IJERD – International Journal of Environmental and Rural Development (2018) 9-1

Research article
erdComparison of Soil Properties of Farmlands Applied withOrganic and Inorganic Fertilizers in Kampong Cham
Province, Cambodia
MUY LEANG KIM
Graduate School of Agriculture, Tokyo University of Agriculture, Japan
Email: muyleangkim70@gmail.com

TORU NAKAJIMA
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan

MACHITO MIHARA*
Faculty of Regional Environment Science, Tokyo University of Agriculture, Tokyo, Japan
Email: m-mihara@nodai.ac.jp
Received 1 January 2018

Accepted 12 May 2018(*Corresponding Author)

Abstract In Cambodia, soil capability for rice production in lowlands has been almost
documented, but only little is known about the properties of upland soils for growing nonrice crops. Current agricultural land use practices together with severe climatic conditions
and population pressure have led to soil degradation, loss of soil fertility which declining
crop yield and increase the risk of malnutrition. Therefore, the objectives of this study were
1) to compare the soil properties of farmlands applied organic and inorganic fertilizers, 2) tomeasure the organic fertilizer dependence in Samraong and Baray Communes. The
questionnaire survey was conducted and farmer representatives were interviewed. Soilsamples were collected from 20 different locations. Soil samples were analyzed for its pH,
Electrical conductivity (EC), organic matter, total nitrogen (T-N), total phosphorus (T-P),
calcium (Ca2+), potassium (K+), sodium (Na+), water content, and permeability, and thePearson coefficient correlation was used for the statistical analysis. Organic fertilizer
dependence was classified into 3 categories not dependent, moderately dependent andhighly dependent, 40.0%, 30.0%, and 30.0%, respectively. The results of statistical analysis
showed that in Samraong Commune there was no trend detected, despite in Baray
Commune there was positive trend detected between organic fertilizer dependence and soilproperties.
Keywords soil properties, fertilizers, organic, inorganic, dependency

INTRODUCTION
Cambodia is located in the southern portion of Indochina peninsula, and sheared its borders withThailand, Laos and Vietnam. The total land area of Cambodia is 181,035 km2 and currentpopulation is 16.2 million in which only 78.3% is living in rural areas. Agricultural production in
Cambodia is concentrated in the northwestern districts bordering Thailand, on the central plains
surrounding the Tonle Sap Lake and its river systems, along the Mekong River towards theMekong delta. The total land use area under major agricultural crops was about 4.5 million ha(MAFF, 2012). Agricultural lands could be categorized into two distinct topographical regions
lowlands and uplands. Lowland soils mainly support rice framing interspersed with field crops,
vegetable gardens and fruit trees. Upland soils are mainly used for rubber (Hevea brasiliensis)
plantations, maize (Zea mays), cassava (Manihot esculenta), soybeans (Glycine max), mug-beans(Vigna radiata), peanuts (Arachis hypogaea), sesame (Sesamum indicum), sugarcane (Saccharumofficinarum), and fruit trees (Ministry of Agriculture, Forestry and Fisheries, Cambodia, 2012).
Moreover, the farming system in Cambodia is normally based on the application of chemicalⒸ ISERD135

IJERD – International Journal of Environmental and Rural Development (2018) 9-1

fertilizers, chemical pesticide, fungicide and herbicide (FAOSTAT, 2016). Fertilizers play a keyrole in agriculture production, cultivation of a major crop that rely on the use of high rates ofinorganic fertilizers continuously for several years, often lead to unsustainability in production andalso pose threat to the environment (Smith et al., 1990), thought chemical fertilizers are high innutrient contents and are rapidly taken up by plants but relatively expensive. Excessive use offertilizers results in various problems, such as nutrients loss, surface water and groundwatercontamination, soil acidification, reductions in useful microbial communities, and increase insensitivity of harmful insects (Chen J.H., 2006). Recent year, with the support from the government
and non-governmental organization (NGOs), many Cambodian farmers realized and looked for abetter practice which could harmonize with natural environment and human health. There wereseveral practices carried out to move forwards from the used of inorganic fertilizers to promote on
the application of organic fertilizers such as green manure, compost, and bio-liquid fertilizer insome provinces of Cambodia. With the use of organic fertilizers could eliminated and minimize theuse of inorganic fertilizers as well as improved on soil, water and environmental quality. By theseveral practices that carried to promote the use of organic fertilizers in order to meet therequirement of nutrients in soil, so each practice may contribute to difference of positive andnegative effect attributes to farmlands.
OBJECTIVES
The objectives of this study were 1) to compare soil properties of farmlands applied organic andinorganic fertilizers, and 2) to measure organic fertilizer dependence in Samraong and Baray
Communes, Kampong Cham Province, Cambodia.
METHODOLOGY
Study Site
Cambodia

Kampong Cham Province
BaraySamraong

Fig. 1 Map of the study areas
Kampong Cham Province is located in the central region of Cambodia. The population is 1.6
million. Prey Chhor District is located in Kampong Cham Province and it’s divided into 15
communes and 176 villages. The major soil types in this areas are brown hydromorphics, regurs
and cultural hydromophics (Kampong Cham Administration, 2010). Samraong and Baray
Communes were selected for this study. In Samraong and Baray Communes the population werearound 8,123 and the total number of families were 1,714 and 11 villages and 10,637 and the total
number of families were 2,446, and 13 villages, respetively. Farmers in both communes were
mostly smallholder farmers with less than 1 ha of cultivated agricultural land (CDB, 2010). In
Samraong and Baray Communes the main economic activity of farmers are rice cultivation in low
land and vegetables in upland fields are also cultivated (ERECON, 2009). In order to increase theproductivity of farmland local farmers tend to use high amount of chemical fertilizers. The numberⒸ ISERD136

IJERD – International Journal of Environmental and Rural Development (2018) 9-1of families using chemical fertilizers was around 1,587 in Samraong Commune and 1,479 in Baray
Commune. There was a project implemented to promote sustainable agriculture in Samraong
Commune by Japan International Cooperation Agency (JICA) from 2011 to 2016. The target group
comprised of 450 households in Samraong Commune. A similer project was implemented in Baray
Commune to promote organic farming through composting and liquid fertilizer by Ministry ofAgriculture, Forestry and Fisheries (MAFF), Japan from 2006 to 2009, 45 households were thetarget group.
Questionnaire Survey
Questionnaire survey was conducted in Samraong and Baray Communes. Farmer representatives
were interviewed. The questionnaire included questions about general information, economical
condition and agricultural condition as shown in Table 1.
Table 1 The contents of questionnaire survey for the field activities
Category
General information

DetailsName, Age, Gender, Level of education, Occupation
Working condition, Land areas, Crops cultivation,
Labor use in agriculture, Cost of fertilizers
Problems in agricultural land, Kinds of agro-chemicals,
Kinds of livestock

Economical condition
Agricultural condition

Soil Analysis
Soil samples were collected from 20 different locations. Soil sampling sites are shown in Fig. 2.
There were 20 disturbed and 20 undisturbed soil samples were collected from Samraong and Baray
Communes in August, 2017. Disturbed soil samples were used to analyze for its pH, EC, watercontent, organic carbon, total nitrogen, total phosphorus, particle size distribution, calcium,potassium and sodium. Undisturbed soil samples were analyzed for its permeability and bulk
density. The experiment was conducted in September, 2017. The details of soil analysis are shownin Table 2.
Table 2 Soil indicators for the laboratory activities
Physicalproperties

Water contentMethods

Gravimetricmethod

Particle size
distribution
International pipettemethodChemicalproperties

pHEC

Organic matter

Permeability

Ignition loss

Saturated hydraulicconductivity (Ksat) method

T-N and T-P

Ca2+, K+, and Na+

Absorption
Portable absorption
spectroscopy
spectrophotometer
EC: Electrical conductivity, T-N: Total nitrogen, T-P: Total phosphorus, Ksat: Saturated hydraulic conductivity,
Ca2+: Calcium, K+: Potassium and Na+: Sodium
Methods

Dilution

Dilution

Organic Fertilizer Dependence
Organic Fertilizer Dependence of the farmers in Samraong and Baray Communes was analyzed
based on nitrogen application in organic and inorganic fertilizers during complete growing season.
Total nitrogen application by farmers was calculate using equation (1) and Organic fertilizer
dependence was calculated using equation (2).
TN = A × N / 100(1)Ⓒ ISERD

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Where, TN is total nitrogen content (kg ha-1 yr-1), A is the amount of fertilizers applied (kg ha-1),
and N is the percentage of nitrogen concentration of the fertilizers (%)
OFD = (ON1 + ON2 + ON3 +…+ ONn) ÷ (ONn + INn) × 100(2)

Where, OFD is Organic Fertilizer Dependence (%), ON1 is nitrogen content in organic fertilizer (kgha-1 yr-1), ONn is total nitrogen content in all the organic fertilizers application (kg ha-1 yr-1), NIn is
total nitrogen content in all the inorganic fertilizers application (kg ha-1 yr-1).

Prey Chhor District

BaraySamraong: Sampling site

Fig. 2 Soil sampling sites
RESULTS AND DISCUSSION
Questionnaire Survey
The results from the questionnaire survey shown in Fig. 4 indicated that the representative farmers
in the study areas has total cultivated agricultural lands about 0.5 to 1 ha. This cultivated land areas
mostly used for the rice and vegetable cultivation activities in Samraong and Baray Communes.
(A)

(B)

n = 10n = 10Fig. 3 Land cultivated areas from the responded farmers in (A) and (B)Agricultural Condition
The result of agricultural condition were about the types of fertilizers used and the percentage oforganic fertilizers dependence were shown in Table 3. As shown in Table 3 there were 4 types ofcommons fertilizers used including Urea, DAP, cow manures, and compost.
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Table 3 Types of fertilizers used (kg/ha/year) from the responded farmers in Samraong andBaray Communes
SiteUrea
NDAP
N(kg/ha/yr) (kg/ha/yr) (kg/ha/yr) (kg/ha/yr)
N% (46%)

CowNCompostNTNmanure(kg/ha/yr) (kg/ha/yr) (kg/ha/yr) (kg/ha/yr)(kg/ha/yr)

N% (18%)

N% (1.587%)

150
2350
92000
31.6
2100
46100
1825000
395
3100
46100
184000
63.2
4100
46
100
183000
47.4
550
2350
90
0
6
240
110.4
240
43.2
30
0.474
720
9.2
100
18100
1.58
820
9.2
50
950
0.79
9500
230
250
45
00
1050
23200
360
0
11200
92
0
0
1500
23.7
12100
4650
91500
23.7
13
40
18.4
200
36
500
7.9
14
6
2.76
0
0
500
7.9
15
00
16
2.88
1000
15.8
16100
46300
540
0
17100
46200
360
0
18150
69150
27001930
13.8305.4002030
13.8
100
1800
N: Nitrogen, TN: Total nitrogen, OFD: Organic Fertilizer Dependence

OFD
(%)

N% (1.086%)
1000
5000
4000
3000
1500
100000
1500
1500
500
500
1000
000
00

10.86
54.3
43.44
32.58
16.29
0.1086
0
000
16.29
16.29
5.43
5.43
10.86
00000

74.46
513.3
170.64143.9848.29
154.1826
28.78
18.99
275
59
131.99
94.99
67.73
16.09
29.54
100
82
96
19.2
31.8

57%
88%
62%
56%
34%
0%
5%
4%
0%
0%
30%
42%
20%
83%
90%
0%0%0%
0%0%

Organic Fertilizer Dependence was calculated based on type of fertilizers, nitrogenconcentration (N%) in fertilizers and amount applied. Average total nitrogen contents for cow
manure were calculated based Maerere et al. (2001), Usman (2013), Sherrian (2016), Huang (2017)and average total nitrogen content for compost were calculated based on Obiamaka (2011),
Sophark T et al. (2012), E-Sayed (2015), Sherrian (2016) and Merlyn (2017). Therefore, organic
fertilizer dependence was classified into 3 categories as ‘not dependent’, ‘moderately dependent’and ‘highly dependent’ at 40%, 30% and 30%, respectively as shown in Table 4.
Table 4 Organic fertilizer dependence categorized
Category

Dependence (%)

Farmer dependence (%)

No dependent

040.0%

Moderately dependent

0-50

30.0%

Highly dependent

50-10030.0%

Correlation Matrix Tree Between Organic Fertilizer Dependence and Soil Properties
The correlation matric tree was used to compare the relationship between organic fertilizer
dependence and soil properties. The results are shown in Figs. 4 and 5.

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IJERD – International Journal of Environmental and Rural Development (2018) 9-1

n= 10, r > 0.631897 significance level *P< 0.05, r > 0.764592 signifivance level **P< 0.01

Fig. 4 Correlation matrix tree between Organic Fertilizer Dependence and soil properties
in Samraong Commune

n= 10, r > 0.631897 significance level *P< 0.05, r > 0.764592 signifivance level **P< 0.01

Fig. 5 Correlation matrix tree between Organic Fertilizer Dependence and soil properties
in Baray Commune
The results of statistical analysis showed that there was no any trend detected between organic
fertilizer dependence and soil properties in Samroang Commune, but in Baray Commune positive
trend was detected between organic fertilizer dependence and soil properties. It can be disused thatthe trend in Samraong Commune was related to the percentage of organic fertilizer dependent, theduration of the application of organic material in farmland and the experience of farmers on
farming practice. Similarly in Baray Commune, the relationship between organic fertilizer
dependence and the soil properties showed a positive correlation. It can be disused that whenfarmer depended more on organic fertilizer input, it leads to increase in soil physical properties
such organic matter and organic carbon and soil chemical properties including EC, K +, Ca2+ andNa+. It was discussed that the application of organic fertilizers can enhanced the accumulation ofsoil organic matter and organic carbon. According to Ebhin Masto et al., (2006), showed that
increased in soil organic matter and soil organic carbon were considerably greater in soil receiving
long-term used of farmyard manure, compost or straw along with inorganic fertilizers. MoreⒸ ISERD140

IJERD – International Journal of Environmental and Rural Development (2018) 9-1

importantly adding only inorganic fertilizers may results in deficiency of other nutrient and decline
in soil physical and chemical properties as the trend was appeared in inorganic fertilizers
dependence. Therefore, the trend become significantly when organic fertilizer has been applied for
10 years in Baray Commune.
CONCLUSIONThe Organic Fertilizer Dependence was a main factor to the impact of soil properties such as soil
physical and chemical properties. In Samraong Commune there was no trend appeared between
Organic Fertilizer Dependence and soil properties, however in Baray Commune the trend wereobvious when organic fertilizer has been applied. This change might related to the percentage ofthe organic fertilizers dependent, the long-term application of organic fertilizers as well as theexperience and knowledge of farmers on farming practice. In addition, due to slowly decompose oforganic fertilizers in the soil, it can be recommended that farmers have to apply more of organic
material on their farmland. When organic fertilizers have been applied for many years the trend
will show clearly on the effectiveness of organic fertilizer on soil properties.
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