deteriorate, causing water pollution.
Also, it was considered that such measures for the maintenance and management of thebiotope should have already been incorporated into the plan when it was artificially created. If thequality of water and the environment of the biotope is the first priority, it is necessary to clean andrepair the biotope on a regular basis as we did in this study. If it is difficult to do so, we have toconsider the possibility of removing them.
ACKNOWLEDGEMENTS
We would like to express my sincere gratitude to Associate Professor Toru NAKAJIMA for his
guidance from the conception of the research to the experimental methods and writing of the paper,
despite their busy schedules.
We would also like to express my deepest gratitude to Professor Atsushi TAJIMA and his
team of the Biorobotics Laboratory for their cooperation in repairing the biotope and filter.
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go.jp/water/suiiki/r1/r1-2.pdf, received date 2021-01
Ministry of the Environment 2022. Environmental standards for water pollution. Ministry of the Environment,
Japan, Retrieved from https://www.env.go.jp/kijun/wt2-1-2.html
Ministry of the Environment 2022. Appendix of environmental standards for water pollution. Ministry of theEnvironment, Japan, Retrieved from https://www.env.go.jp/kijun/mizu.htmlⒸ ISERD

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Research article
erd

Design and Experimental Analysis of Atmospheric Water
Generator Based on the Climatic Conditions of Manolo
Fortich, Bukidnon
TAN JERICO D.*
Mindanao State University-Iligan Institute of Technology, Iligan City, Philippines
Email: jerico.tan@g.msuiit.edu.ph

ALBIENTO ELIZABETH EDAN M.
Mindanao State University-Iligan Institute of Technology, Iligan City, Philippines
Received 29 January 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract Most Filipinos living in remote rural and island communities rely on unsafe
drinking water sources due to a lack of reliable water supply. With this, an atmosphericwater generator (AWG) can become an alternative water source by condensing andcollecting water vapour present in the air. However, previous research on the design of
AWG devices was conducted outside the Philippines and most studies did not design thelongitudinal profile of the fins and intake fan component of the device. This study designed
the longitudinal fin profile of the fins and intake fan speed based on the climatic conditionsof Manolo Fortich, Bukidnon and analysed the performance of the device by conducting afield experiment. The study designed the extended fins and varied the intake fan speed byconducting a parametric analysis using existing heat and mass transfer equations. The study
then conducted a field experiment of the AWG device by placing the device in a secure
open space. Results of the design showed that the 9 cm fin length was optimal for thedevice and that higher intake fan speed were more suitable for high relative humidity (RH)
and high air temperature conditions. Results from the field experiment showed that higher
water productivity was observed at higher RH level compared the lower RH levels. The
study concludes that a longer length of copper fins and greater magnitude of intake fan
speed does not necessarily translate to higher water productivity and that higher waterproduction rates were observed during high RH levels.
Keywords atmospheric water generator, Peltier effect, thermoelectric couple

INTRODUCTION
Potable water is a necessity for us humans to live. However, most of the river systems in thePhilippines face severe problems of pollution, which resulted in the higher cost of the supply of
potable water throughout the country (Rola et al., 2015). One way to obtain water cheaply andsustainably is to produce water out of air through condensation by using an atmospheric water
generator technology (AWG) with the use of thermoelectric couples (TEC).
AWGs are comprised of several components. The TEC is the main cooling unit which consistsof a cold surface on one side and a hot surface on the other side when an electric current is passed
thru the device. Copper fins are attached to the cold side to increase the surface area of the cold
surface. A fan is installed to suck in air into the device for air to come in contact with the cold
copper surface making the water vapor condense in these areas. Only around 1% of the carbon
dioxide (CO2) present in the air will dissolve in condensed water vapor to form carbonic acid
(H2CO3) making the water acidic with a pH as low as 5.5 (Bauer et al., 1980). With this, copper
pitting due to carbonic acid is less likely to occur at a lower PH of water (Taxen, 2002). The study
did not delve deeper in the extent of the effect of carbonic acid on the copper fins. The hot side isusually installed with an aluminum heat sink to dissipate the heat produced by the TEC. However,
little work has been done on the design of two major components of the AWG namely the cold side
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copper fins and the intake fan and most of the studies were designed outside the Philippines. In thisstudy, the length of copper fins was optimized and the intake fan speed was varied based on
Philippine climatic conditions and analyzed its performance in an actual field experiment.
OBJECTIVE
The main objective of this study is to optimize the design of an AWG device based on the climaticconditions of Manolo Fortich, Bukidnon. Specifically, the study will optimize the length of copper
fins, identify the appropriate intake air velocity considering a maximum air velocity, fabricate the
AWG prototype, and analyze the field test results of the AWG device.
METHODOLOGY
Optimization of Length of Copper Fins
The study initially acquired climatic data for Manolo Fortich, Bukidnon. The average values of thelowest, median and highest temperature and relative humidity were computed and determined the
dewpoint temperatures using these values. The study then considered four different lengths ofcopper fins namely 8 cm, 9 cm, 10 cm and 11 cm. To maximize the amount of water generated in
the device, all the surface area along the length of the copper fin should be less than the dewpointtemperature for maximum water condensation. Hence, the study performed a parametric analysis insolving the temperature distribution along the fins, using Equation 1, by using different fins lengths
and different climatic conditions. The temperature distribution equation was emulated from thestudy of Shourideh et al. (2018) and Kilic and Onat (1981). The lengths of fin 8 cm, 9 cm, 10 cm
and 11 cm that has a temperature distribution below the dewpoint at different climatic conditions
were chosen as the optimized length of copper fins.
(1)
Where m is fin parameter, T local fin temperature (K), Ta temperature of the surrounding air(K), hm mass transfer coefficient (m/s), hfg* modified latent heat of vaporization (J/kg), h convective
heat transfer (W/m2-K), Rv ideal gas constant (J/kg-K), Ta temperature of the surrounding air (K),
Pv,Ta partial pressure of water vapour in the surrounding air, and Pv,T partial pressure of water
vapour in the fin surface.
Also, the boundary conditions for Equation 1 were shown in Equation 2 and Equation 3.
(2)(3)
Where Lf is length of fins (m) and T0 initial cold side temperature of TEC (K).
Variation of Intake Air Velocity
The study also conducted a parametric analysis to compute the theoretical water generation rate byusing different values of air velocity considering a maximum velocity of 4 m/s at different climaticconditions. The study utilized the equation shown in Equation 4 to compute the theoretical water
generation rate. There were five cases of combinations of temperature and RH used in the analysis.
The intake air velocity that gave the maximum water generation rate was chosen as the appropriate
intake air velocity at that certain climatic condition.
(4)Ⓒ ISERD

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Where V is water generation rate (m3/s), ρl the density of water (kg/m3) and N number of finsattached to the TEC.
RESULTS AND DISCUSSION
Optimized Length of Copper Fins
Parametric analysis for the temperature distribution of the 8 cm, 9 cm, 10 cm and 11 cm lengths ofcopper fins for different climatic conditions were computed. Fig. 1 shows the results of thetemperature distribution of each of the copper fin lengths. It can be observed in Fig. 1 (b) that the
10cm and 11cm fin lengths exceeded the dewpoint temperature at 80% percent of its length. This
meant that the surface temperature beyond this point was higher compared to the dewpointtemperature at that climatic condition. Hence, the water does not condense in these regions and thecopper fins can be considered as partially wet fins under these conditions since not all of its surface
area can condense water.

Fig. 1 Fin temperature distribution of different fin lengths at(a) Ta=23 C and RH =90%, (b) Ta=31.4 C and RH=70%
On the other hand, it can be seen in Fig. 2 that the 9 cm fin length did not reach the dewpointtemperature in all cases of climatic conditions. This meant that all the surface area of the 9 cm
length copper fins can condense water vapor. Hence, the optimum length of the copper fins that
was also incorporated in the design of the AWG was the 9cm length.
Variation of Intake Air Velocity
Table 1 presents the cases used in the analysis with different ambient air temperatures and variable
RH levels.
Table 1 Summary of cases of temperature and RH used in the analysis
Case No. Ta (oC) RH 1 (%) RH 2 (%) RH 3 (%) RH 4 (%)
1
2
3
4

23.00
25.00
29.00
31.00

80.00
75.00
75.00
75.00

85.00
80.00
80.00
80.00

90.00
85.00
85.00
85.00

90.00
90.00
90.00

By applying these cases in the computation along with different variations of intake air
velocity considering a maximum velocity of 4 m/s, the theoretical water generation rate wasobtained and the results were shown in Fig. 2. It can be observed from the results that increasing
the air velocity generally increases the water generation rate for most of the cases presented.
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Fig. 2 Theoretical Water Generation Rate at different Air Velocitiesfor (a) Case 1, (b) Case 2, (c) Case 3, (d) Case 4, and (e) Case 5
For Case 1 and Case 2, there was low ambient air temperature paired with low RH levels. It
can be observed in Fig. 2 (a) and (b) that between RH of 75% to 80%, the water generation rateincreased initially when the air velocity was also increased but then decreased at higher magnitudesof air velocity. Hence, the air velocity of the fans can be adjusted at peak water generation rate
when the AWG device is subjected to low relative humidity such as in Case 1 and Case 2.
For Case 3 and Case 4, the increase in air velocity also increases the of water generation rate.
For this case, the increase in the value of the mass transfer coefficient resulting from the increase in
air velocity outweighed the decrease in the difference between the partial pressure of thesurrounding air and partial pressure at the fin surface.
Based from the results shown in Fig. 2, Table 2 summarizes the appropriate intake air velocity
at different climatic conditions. The values indicated in Table 2 were then incorporated into thedesign of the AWG in which the air velocity varied depending on the climatic conditions.
Table 2 Summary of appropriate air velocity at different climatic conditions
Relative
humidity
75%<80%80%<85%85%<90%90% < 100%

23°C ≤ 24°C
0.00
0.60
2.00
4.00

Intake air velocity (m/s)
24°C ≤ 26°C
26°C ≤ 28°C
0.20
2.00
2.00
4.00
4.00
4.00
4.00
4.00

28°C ≤ Ta
4.00
4.00
4.00
4.00

Construction and Experimental Analysis of the Device
The study utilized the 9 cm copper fin length and the magnitudes of variable intake air velocity inthe design of the AWG device. Figure 3 shows the blow-up figure of the AWG prototype.
The AWG device was continuously operated for 30 days in a secure open space located at
Manolo Fortich, Bukidnon for the experimental analysis. The testing area for the field test was
located in the backyard of a residential lot located in a rural community at Manolo Fortich,
Bukidnon. The period of testing was between September to October 2021 and the experimentalⒸ ISERD

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setup is shown in Fig. 3b. The average hourly RH, and the ambient air temperature were shown in
Fig. 4 and the average hourly water collection was shown in Fig. 5.

Fig. 3 Blow-up picture of the AWG Device with its corresponding parts (a)and finished product and experimental setup (b)Fig. 4 Average hourly ambient air temperature and relative humidity

Fig. 5 Average hourly water collection for the AWG device
It can be seen in Fig. 5 that the highest water collection rate of the AWG was during nighttime
since there were high RH levels paired with low surrounding temperatures. Overall, the highest
recorded amount of water collected in a day was 526 mL. Table 3 shows the comparison between
the outputs of this study compared to past literature.
Table 3 Comparison of water collected per day to past literatures
Researcher
Joshi et al. (2017)
Liu et al. (2017)
Present work

Location
India
China
PhilippinesⒸ ISERD

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Water collected (mL/day)
480
525
526

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CONCLUSION
The cold side fin length and air velocity are two important features of an AWG device that areneeded to be designed to improve the efficiency and water generation rate. The study observed thatwhile increasing the length of copper fins increases the cooling surface area, making the fin length
excessively longer does not positively impact the water generation rate of the AWG. Longer fin
lengths will develop dry regions along their length thus becoming inefficient.
Finally, the results of this study showed that there was an ideal air velocity at every climaticcondition to harness the maximum water generation rate for the AWG device. Low air velocities
were assigned to low surrounding temperature with low relative humidity conditions while high air
velocities were designated for high surrounding temperature and high relative humidity conditions.
The highest amount of water collected in a day was 526mL.
ACKNOWLEDGEMENTS
The author would like to acknowledge the Engineering Research and Development for Technology(ERDT) for funding this research and the Mindanao State University-Iligan Institute of Technology
for supporting this research.
REFERENCES
Hafner, S. 2018. Re: How much CO2/DIC dissolves in water vapor condensate under normal atmosphericconditions? Retrieved from https://www.researchgate.net/post/How-much-CO2-DIC-dissolves-in-watervapor-condensate-under-normal-atmospheric-conditions/5a75cecf615e27bab3589949/citation/download
Joshi, V., Joshi, S.V., Kothari, A.H., Mahajan, D.M., Chaudhari, B.M. and Sant, D.K. 2017. Experimental
investigations on a portable freshwater generator using a thermoelectric cooler. Energy Procedia, 109,
161-166, Retrieved from DOI http://doi: 10.1016/j.egypro.2017.03.085
Kilic, A. and Onat, K. 1981. The optimum shape for convecting rectangular fins when condensation occurs.
Warme - und Stoffubetragung, 15, 125-133, Retrieved from DOI https://doi.org/10.1007/BF01002408
Liu, S., He, W., Hu, D., Lv, S., Chen, D., Wu, X., Xu, F. and Li, S. 2017. Experimental analysis of a portable
atmospheric water generator by thermoelectric cooling method. Energy Procedia, 142, 1609-1614,
Retrieved from DOI https://doi.org/10.1016/j.egypro.2017.12.538
Rola, C.A., Pulhin, M.J., Tabios, Q.G., Lizada, C.J. and Dayo, F.M. 2015. Challenges of water governance in
the Philippines. Philippine Journal of Science, 144 (2), 197-208, Retrieved from https://philjournalsci.
dost.gov.ph/images/pdf/pjspdf/vol144no2/pdf/challenges_of_water_governance_in_the_Phils_FinalCopy_05_April_2016.pdf
Shourideh, H.A., Ajram, B.W., Lami, A.J., Haggag, S. and Mansouri, A. 2018. A comprehensive study of an
atmospheric water generator using peltier effect. Thermal Science and Engineering Progress, 6, 14-26,
Retrieved from DOI https://doi.org/10.1016/j.tsep.2018.02.015Ⓒ ISERD

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Research article
erd

DNA Fingerprinting of Selected Maize (Zea mays L.)
Genotypes using SSR Markers
SAN KYI*
Yezin Agricultural University, Nay Pyi Taw, Myanmar
Email: sankyi747@gmail.com

KYAW KYAW WIN
Pro-Rector’s Office of Administration, Yezin Agricultural University, Nay Pyi Taw, Myanmar

HLA THAN
Pro-Rector’s Office of Academic, Yezin Agricultural University, Nay Pyi Taw, Myanmar

SOE WIN
Department of Plant Breeding, Physiology and Ecology, Yezin Agricultural University,
Nay Pyi Taw, Myanmar

NYO MAR HTWE
Advanced Center for Agricultural Research and Education, Yezin Agricultural University,
Nay Pyi Taw, Myanmar

AYE LAE LAE HLAING
Plant Molecular Biology Laboratory, Biotechnology Research Section,
Department of Agricultural Research, Nay Pyi Taw, Myanmar
Received 28 January 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract Molecular marker has been used for variety identification, genetic diversity ofgenotypes and additional using intellectual property protection in DUS testing. DNA
fingerprinting of fourteen maize genotypes had been studied at Plant Biotechnology
Laboratory, DAR, Myanmar during 2020-2021. Nine hybrids and five inbreds wereanalyzed using 24 polymorphic SSR markers, resulted a total number of 101 alleles with arange from 2 to 9 alleles per locus. Polymorphism has been sufficiently detected with theaverage of 0.66 per SSR locus. Cluster analysis separated all the maize genotypes as five
major groups and indicated the existence of genetic variation among the observed inbreds
and hybrids. Six SSR primer pairs (dupssr12, bnlg1940, umc1248, umc1586, bnlg1518 andbnlg1028) were selected as final marker set for variety identification with the selection
criteria such as detection rate of the SSR fragment, the presence of rare allele, PIC value,
and reproducibility and PCR band pattern of SSR fragments. In this study, all tested
genotypes have been fingerprinted with unique profile identity (ID) to support the DNA
fingerprint catalogues of Myanmar Maize Molecular DUS test guidelines.
Keywords DNA fingerprinting, maize SSR markers, varietal identification

INTRODUCTION
Maize (Zea mays L.) is the most diverse crop species characterized at both morphological andmolecular levels (Anderson and Cutler, 1942; Buckler et al., 2006; Zheng et al., 2008). Genetic
identification of maize is essential in the process of crop improvement, crop quality estimation andthe finding of parent components and their crosses.
SSR markers were able to discriminate maize genotypes depending upon their hybridizationlevel and their genetic relationships among the different inbred lines (Kamal et al., 2010). It is themost powerful biotechnological tool, suitable for detecting of genetic purity status of maize hybrids.
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SSR also used in DNA fingerprinting analysis for identification of individuals, populations, inbredlines, and hybrids, making the description of the species at the molecular level, to protect thebreeders’ Rights and its protection.
Plant varietal protection and patents are the most important end products of plant breeding
institutes to get back their research investment by mean of intellectual property protection. DNA
fingerprinting technology is useful for preventing counterfeit and fake varieties in the market andthis fingerprinting information is additional information for DUS characterization (Wang et al.,2013). UPOV (2010) recommends SSRs for current construction of DNA fingerprint databases thathave been well-defined and tested. In the present study, the SSR primers set were used todifferentiate hybrids and inbreds, and to create the DNA fingerprint catalogues for supporting of
Myanmar Maize DUS test guidelines for identifying maize genotypes in infringement case, and for
utilizing as a source of parental line for future breeding programs.
METHODOLOGY
Plant Materials and Genomic DNA Extraction
Fourteen maize genotypes (Table 1) were used to study molecular characterization at Plant
Biotechnology Laboratory, Department of Agricultural Research (DAR), Myanmar during 20202021. Nine hybrids (imported by private companies) and five inbred lines (developed by DAR)
were used. Genomic DNA extraction, DNA quantification and qualification were carried out
according to the procedure of Hlaing et al. (2017).
Table 1 List of selected maize genotypes for molecular characterization
No.

Genotypes

Type

SourceNo.

Genotypes

Type

SourceV1

Asia Seed (A.55)

HybridChina

V8NK-621HybridSyngenta

V2

Asia Seed (A.99)

HybridChina

V9

TSF-1633

HybridThailandV3

AA-737HybridThailandV10

YZI-10-054

InbredDAR

V4GT-722HybridThailand

V11

YZI-10-095

InbredDAR

V5NK-625HybridSyngenta

V12

PAC-999

InbredThailand

V6

KMHE-3550

Hybrid

India

V13

C7

InbredDAR

V7

CP-111HybridThailandV14

YZCI-16-019

InbredDARPCR Amplification and Gel Electrophoresis
Twenty-four SSR primer pairs were used to identify the studied maize genotypes. These highly
polymorphic primer sets, PCR amplification and agarose gel electrophoresis were conductedfollowing the methods reported by previous research findings (Hlaing et al., 2017).
Statistical Analysis on Marker Data
The SSR allele segregation data were used to construct Nei distance dendrogram (Nei, 1972) using
NTSYSpc 2.1 software (Rohlf 2000). Polymorphism Information Content (PIC) for each SSR was
calculated by the formula PIC=1-ΣX2k/n developed by Ni et al. (2002) where, X2k represents thefrequency of the kth allele, and n represents the number of genotypes.
Development of Core SSR Marker Set for DNA Fingerprinting (DUS testing)Ⓒ ISERD

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Based on their specific discrimination capacity of SSR markers, the core marker set was developedwith the following criteria: (1) PCR banding pattern of SSR fragments (2) the presence of rare
allele (3) PIC values and (4) marker’s reproducibility. Furthermore, the genetic fingerprint map oftested maize genotypes was constructed using the coding-based system with the original allele size
coded by the assigned numeric values which set in two numeric codes from “01”, “02”, “03”, etc.
The transformation was generated to all cores SSR ID set based on allele size (bp) range. The final
SSR fingerprinting map of maize genotypes was produced to support variety identification and
DUS testing on PVP system.
RESULTS AND DISCUSSION
Amplification Profile, SSR Polymorphism and Cluster Analysis on Diversity Assessment
SSR markers have been proven to be powerful tools in the assessment of genetic variation within
and among the species. A total of 24 SSR primers were used for identification of maize genotypes
through evaluation of DNA fragment polymorphisms. A total number of 101 alleles were detectedwith a range from 2 to 9 alleles per locus. These varied number of alleles indicated that there is ahigh level of genetic diversity among tested genotypes. The primer pairs bnlg1028 showed thehighest number of 9 alleles per locus, umc1248 showed 8 alleles in all tested genotypes andumc1586, bnlg1940 and dupssr12 showed 6 alleles in all samples (Table 2).
Table 2 Data on number of alleles, total number of alleles, and PIC value
obtained among 14 maize genotypes for 24 SSR markers

1.

SSR
marker
umc1397

No. ofalleles4

Total no.
of alleles
20

PIC
value
0.63

13.

SSR
markerbnlg1617

No. ofalleles4

Total no.
of alleles
14

PIC
value
0.72

2.

umc2234

3

20

0.62

14.

umc1520

5

22

0.71

3.

dupssr12

6

30

0.77

15.

umc1248

8

38

0.85

4.

umc1542

3

5.

umc2372

4

20

0.62

16.

umc1393

3

15

0.66

19

0.70

17.

umc1671

5

24

0.59

6.

bnlg1940

6

28

0.74

18.

umc2395

3

16

0.53

7.
8.

bnlg1160

3

23

0.63

19.

bnlg1065

3

20

0.65

umc1501

4

16

0.73

20.

umc1586

6

48

0.80

9.

umc2061

4

16

0.72

21.

umc2359

2

14

0.41

10.

umc1101

3

19

0.61

22.

umc1962

5

34

0.77

11.

umc1752

2

14

0.50

23.

bnlg1518

4

18

0.67

12.

umc1792

2

15

0.48

24.

bnlg1028

9

36

0.78

No.

No.

The Polymorphism Information Content (PIC) value reflects the evidence of allele diversity
and allele frequency among the tested genotypes (Pervaiz et al., 2009). In present study, PIC value
ranged from 0.41 to 0.85 with an average value of 0.66 (Table 2). The highest PIC value wasobtained for umc1248 followed by umc1586, bnlg1028, dupssr12, umc1962, bnlg1940,
respectively. The PIC values of umc1248, umc1586, bnlg1028, dupssr12, and umc1962 werehigher than 0.75 that were considered as the best markers for studied genotypes.
The SSR markers with PIC value of 0.5 or higher indicate that these are highly informativeand extremely useful in distinguish the polymorphism rate of a marker at a specific locus(DeWoody et al., 1995). In this study, the genetic diversity of each SSR locus appeared to be
associated with number of alleles detected per locus, i.e. the higher the PIC value of a locus, thehigher the number of allele detected.
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Moreover, the amplification profile of the 14 maize genotypes using 24 SSR markers sets
showed alleles of different molecular weight, and displayed the higher polymorphism among thetested genotypes (Fig. 1). Our study highlighted the detection of genetic variability among thetested maize genotypes and also agreed the finding of polymorphic SSR markers by Liu and Muse(2005).
Cluster Analysis is a classification to determine whether the genotypes could be regarded asconsisting of a number of partially dissociated groups. Genetic dissimilarities obtained from SSR
marker data of 9 hybrids and 5 inbred maize genotypes were used to create a cluster diagram using
Nei’s genetic distance and the unweighted pair group method (UPGMA). Clustering analysis for 14
maize genotypes could be fully distinguished from one another and grouped into five major clusters(Fig. 2).

Fig. 1 Amplification of DNA profiles of the 14 maize inbreds and hybrids
generated by SSR primers(a) dupssr 12 (b) bnlg1940 (c) umc 1248 (d) umc 1586 (e) bnlg 1518 and bnlg 1028.
Lane M = 100bp DNA Ladder.
V1
V4
V2
V3
V5
V12
V14
V10
V6
V8
V7
V9
V10
V11
V13
0.29

0.44

0.60

0.75

0.91

CoefficientFig. 2 UPGMA clustering tree of 14 maize genotypes based on Nei’s genetic distance
Development of Core SSR Marker Set for DNA Fingerprinting (DUS testing)
The goal of development of core SSR marker set for genotype identification is to maximize
distinguishing ability of each marker with a minimum number of markers set in DNA
fingerprinting. In this study, the core marker candidate was decided with the selection criteria suchas detection rate of the SSR fragment, the presence of rare allele, PIC value, and reproducibility
and PCR band pattern of SSR fragments. As a result, six SSR primer pairs were selected as a final
marker set for variety identification, i.e., dupssr12, bnlg1940, umc1248, umc1586, bnlg1518 andbnlg1028 due to their characterization and discrimination capacity. These polymorphic markerⒸ ISERD

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pairs revealed that there were four to nine differentiated loci among all genotypes with a fragment
length of 50-57 bp to 600 bp across loci (Table 3).
Table 3 Coding system of selected six SSR marker set based on allele size (bp) range
Codedupssr12

bnlg1940

umc1248

umc1586

bnlg1518

bnlg1028

01

110-115

60-64

50-57

166-182

162

75

02

120-128

106-118

100

237

180

100

03

135-140

121-125

112-120282-310190-21311004

150-160

212-220125341-358

225-23813805

170-175

225-234150

400-415162

06

197-200

237-240

175-180

600

150

07

200-210

175-18708

230-232200

09

246-250

Table 4 SSR fingerprinting map of 14 maize genotypes based on their allele size codes
Genotype namedupssr12

bnlg1940

umc1248

umc1586

bnlg1518

bnlg1028

Asia Seed (A.55)

0204060205

050608

03

03

0103

Asia Seed (A.99)

03

0205

050608030506040104

AA-7370206

0205

05060801020405

04020409GT-7220206

0206

05060801030403020609NK-6250405060206

0102070102030405

03060709KMHE-3550

0203

0204

01020701030405

04060709CP-111

03

0205

0103

03040504060709NK-6210206

0204

01020401040503060809

TSF-1633

0206

0205

0102030102030405

04

0609

YZI-10-054

0106

0204

0104

01020304

020609

YZI-10-095

0103040204

0102040305060102

060709

PAC-9990205060103

0104

01030406

0304

0609

C7

0406

0102

010307

0304

03

0509

YZCI-16-019

0206

0103

0103

01030405

020304060709This allele size can be assigned as a specific DNA fingerprinting band of the genotypes andcan be used as the maize variety identification. The primer bnlg1028 was found the best marker for
the identification of studied genotypes as revealed by higher PIC values and showed the highest
polymorphism. In other study, DNA fingerprinting with SSR set of tested maize genotypes were
fully distinguished from one another compared to the specific SSR markers which differentiatedmaize hybrids from their parental inbreds (Jhansi et al., 2015). In this study, the genetic fingerprint
map of 14 maize genotypes was constructed using the coding-based method with the original allele
size coded by the assigned numeric values and the specific marker’s allelic fragments weretransformed into combine codes as final identity of the genotype, shown in Table 3 and Table 4. By
using the core marker set, the results of assigning numeric code or ID described a specific identityof the variety (genotype) that can quantitatively differentiate it from the others. In this study, 14maize varieties had unique profile ID to support plant variety protection and breeder right,
complementing tools for DUS testing purpose. It is noted that these findings not only met therequirements for the minimum number of primers but were also sufficient to fully distinguish the
14 varieties from one another.
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CONCLUSION
The goal of this research is to develop DNA fingerprinting catalogue of maize genotypes (bothinbreds and hybrids) using SSR polymorphic information and their genetic variance supporting
Myanmar maize DUS guidelines. In this study, the six pairs SSR sets generate the genetic
fingerprint map (coding system) of typical maize genotypes which can be used in DUS testing for
identification of hybrids and inbreds at any stage of crop growing cycle. Furthermore, molecular
based SSR testing provide a higher degree of detection efficiency in DUS testing than traditional
morphological based DUS method with regard to the verification of new varieties or genotypes.
ACKNOWLEDGEMENTS
The authors are grateful to the responsible persons from DOA, DAR and YAU for their kindpermission and collaborating to conduct this study. We acknowledge all the staffs of Biotechnology
Research Section, DAR for helping us.
REFERENCES
Anderson, E. and Cutler, C.H. 1942. Races of Zea mays: I. Their recognition and classification. Annals of theMissouri Botanical Garden, 29 (2), 69-88, Retrieved from DOI https://doi.org/10.2307/2394331
Buckler, S.E., Gaut, S.B. and McMullen, D.M. 2006. Molecular and functional diversity of maize. Current
Opinion in Plant Biology, 9 (2), 172-176, Retrieved from DOI https://doi.org/10.1016/j.pbi.2006.01.013
DeWoody, A.J., Honeycutt, L.R. and Skow, C.L. 1995. Microsatellite markers in white-tailed deer. Journalof Heredity, 86 (4), 317-319, Retrieved from DOI https://doi.org/10.1093/oxfordjournals.jhered.a111593
Hlaing, L.L.A., Sin, S.E., Chan, N.K., Tint, M.M.A., Yin, T., Yin, N.N. and OO, T.L. 2017. Molecularcharacterization of promising maize inbred lines using polymorphic microsatellite markers. Proceedingsof the First Agricultural Research Conference, Department of Agricultural Research, Yezin, Nay Pyi
Taw. 84-92.
International Union for the Protection of New Varieties of Plant (UPOV). 2010. Guidelines for
DNAprofiling: Molecular marker selection and database construction (“BMT guidelines”). UPOV,
Geneva, Switzerland.
Jhansi, G., Surender, M., Reddy, S.S.A. and Sunitha, B. 2015. DNA finger printing of maize hybrids anddevelopment of molecular ID’s using SSR markers. Research Journal of Agricultural Sciences, 6 (1), 4347.
Kamal, A., Reddy, S.K., Khan, A.N.M., Shetti, V.R., Ramaiah, J.M., Pushpavalli, N.S., Srinivas, C., PalBhadra, M., Chourasia, M., Sastry, N.G., Juvekar, A., Zingde, S. and Barkume, M. 2010. Synthesis,
DNA-binding ability and anticancer activity of benzothiazole/benzoxazole–pyrrolo [2, 1-c] [1, 4]
benzodiazepine conjugates. Bioorganic and Medicinal Chemistry, 18 (13), 4747-4761.
Liu, K. and Muse, V.S. 2005. Power marker: An integrated analysis environment for genetic marker analysis.
Bioinformatics, 21 (9), 2128-2129, Retrieved from DOI https://doi.org/10.1093/bioinformatics/bti282
Nei, M. 1972. Genetic distance between populations. American Naturalist, 106 (949), 283-292. Retrieved
from http://dx.doi.org/10.1086/282771
Ni, J., Colowit, M.P. and Mackill, J.D. 2002. Evaluation of genetic diversity in rice subspecies using
microsatellite markers. Crop Science, 42, 601-607, Retrieved from DOI https://doi.org/10.2135/cropsci2002.6010
Pervaiz, H.Z., Rabbani, A.M., Pearce, R.S. and Malik, A.S. 2009. Determination of genetic variability of
Asian rice (Oryza sativa L.) varieties using microsatellite markers. African Journal of Biotechnology, 8(21), 5641-5651, Retrieved from DOI 10.5897/AJB09.827
Rohlf, F.J. 2000. NTSYS-pc: Numerical taxonomy and multivariate analysis system version 2.1 exeter
publishing setauket. New York, USA.
Wang, Y.P., Shen, Q., Zhang, J., Li, H. and Wu, Y. 2013. Genetic diversity analysis and building of DNA
fingerprints of barley standard varieties in DUS testing based on SSR Markers. Journal of Triticeae
Crops, 2, 273-278.
Zheng, D., Van, K. and Lee, S. 2008. Molecular diversity and relationships among elite maize inbreds from
US and CIMMYT populations and current heterotic groups in China. Hereditas, 145 (4), 182-193,
Retrieved from DOI https://doi.org/10.1111/j.0018-0661.2008.02048.xⒸ ISERD

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Research article
erd

Toxicity of Plant Essential Oil from Khok Phutaka
Resources Protection Area, Khon Kaen Province Against
Storage Pest, Sitophilus oryzae
DUANGRAT THONGPHAK*
Entomology Section, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
E-mail: duathg@kku.ac.th

PRAPAPORN PIANGSUWAN
Entomology Section, Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
Received 30 January 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract Botanical insecticides may offer an alternative solution for pest control. The
objective was to test on the repellant, contact, and fumigant effect of the essential oils of 10
indigenous plants from Khok Phutaka Resources Protection Area, Khon Kaen Province
including Limnophila aromatica, Piper sarmentosum, Clausena harmandiana,
Streptocaulon juventas, Litsea glutinosa, Thunbergia laurifolia, Eupatorium odoratum,
Rothmannia wittii, Ficus altissima, Clausena harmandiana and Gymnopetalum integrifolim
to control the rice weevil, S. oryzae. The essential oils of plants were extracted by usinghydro-distillation method and then they were tested against rice grain weevil, S. oryzae forcontact, fumigant and repellent activities in laboratory condition. Adults of weevil weredifferent tested oil at the concentrations of 0, 25, 50, 75 and 100 percentage (w/v). The
maximum repellency action, 80% when L. glutinosa oil, at the concentrations of 100%(w/v) were applied for after 72 hours follow by L. aromatica (73.33%) at the concentrationsof 25% (w/v) were applied for after 2 hours. The fumigant and contact test of all 10
essential oils resulted in all lower rate mortality (less than 50%), at all the concentrations.
Keywords essential oil, Sitophilus oryzae, repellency, fumigant, contact,
Khok Phutaka Resources Protection Area

INTRODUCTION
The rice weevil, Sitophilus oryzae Linnaeus 1763 (Coleoptera: Curculionidae) is a serious andsevere insect pest of stored products (Park, 2003) and one of the most widespread and destructive
stored product pests of rice throughout the world. Treatment of rice with synthetic insecticides is
not recommended because of direct and indirect health hazards to humans. Plants are sources ofnatural insecticides that are produced to defend themselves against those insect pests. Many plants
are rich in secondary compounds with insecticidal activities. The several efforts have been focusedon the use of plant derived materials including essential oils as bio insecticides.
OBJECTIVE
The objective of this study was to screen plant oils of 10 indigenous plants from Khok Phutaka
Resources Protection Area, Khon Kaen Province as repellent contact and fumigant against adults ofrice weevil, S. oryzae.
METHODOLOGY
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Adults of S. oryzae were reared in the laboratory conditions at 25 ± 2ºC, 46.8 ± 5.0% R.H.
Approximately, 50 of S. oryzae adults were placed in 11×10×5 cm plastic containing 500 g of ricegrains. Colonies were reared on whole rice grains in plastic container. The insects were reared forseveral generations on rice. For the bioassays, the F1 generation of the adults from the rearing wasused.
Extraction of Essential Oil
Ten of indigenous plants were collected from Khok Phutaka Resources Protection Area, Khon
Kaen Province (Table 1). The essential oils of plants were extracted by using hydro-distillation
method.
Table 1 Plant essential oils used in the study
Scientific Name
Litsea glutinosa
Thunbergia laurifolia
Streptocaulon juventas Merr
Ficus altissima
Eupatorium odoratum L.
Rothmannia wittii
Clausena harmandiana
Gymnopetalum integrifolim Kurz.
Limnophila aromatica (Lam.) Merr.
Piper sarmentosum Roxb.

FamilyLauraceae
Acanthaceae
Asclepiadaceae
Moraceae
Asteraceae
Rubiaceae
Rutaceae
Cucurbitaceae
Plantaginaceae
Piperaceae

Plant used
LeavesLeavesLeavesLeavesLeavesLeavesLeavesLeavesWhole plant
LeavesRepellent Activity Bioassay
The repellency test was used the area preference method based on Lü and Ma (2015). The essential
oils of plants were diluted in acetone to prepare different concentrations (25, 50, 75 and 100%(w/v)). Pure acetone was used as the control. Each treatment was replicated five times. The numberof insects present on the control and treated regions were recorded to 1, 2, 3, 4, 5, 6, 12 and 24
hours after treatment. Mean number of insects present on the control (NC) and treated (NT) regions
during the experiment were used to estimate the Percent Repellency (PR) which was equal to[NC/(NC+NT)] × 100 (Nerio et al., 2009).
Contact Toxicity Bioassay
The contact toxicity test was done by the used of impregnated filter paper test method modified
from Fournet et al. (1996). The essential oils of the plants were diluted in acetone to prepare four
different concentrations (25, 50, 75 and 100% (w/v)). Controls were treated with acetone alone.
Ten adults of S. Oryzae were released separately into each petri dish and covered with a lid. Fivereplicates of each treatment and control were set up. Mortality was recorded after 24, 48, and 72
hours. Mortality rate was estimated and corrected according to Abott’s formula (Abbott, 1925)
Fumigant Toxicity Bioassay
The fumigant toxicity test was conducted by using space trial test method based on Keita et al.
(2001). Series of dilutions of essential oils were prepared different concentrations (25, 50, 75 and100% (w/v)) using acetone as a solvent. Five replications of each treatment were set up. Controls
were maintained in the similar way with the solvent only. Mortality was recorded after 24, 48, and72 hours. Mortality rate was estimated and corrected according to Abott’s formula (Abbott, 1925).
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RESULT AND DISCUSSION
Ten different plant oils were tested against the adults of Sitophilus oryzae at concentrations of 25,
50, 75 and 100% (w/v) for repellent activity, contact toxicity and fumigant toxicity tests.
Repellent Activity Bioassay
In general, repellency increases with increase in concentration in the treatment. The result indicatedvariation among the essential oils tested. The Percent Repellency (PR) ranged from 23.33 to
80.00%. The maximum repellency action, 80% when L. glutinosa oil, at the concentrations of
100% (w/v) were applied for after 72 hours follow by L. aromatica (73.33%) at the concentrationsof 25% (w/v) were applied for after 2 hours (Fig. 1). Arshad et al. (2013) that tested the repellentsof guava leaf extracts found 20% (w/v) concentration of P. guajava was the one with the highest
repellent effects on S. oryzae with mean % repellent of 70.3% (class 4) might be attributed topresence of some aromatic monoterpenoids that are major constituents of family Mytaceae (Isman,2000) and this substance is a group of substances found in L. aromatica as well (Vairappan andNagappan, 2014).

Fig. 1 Comparison percent repellency (PR) of the 10 essential oils
with different concentration to Sitophilus oryzae adults
after exposure time using the area preference method
Contact Toxicity Bioassay
Mortality of S. oryzae varied from 0 to 30% after 24, 48, 72 hrs. of treated of 10 essential oils ofplants at 25, 50, 75 and 100 concentrations (w/v). These results demonstrate (Fig. 2) that theefficiency of the oils was directly related to concentration and exposure time. Oil from R. wittii was
the most efficient, causing 30% mortality at concentrations of 100% (w/v) in 72 h. The result
indicated that all concentrations are lower rate mortality. Some other studies have found different
result from this study such as Mattana et al. (2018) showed that the essential oil of P. sarmentosum
leaves showed strong contact and fumigant toxicity at 72 h against adults of S. oryzae. Differences
may be due to the collect from different seasons of the year, soil type and climate, among others
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The result of fumigant toxicity (Fig. 3) showed that adult rice weevil exposure to the 10 essential
oil of plant different concentration had lower effect on mortality (less than 50%) except the oilfrom T. laurifolia was the most efficient, causing 56% mortality at 100% (w/v) concentration in 72
hr. Fumigant toxicity of the essential oils gradually increased with increasing exposure time andconcentration. Fang et al. (2010) reported that the essential oil of Carum carvi L. fruit was
insecticidal activity against the maize weevil and red flour beetle adults. Mishra et al. (2012)
reported that the essential oils of Syzygium aromaticum and Aegle marmelos have fumigation
toxicity against S. oryzae at 48 hours exposure were the LC50 values 15.3 and 16.1 µl respectively.

Fig. 2 Comparison contact effect of plant extracts with different concentration
to S. oryzae adults after exposure time using impregnated filter paper test

Fig. 3 Fumigant effect of plant extracts with different concentration
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CONCLUSION
The results obtained in this study demonstrate that the essential oils tested can be used to control
stored grain pests and to support further studies. The toxic effects of essential oils involve manyfactors, among which are the entry point of toxins, and which may have contact, fumigation, andrepellent effects. However, in the present study some of the plant oils did not show any mortality or
showed least mortality which might be due to the presence of weak volatile compounds. However,
the results of this study indicate that the essential oils might be useful for managing the insect pests
in storage especially S. oryzae.
ACKNOWLEDGEMENTS
This research was supported by the Program Management Unit for Human Resources &Institutional Development, Research and Innovation [grant number B05F630053] and the research
was a part of the Plant Genetic Project under The Royal Initiative of Her Royal Highness Princess
Maha Chakri Sirindhorn, Khon Kaen University [grant number 630000050102].
REFERENCES
Abbott, W.S. 1925. A method of computing the effectiveness insecticides. Journal Economic Entomology, 18(2), 265-267.
Akhtar, M., Arshad, M., Raza, M.B.A., Chaudhary, I.M., Iram, N., Akhtar, N. and Mahmood, T. 2013.
Repellent effects of certain plant extracts against rice weevil, Sitophilus oryzae L. (ColeopteraP;
Curculionidae). International Journal of Applied Agricultural Research. 5 (1), 69-73.
Fang, R., Jiang, H.C., Wang, Y.X., Zhang, M.H., Liu, L.Z., Zhou, L., Du, S.S. and Deng, W.Z. 2010.
Insecticidal activity of essential oil of Carum carvi fruits from China and its main components against
two grain storage insects. Molecules, 15, 9391-9402.
Fournet, A., Arias, R.A. de, Charles, B. and Bruneton, J. 1996. Chemical constituents of essential oils ofmuña, Bolivian plants traditionally used as pesticides, and their insecticidal properties against Chagas'
disease vectors. Journal of Ethnophar Macology, 52, 145-149.
Isman, B.M. 2000. Plant essential oils for pest and disease management. Crop Protection. 19, 603- 608.
Keita, M.S., Vincent, C., Schmit, J.P., Arnason, T.J. and Belanger, A. 2001. Effecacy of oil of Ocimum
basilicum L. and O. gratissimum L. applied as an insecticidal fumigant and powder to control
Callosobruchus maculates (Fab.) (Coleoptera: Bruchidae). Journal of Stored Products Research. 37, 339349.
Lü, J. and Ma, D. 2015. Repellent and contact toxicity of alpinia officinarum rhizome extract against
lasioderma serricorne adults. PLoS ONE, 10 (8), e0135631.
Mattana, K., Vanichpakorn, Y. and Vanichpakorn, P. 2018. Chemical composition and toxicity of essential
oil from Piper sarmentosum leaves against Sitophilus oryzae. Khon Kaen Agriculture Journal, 46
Supplement, 1, 189-194.
Mishra, B.B., Tripathi, P.S. and Tripathi, M.P.C. 2012. Bioactivity of two plant derived essential oils against
the rice weevils Sitophilus oryzae (L.) (Coleoptera: Curculionidae). Proceedings of the National
Academy of Sciences India Section B - Biological Sciences, 83 (2).
Nerio, S.L., Olivero-Verbel, J. and Stashenko, E.E. 2009. Repellency activity of essential oils from sevenaromatic plants grown in Colombia against Sitophilus zeamais Motschulsky (Coleoptera). Journal of
Stored Products Research, 45, 212-214.
Park, I.K., Lee, S.G., Choi, D.H., Park, J.D. and Ahn, Y.J. 2003. Insecticidal activities of constituents
identified in the essential oil from leaves of Chamaecyparis obtusa against Callosobruchus chinensis (L.)
and Sitophilus oryzae (L.). Journal of Stored Products Research, 39 (4), 375-384.
Vairappan, S.C. and Nagappan, T. 2014. Major volatile hydrocarbons of rice paddy herb, Limnophila
aromatica Lam. Merr as possible chemotaxonomic marker. Journal of Tropical Biology andConservation, 11, 41-48.

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Research article
erd

Microbial Behavior in Cambodian Homemade-style Pickles
SHUKI MURAMATSU*
Faculty of Health and Food Sciences, Showa Women’s University, Tokyo, Japan
Email: s-muramatsu@swu.ac.jp

SOKLY SORM
Graduate School of Agriculture, Tokyo University of Agriculture, Tokyo, Japan

MASATAKA UCHINO
Faculty of Life Sciences, Tokyo University of Agriculture, Tokyo, Japan

MOTOE SEKIDO
Department of Food and Nutrition, Yamanashi Gakuin Junior College, Tokyo, JapanYOSHIKI MURAMATSU
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanDAIKI OKA
Faculty of Applied Biosciences, Tokyo University of Agriculture, Tokyo, JapanYURI TANIOKA
Faculty of International Agriculture and Food Studies, Tokyo University of Agriculture, Tokyo,
Japan

TAKAHIKO NAKAMURA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanTORU NAKAJIMA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, JapanMARI ARIMITSU
Extension Center, Institute of Environmental Rehabilitation and Conservation, Tokyo, Japan

MACHITO MIHARA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan
Received 26 January 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract Pickled products made using vegetables are popular in Cambodia. Many types ofhomemade pickles are sold at wet markets. Our previous study showed that pickles areseriously contaminated by microbes, including food poisoning bacteria. Such contamination
may depend on several factors. The objectives of this study were to investigate the levels ofcontaminating microbes and their growth patterns in pickles prepared according totraditional Cambodian recipes and to suggest an improved method to ensure the microbialsafety of homemade pickles. Three kinds of pickles, namely cucumber pickles with orwithout fish sauce and bok choy pickles, were prepared following the methods used by
local people. Five sample bottles for each kind of pickle were prepared to observe changes
in their characteristics over time. The Brix values, salt concentrations, and pH of thesamples were measured. Next, we conducted microbiological examination of the samples
by testing the presence of total viable bacteria, coliforms, and fungi. More than 5.00 log10
CFU/g of total bacteria were detected in all pickle samples at day 0; moreover, the numberof bacteria increased until day 4. A similar concentration of coliforms was observed. Somesamples tested positive for fungi. In conclusion, all samples were contaminated by harmfulⒸ ISERD

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microorganisms that may cause food spoilage. The results of this study revealed thatmicrobial growth occurred in all tested pickles, resulting in a high risk of food spoilage andfood poisoning. We suggest that an additional step of pasteurization would help provide
microbiologically safe products. Moreover, use of food additives that do not alter the tasteof pickles may allow maintenance of low levels of microorganisms.
Keywords pickles, microorganisms, contamination, microbial quality

INTRODUCTION
Pickled products made using vegetables are popular in Cambodia. Many types of homemade
pickles are sold at wet markets. In our previous study, we showed that pickles are seriously
contaminated by microbes, including food poisoning bacteria (Muramatsu, 2020a, b). Despite theseriousness of this issue for local people in Cambodia, there are few reports on the food safety ofhomemade products. In particular, lack of surveys on food poisoning cases in the local population
makes it hard to grasp the current state of food safety in Cambodia.
Food safety is a pivotal issue for all countries. Indeed, food safety and/or food sanitation isindispensable for human quality of life and promotes not only good health but also economic
growth (Fung, 2018). Nevertheless, the World Health Organization (WHO) reported approximately
600 million cases of foodborne illness and more than 400,000 cases of death from foodborne illness
in 2010 (WHO, 2015). Foodborne illness is a serious threat in both developing and developed
countries. Most outbreaks of illnesses associated with food consumed at home have been underdiagnosed and/or under-reported (Redmond and Griffith, 2003; Keegan, 2009; Vrbova, 2012). In
particular, it is estimated that less than 1% of such cases are reported in developing countries(Satcher, 2000). Especially in developing country, food poisoning incidents are underestimated(Bhaskaran et al., 2020; Rusnan et al., 2020; Le et al., 2021). Thus, investigating only food poisoning
incidents that have been reported is not sufficient to ensure public health.
Contamination of homemade-style pickles may have several causes. For instance, microbial
behavior during the preparation of pickled products is plausibly associated with food contamination.
Therefore, in this study, we focused on microbial quality of homemade pickles and highlight
existing issues in cooking methods and types of ingredients and seasoning used for their
preparation.
In this study, three kinds of pickles, namely cucumber pickles with and without fish sauce, andbok choy pickles were prepared following the methods used by local people. The samples preparedin this study showed a highly risk to food poisoning. We aimed to investigate the microbiologicalquality of homemade pickles and suggest an improved method to obtain safe homemade products.
OBJECTIVE
The objectives of this study were 1) to determine the microbial quality and nutritional properties ofhomemade-style pickles, and 2) to suggest an improved method to obtain safe homemade products.
METHODOLOGY
Materials and Pickle Production Process
Three kinds of pickles were prepared according to recipes used by local Cambodians. The
ingredients and seasonings of the pickles are shown in Table 1. Sugar, salt, soy sauce, and fishsauce were purchased in Cambodia and used for seasoning. The other materials used werepurchased in Japan. Bok choy was used instead of mustard because of unavailability of the latter.
Bok choy belongs to the Brassica genus similar to mustard. Cucumbers were washed with tap
water and pat dried with a paper towel. The cucumbers used for sample A were rubbed with salt,
compressed using a weight, and left to stand for 60 minutes. Then, the salt on the surface of theⒸ ISERD

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cucumbers was wiped off with a paper towel. The cucumbers were cut to fit into a glass bottle andused until the stem end and the tip. For bok choy, the end of each bunch was first cut off, andleaves were separated from the stalks. The leaves were then washed with tap water and pat dried
with a paper towel. Garlic and a small onion were peeled and sliced. A piece of chili was sliced
into rings. After placing the mixed ingredients and liquid seasoning into glass bottles, these were
kept at 30°C for 4 days until the products were ready (Fig. 1). Since the original homemade-styleprocess includes keeping the mixture under the sun for 4 days, in this study, the pickles were kept
at 30°C under conditions close to those of the traditional method. Five samples for each kind of
pickle were prepared in order to observe changes in their characteristics over time. A mixed sample
was kept at 30°C for 30 minutes and used as the sample at day 0. Another sample was kept at 30°C
for 20-24 hours and considered the sample at day 1, and samples at days 2-4 were prepared in asimilar manner. The samples were stored at 4°C for subsequent analysis.
Table 1 Ingredients and seasonings used in the three kinds of pickles
Sample A
Cucumber withfish sauce
500
80.0
70.0
48.0
48.0
300
15
5
1

Ingredients andseasonings
Cucumber (g)Bok choy (g)Steamed rice (g)Sugar (g)Salt (g)Soy sauce (mL)Fish sauce (mL)
Hot water (mL)
Water (mL)
Garlic (g)Small onion (g)Chili (piece)

Sample B
Cucumber without
fish sauce
500
17.5
400
18.75
1

Sample C
Bok choy
500
18.0
6.0
16.0
400
-

Fig. 1 Appearance of pickles at day 0 and day 4(a) sample; cucumber with fish sauce, (b) sample B; cucumber without fish sauce,and (c) sample C; bok choy

Measurement of Food Properties
Since the sugar and salt contents and pH of foods affect microbial growth, their values can be good
indicators of the preservability of food. Therefore, we measured the Brix sugar content (soluble
solids content), salt content, and pH of the pickled liquid of the samples using a Brix refractometer(Atago, Tokyo, Japan), a salt meter (Horiba, Kyoto, Japan), and a pH meter (Horiba), respectively,
for all prepared samples.
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After collecting all samples, several microbial detection assays were performed. Ten grams of eachsample containing pickled ingredients and seasoning liquid was mixed with 90 mL of Maximum
Recovery Diluent (Merck KGaA, Darmstadt, Germany) solution in a sterilized storage bag. To
obtain homogeneous suspensions, samples were homogenized using a Stomacher blender. After
stomaching, 1 mL of sample suspension was mixed with 9 mL of Maximum Recovery Diluent
solution in a sterile tube. A series of diluted samples was used for the detection of total viablebacteria, coliforms, and fungi. Standard agar medium (AS ONE, Osaka, Japan) was used for thedetection of total viable bacteria. Desoxycholate agar medium (AS ONE) was used for thedetection of coliforms. Solid plates were incubated at 35 ℃ for 48 hours. For the detection of fungi,
plates with Potato Dextrose Agar medium (AS ONE) were incubated at 30 ℃ for 5 days.
RESULTS AND DISCUSSION
Nutritional Properties of Pickles Prepared According Traditional Recipes
The nutritional properties of the final pickled products are shown in Table 2. Sample A showed thehighest Brix value and salt concentration. The measured pH values varied slightly among replicates.
The pH value could be affected by the microbes present in the samples; therefore, differences in theidentity of contaminating microorganisms would result in variations in pH.
Table 2 Nutritional properties of final pickled products
Measured
item
Brix
pH
Salt (%)

Sample A
Cucumber withfish sauce
11.2
4.55
5.1

Sample B
Cucumberwithout fish sauce
4.4
4.5
2.3

Sample C
Bok choy
4.7
4.88
2.4

Fig. 2 Changes in chemical properties of the three kinds of pickles(a) salt concentration and (b) pH
The Brix values of all pickles did not change much from day 0, just after pickling, to day 4,
and were approximately constant (data not shown). The lack of decreasing Brix values indicatesthat the microorganisms in samples A and C were unlikely to utilize sugar. During the 4-day
storage period, the salt concentrations in samples B (cucumber without fish sauce) and C (bokchoy) decreased slightly, whereas that in sample A (cucumber with fish sauce) remained almost
constant (Fig. 2(a)). All samples first displayed pH values of approximately 6, but these gradually
decreased over time (Fig. 2(b)). Decreasing pH values indicated that the microbes in the samples
produced acids. Clostridium botulinum, which can trigger deadly diseases, can grow at a minimum
pH of 4.6. Improper home canning of vegetables and improperly fermented and processed foods
have caused outbreaks in many countries (Matthews, 2017). In particular, pickles in sealedcontainers with pH higher than 4.6 seem to have considerable potential to cause severe foodpoisoning. Moreover, the Brix value and salt concentration of pickles are presumably not sufficientⒸ ISERD

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to inhibit the growth of most bacteria and yeasts; therefore, molds grow regularly in pickles(Matthews, 2017).
Microbial Behavior in Homemade Pickles
A total of five samples (from day 0 to day 4) for each of the three kinds of pickles were used toobserve changes in microbial composition over time. We tested the presence of total viable bacteria,
coliforms, and fungi (Fig. 3). More than 5.00 log10 CFU/g of total bacteria were detected in all
pickle samples at day 0; also, the number of bacteria increased until day 4 (Fig. 3(a)). Coliforms
were detected at a level similar to that of total viable bacteria. The initial number of coliforms insamples B and C was almost 5.00 log10, and sample A also tested positive for these bacteria. The
concentration of coliforms increased until day 4 (Fig. 3(b)). Coliforms are considered indicators of
fecal contamination; however, they have been recently acknowledged to be able to grow in nonfecal sites such as food, water, and waste (Matthews, 2017). Therefore, contamination by coliforms,
as shown in Fig. 3(b), does not directly imply insanitary conditions. Izumi (2010) reported thatvegetables dipped in tap water showed a total bacterial count of approximately 5 log10. Thissuggests that only washing vegetables with tap water does not eliminate harmful microorganisms.

Fig. 3 Changes in the number of microbes in the three kinds of pickles(a) total viable bacteria, (b) coliforms, and (c) fungiColony observation on agar plates revealed that many samples were contaminated bydangerous microorganisms that could cause food spoilage. Thus, none of the prepared pickles were
safe to eat. Fungi were not detected on day 0 in sample A, and some samples tested negative or
positive for fungi on days 1-4. Conversely, samples B and C showed fungal contamination on days
0, 1, and 4. We believe that continuous growth was not observed because each sample formicrobial counting was placed in an independent bottle in order to prevent contamination of thesample once opened for analysis. The microflora of vegetables is generally composed by 80%
bacteria and 20% fungi (Izumi, 2008). This observation suggests that bacteria remained in all
samples prepared by washing with tap water, but fungi were eliminated from some samples. The
results of this study suggest that microbial growth occurred in all three kinds of pickles, resulting ina high risk of food spoilage and food poisoning. Therefore, the current production process needs tobe modified to improve microbial quality. The addition of a pasteurization step and/or the use ofⒸ ISERD

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food additives is an effective and practicable solution. Similar cucumber pickles containing asimilar amount of salt, after storage at 30°C for 2 days, were reported to carry 8 log10 CFU/g oftotal viable bacteria and maintain this initial concentration for 8 days at 4°C (Miyao, 2004).
Moreover, some trials of pickle production showed that the products were of uneven quality. Thisimplies that the traditional methods and ingredients used in this study do not allow spontaneousdesirable fermentation into safe products.
In this study, pickles were prepared following homemade-style recipes and analyzed for theirmicrobial quality. We suggest that pasteurization is required to obtain microbiologically safe
products. Moreover, the use of food additives such as glycine, which does not alter the taste ofpickles, sorbic acid, or alcohol during preparation seems to be effective in controlling theconcentration of microorganisms.
CONCLUSION
In this study, three kinds of pickles were prepared following local traditional methods. To observechanges over time, five pickle samples were prepared for days 0 to 4. The Brix value, salt
concentration, and pH of the pickling liquids were measured, and microbial detection assays were
performed. More than 5.00 log10 CFU/g of total bacteria was detected in all the samples at day 0;
also, the number of bacteria increased until day 4. Coliforms showed concentrations similar to
those of total viable bacteria. Some samples were positive for fungi. In conclusion, all samples
were contaminated by harmful microorganisms that could cause food spoilage.
The results of this study revealed that microbial growth occurs in all pickles, posing high risk
to food spoilage and food poisoning. We suggest that pasteurization would help obtainmicrobiologically safe products. Moreover, use of food additives that do not alter the taste ofpickles may allow maintenance of low levels of microorganisms.
REFERENCES
Fung, F., Wang, H. and Menon, S. 2018. Food safety in the 21st century. Biomedical Journal, 41 (2), 88-95,
Retrieved from DOI https://doi.org/10.1016/j.bj.2018.03.003
Izumi, H. 2008. Studies on microbiological safety of fresh-whole and fresh-cut produce. Food Preservation
Science, 34 (2), 85-95, Retrieved from DOI https://doi.org/10.5891/jafps.34.85
Izumi, H. 2010. Microbiological safety of fresh produce from the farm-to-table food chain. Memoirs of the
School of BOST of Kinki University, 26, 3-11.
Keegan, A.V., Majowicz, E.S., Pearl, L.D., Marshall, J.B, Sittler, N., Knowles, L. and Wilson, B.J. 2009.
Epidemiology of enteric disease in C-EnterNet’s pilot site, Waterloo region, Ontario, 1990 to 2004.
Canadian Journal of Infectious Disease and Medical Microbiology, 20, 79-87, Retrieved from DOI
https://doi.org/10.1155/2009/978784
Le, T.H.H., Dalsgaard, A., Andersen, S.P., Nguyen, M.H., Ta, T.Y. and Nguyen, T.T. 2021. Large-scale
Staphylococcus aureus foodborne disease poisoning outbreak among primary school children.
Microbiology Research, 12, 43-52, Retrieved from DOI https://doi.org/10.3390/microbiolres12010005
Matthews, R.K., Knile, E.K. and Montville, J.T. 2017. Food microbiology (4th ed.). American Society for
Microbiology, ASM Press, ISBN 978-1-555-81938-5, USA.
Miyao, S. 2004. Synthetic control of the microorganisms in quality stabilization of pickles. Food
Preservation Science, 30, 29-38, Retrieved from DOI https://doi.org/10.5891/jafps.30.29
Muramatsu, S., Uchino, M., Tanioka, Y., Sorm, S., Oka, D., Muramatsu, Y., Nakajima, T., Sekido, M.,
Nakamura, T., Chay, C. and Mihara, M. 2020a. Evaluation of bacterial contamination levels in pickles
sold at wet market in Cambodia, Part 1, In case of samples from Kampong Cham and Phnom Penh.
International Journal of Environmental and Rural Development, 11 (1), 115-120, Retrieved from DOI
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Muramatsu, S., Uchino, M., Sorm, S., Tanioka, Y., Oka, D., Muramatsu, Y., Nakajima, T., Sekido, M.,
Nakamura, T., Chay, C. and Mihara, M. 2020b. Evaluation of bacterial contamination levels in pickles
sold at wet market in Cambodia, Part 2, Detection of several food-poisoning bacteria of 48 samples from
Phnom Penh. International Journal of Environmental and Rural Development, 11 (1), 121-126, Retrieved
from DOI https://doi.org/10.32115/ijerd.11.1_121
Redmond, C.E. and Griffith, J.C. 2003. Consumer food handling in the home: A review of food safetyⒸ ISERD

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studies. Journal of Food Protection, 66 (1), 130-161, Retrieved from DOI https://doi.org/10.4315/0362028X-66.1.130
Rusnan, N.A., Nordin, N., Radu, S. and Abdul-Mutalib, N.A. 2020. Pathogenic Bacillus cereus, An
overlooked food contaminants in Southeast Asia. Tropical Agricultural Science, 43 (1), 1-7.
Satcher, D. 2000. Food safety: A growing global health problem. Journal of American Medical Association,
283 (14), 1817, Retrieved from DOI https://doi.org/10.1001/jama.283.14.1817
Sunil, B., Maya, S., Irshad, A. and Sunikumar, N.S. 2020. Zoonoses recent approaches to contain the global
zoonotic burden. Indian Veterinary Association, Kerala, College of Veterinary and Animal Sciences,
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Vrbova, L., Johnson, K., Whitfield, Y. and Middleton, D. 2012. A descriptive study of reportable
gastrointestinal illnesses in Ontario, Canada, from 2007 to 2009. BMC Public Health, 12 (970),
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World Health Organization (WHO). 2015. WHO estimates of the global burden of foodborne diseases:
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Research article
erd

Impact Analysis of Population Growth and Fertilizer Use on
Nitrogen Runoff in Nam Ngum Basin, Laos
KOSHI YOSHIDA*
Graduate School of Frontier Sciences, The University of Tokyo, Chiba, Japan
Email: kyoshida@edu.k.u-tokyo.ac.jp

ISSAKU AZECHI
Graduate School of Bioresources, Mie University, Mie, JapanTOSHIAKI IIDA
Faculty of Agriculture, Iwate University, Iwate, Japan
Received 29 January 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract Human population growth has led to increased energy and food production,
fertilizer usage and wastewater flows. Increased nitrogen availability is a worldwide causeof eutrophication of rivers, lakes and estuaries, however, quantitative evaluation the impactsof nitrogen loads has been insufficient in developing countries because of poor data
availability. The Nam Ngum River basin, Laos, which supplies quality water for domestic
use in the Vientiane Metropolis, was selected as the target area for this study. The Nam
Ngum River basin is 415 km long with a 17,000 km2 catchment area, and the main land
uses in 2000 were paddy (15.6%), forest (32.3%), shrub (40.3%) and urban (0.2%). By UN
estimation, population in Laos is expected to increase 2.1 times from 2000 to 2050, andfertilizer use also will increase to produce sufficient food. Therefore, future water quality isa main concern in this river basin. Meteorological and hydrological data from 1995 to 2004,
and spatial data such as topography, land use, and soil properties were collected for model
simulation. A conceptual nitrogen balance model with three nitrogen pools was developed
and combined with a rainfall runoff model. Simulated river discharge and nitrogen loads
agreed with the observed data. Then, we investigated future nitrogen load variations in thebasin under different population growth and agricultural modernization scenarios. As aresult, even when population in the basin increased 2.1 times, nitrogen load did not change
significantly (11,676 tons/year in 2000 and 11,822 tons/year in 2050). However, thefertilizer increase scenario, from 25 kg/ha/season to 50 kg/ha/season, showed significant
increase in nitrogen loading, from 11,676 ton/year to 17,010 ton/year. Our results provide
initial insight into the magnitude and spatial distribution of nitrogen loading in Nam Ngum
River Basin, showing that this type of model may be useful for future impact assessments.
Keywords nitrogen load, point sources, diffuse pollution, agricultural modernization

INTRODUCTION
As the population increases, especially in developing countries, there is a need to increase foodproduction. This can be achieved in two ways: by expanding farmland and by increasing the yield
per unit area. The area of agricultural land in the world has already begun to decrease due to soil
degradation and other reasons, thus it is difficult to expect a significant increase in the area ofagricultural land. Therefore, the most realistic approach is to increase the yield per unit area (i.e.
increase the number of crops planted per year by switching to high-yielding varieties andintroducing irrigation systems). The introduction of high-yielding varieties, known as the Green
Revolution, has increased agricultural productivity, but chemical fertilizer inputs and advanced
management of agricultural water (irrigation and drainage) have become prerequisites forcultivation of such crops. As a result, pollution in closed water bodies in Asia has become aproblem due to excessive nutrient runoff caused by rapid population increase and the massiveⒸ ISERD

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application of chemical fertilizers. The water quality problem is particularly serious in the rapidly
developing tropical Asian monsoon region, where more than 30% of the world's chemicalfertilizers are applied. Because the population is still increasing, and it is necessary to develop
infrastructure to achieve stable food production and water environmental conservation (Tanaka etal., 2013). Normally, water quality is observed at the mainstream only, limiting understanding of
the spatial distribution of nutrient runoff from monitoring surveys alone. Additionally, it is difficult
to understand the spatial and temporal distribution of water resources and nutrient loading indeveloping countries due to low observation density and lack of observation data at the tributarylevel. A variety of methods have been used to model nitrogen transfer in river basins. Conceptualand physically based models (Lee et al., 2006; Conan et al., 2003; Whitehead et al., 2006) describe
the processes responsible for nitrogen wash-off into surface water and leaching to groundwater inlarge heterogeneous basins. Such models allow forecasting and a better understanding of processes.
However, even if these facts are well known, few scientific works on water quality in developing
countries have been published until recently, because available data are quite limited in suchregions. In this study, a water cycle and nitrogen dynamics model, which considered the local
cultivation and water treatment system, was developed and applied to a tropical Asian monsoon
basin with a paddy rice culture similar to that of Japan.
METHODOLOGY
Study Area
The Nam Ngum River basin in Laos is a tributary of the Mekong River. The river is about 415 kmlong with a catchment area of about 17,000 km2. The Nam Ngum 1 dam has an effective storage
capacity of 4.7 billion m3, located in the middle stream of the basin (Fig. 1).

Fig. 1 Nam Ngum River basin
The Nam Ngum 1 dam is dedicated to power generation, and supplies electricity to the Laos
capital, Vientiane, as well as exporting it to Thailand. The estimated basin population is 420
thousand persons and the average population density of the basin is about 25 people/km2. The basin
area accounts for 7% of the total land area and the basin population accounted for 9% of the total
population of Laos in 2000. The sewerage penetration rate in Laos is estimated to be 19.2%, but
this is mainly in urban areas.
Modernization in the agricultural sector is also lagging, with an irrigation rate of only 11%.
According to interviews in farming villages near Vientiane, the amount of fertilizer applied is stillⒸ ISERD

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low, averaging 25 kgN/ha/season, and some farmers do not apply any fertilizer in rainfed paddy
fields. The land use in the basin is paddy fields (16%), forests and bushes (72%), and residential
land (only 0.2%). The Nam Ngum 2 dam (effective storage capacity: 2.6 billion tons, completed in2011) and the Nam Ngum 5 dam (effective storage capacity: 250 million tons, completed in 2012)
are already in operation in the basin (Kudo et al., 2013), but this study considered only the Nam
Ngum 1 dam, because the meteorological, hydrological data required for the model simulation, andcollected from the hydro yearbook published by the Mekong River Commission, were only
available from 1995-2004. Water samples were collected monthly at Pakkanhoung station and thetotal nitrogen concentration was measured at the National University of Laos in 2003-2004.
Additionally, a field survey on water use, water treatment, irrigation, and cultivation methods wereconducted in the KM6 irrigation area in Nam Ngum basin. The factors affecting the water
environment can be broadly classified into point source loadings from people and livestock andnon-point source loadings from forest, farmland and urban areas. For the point source load,
statistical data, such as those on population and number of livestock, were collected from the
Bureau of Statistics, and the units of nitrogen loading in the Mekong River basin were used
(Tanaka et al., 2013). In Laos, households use septic tanks, is the simplest facility in sewage
treatment. The tanks receive domestic wastewater, which is treated by sedimentation and anaerobic
decomposition before the supernatant liquid is discharged into the drainage river. In Laos, thetemperature is high all year round, and the active decomposition of microorganisms is expected to
rapidly decompose excreta, but the treatment efficiency is extremely low due to lack of proper
maintenance. Livestock excrement is directly disposed in farmland and grassland, then discharged
into the ground water system after decomposition and absorption processes in the surface soil.
Rainfall-Runoff Model
To evaluate nitrogen transportation according to the river water flow, a distributed water cycling
model was developed and applied to analyze the water balance in the basin. TOPMODEL wasemployed for the rainfall-runoff analysis. Such a distributed model can include the spatial
distributions of topography, land use, and soil characteristics. Therefore, TOPMODEL is widelyused for hydrological characteristic analysis, water management, water quality analysis, and futureforecasting. TOPMODEL was proposed by Beven and Kirkby (1979) based on the contributing
area concept in hill slope hydrology. This model is based on the exponential transmissivity
assumption, which leads to a topographic index ln(a/To/tanb), where a is the upstream catchment
area draining across a unit length, To is the lateral transmissivity under saturated conditions, andtanb is the local gradient of the ground surface. Fig. 2 illustrates the conceptual structure of thewater cycle as estimated by TOPMODEL. Additionally, a dam operation model was combined with
TOPMODEL to calculate water storage in the reservoirs (Hanasaki et al., 2007). For details, please
see Yoshida et al., 2017.
Nitrogen Balance Model
A conceptual nitrogen balance model considering three pools in soil such as organic N, Ammonium
N and Nitrate N was developed for this study, as shown in Fig. 3. Soil N, mainly present in organic
form, is almost unavailable to plants.
The vegetation mainly uses inorganic forms of N, which are made available by organic matterdecomposition. Soil microorganisms convert the N contained in organic matter in a process calledmineralization. Although plants can use both forms of inorganic N, Nitrate is preferred because ofits greater solubility in water. In other words, nitrates quickly dissolve in the pore solution, which istaken up by plants. On the other hand, this also means that nitrate is easily leached to groundwater.
Ammonium N is less mobile because it strongly adsorbs on clay minerals due to its positive charge.
Denitrification is the anaerobic microbial reduction of N, and is used as an electron acceptor,
resulting in the transfer of soil nitrogen to the atmosphere.
The budget of each pool is expressed in the following equations.
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(1)

(2)

(3)
where Norg is organic nitrogen (kg/ha), PSNL is input N from point-sources (kg/ha/day), MinerN is
the mineralization rate (kg/ha/day), RunoffN is the nitrogen loss by surface runoff (kg/ha/day),Nammo is ammonium nitrogen (kg/ha), DepoN is nitrogen deposition (kg/ha/day), FertiN is
fertilized nitrogen (kg/ha/day), NitriN is the nitrification rate (kg/ha/day), Nnitra is nitrate nitrogen(kg/ha), PupN is the plant uptake rate (kg/ha/day), DenitN is nitrate nitrogen loss by denitrification(kg/ha/day), and LeachN is nitrate nitrogen loss by leaching (kg/ha/day). For details on thecalculation methods for each nitrogen flux and denitrification process, please see Yoshida et al.,2017.

Fig. 2 TOPMODEL structure

Fig. 3 Structure of the nitrogen balance model in soil
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Future Population Growth and Fertilizer Increase Scenarios
According to the United Nations prediction of 2000, the Laos population will increase 2.1 times by
2050. At the same time, chemical fertilizer use will also increase to produce sufficient food byagricultural modernization. This study evaluated the impacts of such population and fertilizer
increases on nitrogen loading in the Nam Ngum River basin. In 2000, the total population of Nam
Ngum basin was 420 thousand. Therefore, a population increase of 460 thousand people by 2050
was assumed and used for impact analysis. Additionally, we assumed that fertilizer use would
increase from 25 kgN/ha/season to 50 kg/ha/season to check the sensitivity of the model.
RESULTS AND DISCUSSION
Using the proposed model, water and nitrogen balances from 1995 to 2004 in the Nam Ngum Basin
were calculated at a 1 km × 1 km resolution. The first 5 years of data were used for parameter
calibration and the latter 5 years of data were used for validation. Parameters were calibrated bytrial-and-error method to maximize the Nash-Sutcliffe efficiency (NSE) of discharge and total
nitrogen (TN) concentration at Pakkanhoung (catchment area: 14,300 km2) station. Fig. 4 shows
the observed and calculated river discharge at Pakkanhoung station. The estimated NSE in thecalibration and validation periods were 0.54 and 0.50, respectively.

Fig. 4 Calculated and observed river discharge at Pakkanhoung station

Fig. 5 Calculated and observed TN concentration at Pakkanhoung stationⒸ ISERD180

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Model performance can be evaluated as “satisfactory”, if NSE > 0.50 (Moriasi et al., 2007).
The reason for the relatively low accuracy is that the input rainfall was only one point at
Pakkanhoung station. Fig. 5 shows a comparison of the calculated and measured TN concentrations
at Pakkanhoung station. The data used in this study were TN concentrations that were measured by
the authors from 2003-2004; the observed and calculated TN concentrations are compared here.
The correlation coefficient between the calculated and observed values was R = 0.75, indicatingthat the calculated values were slightly overestimated compared to the observed values. The
estimated average annual nitrogen load at Pakkanhoung station was 11,676 t/year and 8.1
kg/ha/year per unit area. Fig. 6 shows the spatial distribution of the annual mean TN concentration(1995-2004) and population density (persons/km2) map in 2000. In the Nam Ngum River basin, thetotal nitrogen concentration was almost less than 1 mg/L because of low population density andlow fertilizer use in the farmland. This analysis found that the total nitrogen concentration was notaffected by the spatial distribution of population density but was calculated to be relatively high inthe farmland during simulation periods.

Fig. 6 Spatial distribution of (a)annual mean total nitrogen concentration and(b) population density (persons/km2)

Fig. 7 Change in annual mean nitrogen load under the future scenarios
Fig. 7 shows the change in annual mean nitrogen load under the population growth andfertilizer increase scenarios. The population of the Nam Ngum River basin was 420 thousand in2000 and will increase 2.1 times to 860 thousand in 2050. The nitrogen load did not change
significantly (11,676 t/year in 2000 and 11,822 t/year in 2050) as a result of population increase in
the basin. The maximum population density in the Nam Ngum River basin in 2000 was about 2,140
persons/km2, with most people living in rural areas. Even if the population were to increase by 2.1
times, the population density would remain low; thus, there would be no significant impact on theⒸ ISERD

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water quality environment of the basin. The fertilizer increase scenario, however, from 25
kg/ha/season to 50 kg/ha/season, showed a significant increase in nitrogen loading, from 11,676 t/year
to 17,010 t/year. The current fertilizer application rate is 25 kgN/ha, which is extremely low. To
increase food production in response to future population growth, it is necessary to increase
production per unit area. Therefore, we assumed a scenario of increasing the amount of applied
fertilizer and evaluated the impact on the water quality environment of the watershed. Doubling thefertilizer application rate to 50 kg/ha resulted in a 46% increase in the annual nitrogen load at
Pakkanhoung station. The nitrogen discharge load per unit area increased from 8.1 kg/ha/year(equivalent of 0.66 mg/L) to 11.8 kg/ha/year (equivalent of 0.95mg/L) under this scenario, however,
the water quality environment was still favorable.
CONCLUSION
The Nam Ngum River basin, Laos, which supplies high quality domestic water to Vientiane
Metropolis, was selected as the target area for this study. The UN has estimated that the populationin Laos will increase by 2.1 times between 2000 and 2050, and producing sufficient food for thehigher population will require increased fertilizer use. Therefore, changes in future water quality is
the main concern for this river basin. Meteorological and hydrological data from 1995 to 2004, andspatial data such as topography, land use, and soil properties were collected for model simulation.
A conceptual nitrogen balance model with three nitrogen pools was developed and combined withthe rainfall runoff model. Simulated river discharge and nitrogen loading agreed with the observed
data. Next, we investigated future variations of nitrogen loading in the basin under the population
growth and agricultural modernization scenarios. As a result, even when population in the basin
increased by 2.1 times, the nitrogen load did not change significantly (11,676 t/year in 2000 and
11,822 t/year in 2050). However, the fertilizer increase scenario, from 25 kg/ha/season to 50
kg/ha/season, showed a significant increase in nitrogen load from 11,676 t/year to 17,010 t/year.
Our results provide a first insight into the magnitude and spatial distribution of nitrogen loading in
Nam Ngum River Basin. This type of model may be useful for future impact assessments.
ACKNOWLEDGEMENTS
This research was supported by JST SICORP Grant Number JPMJSC20E3, and the MEXT/JSPS
Grant-in-Aid for Scientific Research (KAKENHI) no. 19H03069 and no. 20KK0346.
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02626667909491834
Conan, C., Bouraoui, F., Turpin, N., De Marsily, G. and Bidglio, G. 2003. Modeling flow and nitrate fate atcatchment scale in Britany (France). Journal of Environmental Quality, 32 (6), 2026-2032, Retrieved
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Hanasaki, N., Utsumi, N., Yamada, T., Shen, Y., Bengtsson, M., Kanae, S., Otaki, M. and Oki, T. 2007.
Development of a global integrated water resources model for water resources assessments under climatechange. Annual Journal of Hydraulic Engineering, JSCE, 51, 229-234, Retrieved from DOI https://doi.
org/10.2208/prohe.51.229 (in Japanese)
Kudo, R., Masumoto, T., Horikawa, N. and Yoshida, T. 2013. Assessment of combined impact of climatechange and water resources development on hydrological cycle in the Nam Ngum River Basin.
Transactions of JSIDRE, 81 (1), 57-66. (in Japanese).
Lee, M.S., Lee, K.K., Hyuna, Y., Clement, P.T. and Hamilton, D. 2006. Nitrogen transformation andtransport modeling in groundwater aquifers. Ecological Modelling, 192, 143-159, Retrieved from DOI
https://doi.org/10.1016/j.ecolmodel.2005.07.013
Moriasi, N.D., Arnold, G.J., Liew, W.M. van, Bingner, L.R., Harmel, D.R. and Veith, L.T. 2007. Modelevaluation guidelines for systematic quantification of accuracy in watershed simulations. Transactions ofⒸ ISERD

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the American Society of Agricultural and Biological Engineers, 50 (3), 885-900.
Tanaka, K., Yoshida, K., Noda, K., Azechi, I. and Kuroda, H. 2013. Estimation of unit of nitrogen andphosphorous pollution loading in Mekong River Basin. Transactions of JSIDRE, 81 (2), 193-199. (inJapanese).
Whitehead, G.P., Wilby, L.R., Butterfield, D. and Wade, J.A. 2006. Impacts of climate change on in-stream
nitrogen in a lowland chalk stream: An appraisal of adaptation strategies. Science of the Total
Environment, 365, 260-273, Retrieved from DOI https://doi.org/10.1016/j.scitotenv.2006.02.040
Yoshida, K., Tanaka, K., Noda, K., Homma, K., Maki, M., Hongo, C., Shirakawa, H. and Oki, K. 2017.
Quantitative evaluation of spatial distribution of nitrogen loading in the Citarum River Basin, Indonesia.
Journal of Agricultural Meteorology, 73 (1), 31-44, Retrieved from DOI https://doi.org/10.2480/agrmet.D-15-00020Ⓒ ISERD

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Research article
erd

Nursery Propagation of Apple Mangrove Sonneratia alba
ARNIE C. TRANGIA*
Cebu Technological University, Cebu City, Philippines
Email: arnie.trangia@ctu.edu.phReceived 7 February 2022

Accepted 2 May 2022(*Corresponding Author)

Abstract Mangrove rehabilitation conducted on the seafront was a failure because of small
survival due to wrong species planted and zonation. Apple mangrove (Sonneratia alba),"pagatpat," is the most widely distributed mangrove globally, particularly in coastal regions.
The study showed that the Sonneratia species bears plenty of fruits, but seedlings rarely
grow in the wild. The researcher introduced a ninety-day analysis using various soil media
and different watering regimes in a designed concrete tank to determine the survival andgrowth rates of the nursery propagated apple mangrove seedlings. He observed that thehighest average survival rate of S alba seedling was in watering regime Treatment 3 and thetype of soil medium was sandy clay. The researcher measured the average survival rate at
23.70% in clay, 52.10% for sandy clay, 44.32% for sandy soil under a watering regime,
37.41% in clay, and 43.21% in sandy clay, and 39.41% in sandy soil. Research showed thatthe seedlings watered under Treatment 3 observed the highest growth gain (5.41 ± 0.68 cm),while seedlings under Treatment 1 recorded the lowest growth gain (1.87 ± 0.23 cm) under
the watering regime. Seedlings planted in sandy-clay soil exhibited the highest growth gain
(4.15 ± 0.52 cm), while seedlings planted in clay recorded the lowest growth gain (4.0 ±0.50 cm) for soil media. Moreover, the researcher observed that growth showed asignificant difference in the different watering regimes but had no significant difference inthe type of soil media.
Keywords apple mangrove, water regimes, soil media, survival rate, growth rate

INTRODUCTION
The Philippines is ranked fourth out of the 180 countries in the 20 years (2000-2019), following
Puerto Rico, Myanmar, and Haiti among the countries most affected by extreme weather according
to the Germanwatch report (Global Climate Index, 2021).
Mangroves are a natural coastal defense against violent storms that bring storm surges andflooding. It is one of the most effective mitigating measures against climate change. In addition,
mangroves can hold back the sea waves and reduce wave forces with their extensive and dense
above-ground roots by an estimated 70-90% on average (Macintosh, 2010). Furthermore, a study
conducted by Harada et al. (2012) demonstrated that mangroves are as effective as concrete seawall
structures in reducing tsunami-hit house damage behind the forest.
Mangrove systems have contributed significantly to the well-being of coastal communities
through a wide array of ecosystem services classified into regulating, provisioning, cultural, andsupporting (Manual on Community-Based Mangrove Rehabilitation: Box 1, 2012). Fringing
mangroves in the Philippines and the rest of Southeast Asia are naturally lined by a band of
Avicennia marina and Sonneratia alba front-liners with Rhizophora stylosa and R. apiculate
immediately behind (Manual on Community-Based Mangrove Rehabilitation, p. 6, 2012).
Primavera et al. (2014) averred that Sonneratia alba (pagatpat) dominates the eastern Panay
coastline. The species has been proven superior even to the Avicennia marina for the rehabilitationof sandy fringes. Most of the plantations used Rhizophora species whose propagules are easy tocollect and plant but which cannot withstand wave action. Hence only 10% of these plants survived
in open seaward sites in Calauag Bay, Quezon. These activities can best describe as planting by
convenience rather than ecology (Primavera, 2005; Primavera and Esteban, 2008).
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Avicennia marina and Sonneratia alba are the two significant fringing colonizers of thecoastlines. However, wildlings are much rarer than the latter, and nursery techniques are relatively
undeveloped compared to the first, according to protocols for growing Sonneratia alba (Mangrove
Manual Series No. 2: Box 7, 2012).
Mangrove rehabilitation/reforestation programs in seafront areas and building coastal
greenbelts as a mitigating measure in protecting coastal communities can still be a total failure.
Develop the nursery propagation of apple mangrove first since this species is the primary colonizerof the sandy fringing coastlines. It is a suitable mangrove species to be planted in the seafront zone.
Moreover, it is bigger, sturdier, and can withstand nature's forces as compared to the usual
Rhizophora species.
The study used a tide simulation to address the gap using different watering regimes of pure
seawater and various soil media. Using a concrete tank regulates the additional watering controls.
Inundation of seawater to the seedlings should not be more than 30 percent of the time per day. The
production of nursery propagated seedlings will fill the gap of the rareness of apple mangrove
seedlings. The establishment of mangrove nurseries can provide mangrove seedlings of therequired species in the required numbers and sizes at a given time; otherwise, planting will behighly dependent on the availability of propagules, seeds, or wildlings (Mangrove Manual SeriesNo. 1: Box 3, 2012).
OBJECTIVE
The purpose of this research study is to produce nursery reared apple mangrove seedlings to supply
the much-needed right planting materials and to correct the existing practice of coastal mangrove
rehabilitation/reforestation using Rhizophora species. Specifically, the study aimed to: (1)determine the survival rate of Sonneratia alba seedlings reared in three types of soil media using
different watering regimes; (2) assess the growth rate of apple mangrove seedlings reared in three
types of soil media using different watering regimes; and (3) conduct pilot testing to assess what
type of soil media and corresponding watering regime propagated apple mangrove seedlings grow
best.
METHODOLOGY
The environment: The researcher conducted apple mangrove (Sonneratia alba) nursery
propagation research in Daanbantayan, Cebu, Central Philippines.

LEGEND:T1= watered with seawater once a day (the natural way)
T2= watered once a day (totally submerged for two hours)
T3= watered with seawater twice a day (totally submerged for two hours for each treatment

Fig. 1 The design of the research tank
The concrete tank: The study used a concrete tank measuring 8 meters in length by 2 meters inwidth by 0.24 meters in depth (8 m x 2 m x 0.24 m.). The tank is further subdivided into 16
compartments; measuring approximately one square meter in area respectively (Fig. 1).

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The plant pot and soil media: The research used 18 centimeters in diameter synthetic pots in its
top portion by 15 centimeters in height, and it utilized three types of soil media treatments, sandy,
sandy clay, and clay. Each treatment used nine pots, each filled with the corresponding soil. Since
there will be three treatments with five replications, the total number of banks used was 45 in eachtreatment or 135 pots for all the three treatments.
Seedling preparation phase: Mature bigger fruits that had no holes bored by insects do not sufferfrom extreme weather conditions, and were ripe in a good parent tree, were collected early in themorning or late in the afternoon through handpicking. Fruits of S. alba will freely fall when ripeand mature and naturally separate from their calyx before dropping to the ground (Fig. 2).

Fig. 2 Ripe fruit and seeds of Sonneratia alba ideal for collection
By using the bare hands, macerate the fruits by pressing. Usually, the number of seeds foundinside ranged from 80 to 160. The seeds were soaked and washed in a basin withfreshwater/rainwater and let stand for a few minutes allowing the viable seeds to float. The seeds
were dried for 2 to 3 hours to break seed dormancy. Avoid prolonged drying of sources, for it willaffect seed germination.
The study utilized seedboxes measuring 40 x 90 cm. Sandy clay soils were used as soil
medium (5-7 cm thickness) and taken from the parent tree area. The seeds were soaked overnightwith rainwater to hasten germination. After twenty-four (24) hours, the seeds that showed signs ofsprouting were collected and sown in the seedboxes, covered with 2.54 cm-thick soil, and allowed
to germinate for one month before transplanting individually. Water the seeds with rainwater
diluted with seawater to acclimatize the seeds. After 30 days of propagation from the seedbed, theresearcher transplanted the seedlings.
Experimental phase: The tank's 15 compartments should be re-checked carefully for its watertightworthiness by filling the tank with seawater and cross-checking the draining system to see if it
functions well. The study closely followed the watering regime scheduled time during the floodingof the tanks. The researcher should do general cleaning of the tank every fifteen days.
Watering regimes: In treatment 1, the plants were watered once, just like ordinary plants.
Treatment 2 was submerged once for two hours daily, and Treatment 3 was submerged twice fortwo hours in each submersion. Two cm above the apex of the seedling's leaves, seawater was
inundated. Drain the tank's compartments by pulling out the cover of the drainage pipe after twohours. The researcher simulated treatments like the tide of the sea, which coincides with the study(Kjerfe 1990) that mangroves grow at or above mean sea level or MSL, which is not more than thesea 30% of the time tidally inundated.
Seedling management: The study used three treatments of different soil media and three watering
regimes with five replications each. The study needed an adequate and accessible supply of clean
seawater to efficiently facilitate the filling-up and drain of the seawater in the tank. The project
should strictly follow a watering schedule. After ninety (90) days of managing period, the seedlings
are now ready for extension purposes by planting the produced seedlings in the selectedrehabilitation areas.

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Collection of data: During the initial stage of transplanting, the seedlings had an initial height of 2
centimeters. The researcher measured the seedlings from the top of the soil to the last middle leafof the plant. Every 15 days, the plant's data, survival, and growth rate were taken and monitored forthree months.
Statistical treatment: The study used a Randomized Complete Block Design (RCBD) research
design. A two-way ANOVA of SPSS Statistics to get the mean difference to determine if there is asignificant difference in survival rate and growth rate in the three watering regimes and threedifferent soil media. The variables studied survival rate and growth rate. The study used following
Equation (1) to get the survival rate.
Number of survivors
Surviving rate =

(1)

x 100
Initial number

The growth rate was taken using following Equation (2).
Growth rate = Height 1 - Height 2/ Height 1 x 100(2)

RESULTS AND DISCUSSION
Survival rate: Figure 3 showed a significant relationship between the watering regime andSonneratia alba's survival. The survival rate of S. alba was highest in Treatment 3, was increased in
Treatment 2, but very low in Treatment 1. The experiment implies that the inundation of seawater
twice daily favors the survival of Sonneratia alba seedlings as long as the submersion time was not
more than 30% of the time. The inundation of fresh seawater brought nutrients to seedlings. The S.
alba average survival rate in the three watering regimes is highest in sandy-clay soil with 43.21%,
sandy soil with 39.41%, and clay with 37.41%.

Fig. 3 Survival rate of the apple mangrove seedlings in various treatment
The study implies that in the soil type where most of its parent trees lived, S. alba seedlings
survive best. However, this is in contrast to Deloffre et al. (2006) and Viles et al. (2008) study,
which showed that for both Aviccenia and Sonneratia, short inundation (5 h day -1) without
sediment treatment resulted in 100% survival throughout the experiments.
Results of analysis of variance (ANOVA) computation revealed a significant relationship on
the survival of S. alba in different watering regimes (p=.000<0.05) at a 5% level of probability; but
has no meaningful relationship with the survival of S. alba in other soil media (p=0.493 > 0.05) at
5% level of probability also. Furthermore, it has no significant effect on the survival of S. alba
seedlings in the different watering regimes and soil type interaction (p=0.125>0.05) at a 5%
probability level.
ANOVA implies that within the duration of the study the survival of S. alba seedlings has asignificant difference when watered naturally, submerged once a day, or submerged twice a day but
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of S. alba seedlings has no significant difference whether watered naturally, submerged once a day,or submerged twice a day interacted with different soil mediums.
Table 1 Analysis of variance (ANOVA) table on survival rate
SourceCorrected modelIntercept
Watering regime
Soil type
Watering regime * Soil type
Error
Total
Corrected total

Type IIISum of squares
9720.335a
86577.691
7753.435
311.275
1655.626
9746.515
106044.541
19466.850

Meansquare1215.042
86577.691
3876.717
155.637
413.906
216.589

df
8
1
2
2
4
45
54
53

F

P-value

5.610
399.732
17.899
.719
1.911

.000
.000
.000
.493
.125

Growth rate: The study used an estimated margin of 4.0 cm to interact with the watering regime
and soil type if it affects the growth of the S. alba seedlings. All the seedlings planted in different
soil media interacted with the watering administration. The study found that Treatment 3 andTreatment 2 were above the estimated marginal means.

y = 0.34x + 4.73
R² = 0.9772
5.10
4.57

2.32

5.78
5.27
y = 0.35x + 4.1933
R² = 0.9829

5.35
4.84

y = -0.46x + 2.7867
R² = 0.9994
1.88

1.40

Fig. 4 Growth rate of the apple mangrove seedlings in various treatment
It means that the result of the study coincides with the report of Kjerfe (1990) that mangroves
grow at or above mean sea level or MSL, which is not more than 30% of the time tidally inundated.
Results of Analysis of Variance (ANOVA) showed a significant relationship on the growth of
S. alba in different watering regimes (p=.000<0.05) at a 5% level of probability; but has no vital
relationship with the survival of S. alba in other soil media (p=0.9777>0.05) at 5% level ofprobability also. Furthermore, it has no significant effect on the survival of S. alba seedlings in the
different watering regimes and soil type interaction (p=0.909>0.05) at a 5% probability level.
Table 2 Analysis of variance (ANOVA) table on the growth rate
SourceCorrected modelIntercept
Watering regime
Soil type
Watering regime * Soil type
Error
Total
Corrected total

Type IIISum of squares
137.488a
888.491132.035.240
5.213
235.939
1261.918
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df
8
1
2
2
4
45
54
53

Mean
F
square17.1863.278
888.491 169.460
66.018 12.591
.120
.023
1.303
.249
5.243

P-value
.005
.000
.000
.977
.909

IJERD – International Journal of Environmental and Rural Development (2022) 13-1

It implies that within the span of the study from days 0-90, the growth of S. alba seedlings has
a significant difference when watered naturally, submerged once a day, or submerged twice a day
but has no significant difference when grown in clay, sandy-clay, or sandy soil. Moreover, thegrowth of S. alba seedlings has no significant difference whether watered naturally, submerged
once a day, or submerged twice a day interacted with different soil mediums whether grown in clay,
sandy clay, or sandy soil.
CONCLUSION
The study can conclude that the soil medium having the highest average survival of Sonneratia
alba seedlings grown in the concrete tank is the sandy-clay soil. The ideal watering regime for their
growth is Treatment 3, in which the seedlings are submerged twice for two hours per submersion.
With this study, the production of the correct species of mangrove seedlings is available, and theoutput can correct the present trend of mangrove rehabilitation/reforestation. Because of thisresearch saves much time, effort, and money. The paper can realize the long-term dream ofbuilding coastal greenbelts to make the coastal community well-protected and resilient against thethreats of climate change and global warming.
REFERENCES
Barbier, B.E., Hacker, D.S., Kennedy, C., Koch, W.E., Stier, C.A. and Silliman, R.B. 2011. The value of
estuarine and coastal ecosystem services. Ecological monographs, 81 (2), 169-193.
Bosire, O.J., Dahdouh-Guebas, F., Walton, M., Crona, I.B., Lewis, R.R., Field, C. and Koedam, N. 2008.
Functionality of restored mangroves: A review. Aquatic Botany, 89, 251-259.
Carter, N.H., Schmidt, W.S. and Hirons, C.A. 2015. An international assessment of mangrove management:
Incorporation in integrated coastal zone management. Diversity, 7 (2), 74-104.
Clarke, A. and Johns, L. 2002. Mangrove nurseries: Construction, propagation and planting. Queensland
Department of Primary Industries.
Global Climate Risk Index. 2021. Who suffers most from extreme weather events? Weather-related loss
events in 2019 and 2000 to 2019. Retrieved from https://www.germanwatch.org/en/cri
Kirui, B., Huxham, M., Kairo, G.J. and Skov, W.M. 2008. Influence of species richness and environmental
context on early survival of replanted mangroves at Gazi bay, Kenya. Hydrobiologia, 603 (1), 171-181.
Primavera, H.J. 2009. A field guide to Philippine mangroves. Retrieved from https://repository.seafdec.org/
handle/20.500.12066/6662
Primavera, H.J. and Esteban, A.M.J. 2008. A review of mangrove rehabilitation in the Philippines: Successes,
failures and future prospects. Wetlands Ecology and Management, 16 (5), 345-358.
Primavera, H.J., Rollon, R. and Samson, S.M. 2011. The pressing challenges of mangrove rehabilitation:
Pond reversion and coastal protection. Biologica, 50, 232.
Primavera, H.J., Sadaba, B.R., Lebata, L.H.J.M. and Altamirano, P.J. 2004. Handbook of mangroves in thePhilippines-Panay. SEAFDEC Aquaculture Department. Iloilo, Philippines.
Primavera, H.J., Savaris, P.J., Bajoyo, E.B., Coching, D.J. Curnick, J.D., Golbeque, L.R. Guzman, T.A.
Henderin, Q.J., Joven, V.R., Loma, A.R. and Koldewey, J.H. 2012. Manual on community-basedmangrove rehabilitation. Mangrove Manual Series, 1, 240.
Roldan, R.G. and Mayo-Anda, G. 2004. An assessment of fish sanctuary and mangrove rehabilitation
projects established under the fisheries resource management project. Fisheries Resource Management
Project.
Schmitt, K. and Duke, C.N. 2015. Mangrove management, assessment, and monitoring. Tropical Forestry
Handbook, 1-29.
Viles, A.H., Naylor, A.L., Carter, A.E.N. and Chaput, D. 2008. Biogeomorphological disturbance regimes:
Progress in linking ecological and geomorphological systems. Earth Surface Processes and Landforms,
The British Geomorphological Research Group Journal, 33 (9), 1419-1435.
Walters, B.B. 2003. People and mangroves in the Philippines: Fifty years of coastal environmental change.
Environmental Conservation, 30 (3), 293-303.

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erdInternational Society ofEnvironmental and Rural Development

Philosophy of ISERD:
Recently, in developing countries, subsistence agriculture is being converted to export-oriented mono-culture,and the amounts of agricultural chemicals applied to the farmland are increasing every year. The appliedchemicals in farmland cause serious environmental problems downstream such as eutrophication, unusual
growth of aquatic plants, decrease in dissolved oxygen and accumulation of bottom mud in water resources.
Also, there seem to be many cases in which people apply agricultural chemicals without understanding its
impact to health and food safety. Therefore, it is necessary to promote and enhance understanding ofsustainable rural development among local stakeholders including farmers.
Sustainable rural development aims to meet human needs while preserving the natural environment. As
it should cover not only social and economic development but also natural environment conservation, no
single organization can achieve sufficiently the aspirations of sustainable rural development. Collaboration
among international, governmental and non-governmental organizations, together with the academe andscientific sector, is indispensable.
The knowledge and intelligence accumulated in universities and research institutions are also expected
to make the programs facilitated by the international, governmental and non-governmental organizations
more adequately implemented and meaningful to societal development. However, these cases especiallythose implemented locally have been scattered without having been summarized well or recorded in annals
academic or scientific societies.
So, the International Society of Environmental and Rural Development founded in 2010, aims to discussand develop suitable and effective processes or strategies on sustainable rural development focusing on
agricultural and environmental aspects in developing countries. The ultimate goals of the society are tocontribute to sustainable rural development through social and economic development in harmony with thenatural environment, and to support the potential or capacity building of local institutions and stakeholders in
the rural area with academic background.

Purposes of ISERD:
The primary purposes of ISERD are to contribute to sustainable rural development through social andeconomic development in harmony with the natural environment and to support the potential or capacity
building of local institutions and stakeholders in the rural area with academic background.
In order to enhance the realization of the primary purposes of ISERD, the secondary purposes are;- to facilitate interaction among international, governmental, non-governmental organizations and local
communities,- to hold conferences or symposia on environmental and rural development,- to edit the International Journal of Environmental and Rural Development,- to confer some awards based on scientific achievement, research paper or poster presentation, and- to encourage and develop local awareness concerning sustainable rural development.

Membership:
There shall be two categories of membership.
(a) Individual(b) Organizational
An application for membership of ISERD shall be submitted to the secretariat of ISERD, where is located in
the Research Center at Institute of Environmental Rehabilitation and Conservation (Japan) by writing or byother appropriate means.
Also, every presenter who attends the International Conference on Environmental and Rural
Development (ICERD) is registered as an Individual Member of ISERD.

IJERD – International Journal of Environmental and Rural Development

Council of ISERD:
The affairs of ISERD shall be governed and managed by the ISERD Council. The councilors are as follows.
President
Prof. Dr. Mario T. Tabucanon, United Nations University Institute for the Advanced Study of
Sustainability, Japan
Deputy Presidents
Prof. Dr. Bunthan Ngo, Royal University of Agriculture, Cambodia
Prof. Dr. Anan Polthanee, Khon Kaen University, Thailand
Prof. Dr. Eiji Yamaji, The University of Tokyo, Japan /Institute of Environmental Rehabilitation and Conservation, Japan
Executive Secretary / Editor-in-Chief of IJERD
Prof. Dr. Machito Mihara, Tokyo University of Agriculture, Japan /Institute of Environmental Rehabilitation and Conservation, Japan
Managing Editors
Dr. Narong Touch, Tokyo University of Agriculture, Japan
Dr. Shinobu Terauchi, Institute of Environmental Rehabilitation and Conservation, Japan
Dr. Jeeranuch Sakkhamduang, Institute of Environmental Rehabilitation and Conservation /Association of Environmental and Rural Development, Thailand
Treasurer
Dr. Lalita Siriwattananon, Rajamangala University of Technology Thanyaburi, Thailand
Regional Vice Presidents
Dr. Shafiqullah Rahmani, Ghanzni University, Ministry of Higher Education, Afghanistan
Prof. Dr. Barry N. Noller, The University of Queensland, Australia
Prof. Dr. Sinisa Berjan, Embassy of Bosnia and Herzegovina in Japan /University of East Sarajevo, Bosnia and Herzegovina
Dr. Buntong Borarin, Royal University of Agriculture, Cambodia
Prof. Dr. Ping Li, Institute of Grassland Research, China
Prof. Dr. Dieter Trautz, Osnabrück University of Applied Sciences, Germany
Dr. Sri Wahyuni, Islamic University of Riau, Indonesia
Dr. Kasumi Ito, Nagoya University, Japan
Prof. Dr. Nang Hseng Hom, Yezin Agricultural University, Myanmar
Prof. Dr. Junaid Alam Memon, Institute of Business Administration Karachi, Pakistan
Prof. Dr. Regucivilla A. Pobar, Bohol Island State University, Philippines
Dr. Chuleemas Boonthai Iwai, Khon Kaen University, Thailand
Dr. David R. Ader, University of Tennessee, USA
Dr. Nguyen Khoi Nghia, Cantho University, Vietnam

ISERD Secretariat:
Research Center, Institute of Environmental Rehabilitation and Conservation (ERECON)
2987-1 Onoji Machida-shi, Tokyo 195-0064, Japan
Tel/Fax: +81-42736-8972
E-mail: iserd.secretariat@gmail.com
Webpage: www.iserd.net
Collaborated with

Association of Environmental and Rural Development (AERD)
93/64 Moo.3, Sinsab Village 2, Bungyeetho Sub-Ddistrict, Thanyaburi District,Pathum Thani 12130, Thailand
Tel/Fax: +66-2957-8064
E-mail: iserd.secretariat@gmail.com
Webpage: www.iserd.net

Institute for the Advanced Studyof Sustainability
All articles and reports published in this journal were accepted through a peer-review process. However,most articles and reports published in this journal were presented at the International Conference on
Environmental and Rural Development that was co-organized by United Nations University Institute for the
Advanced Study of Sustainability.

IJERD – Environmental and Rural Development

Vol. 13 No. 1

June 2022