IJERD – International Journal of Environmental and Rural Development (2017) 8-2

Research article
erdUsing Vermitechnology in Soil Rehabilitation for Rice
Production in Salt-affected Area of Northeast Thailand
CHULEEMAS BOONTHAI IWAI*
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
Email: chuleemas1@gmail.com

AJCHARAWADEE KRUAPUKEE
Faculty of Agriculture, Khon Kaen University, Khon Kaen, Thailand
Received 25 January 2017

Accepted 11 November 2017(*Corresponding Author)

Abstract Soil degradation resulting from salinity is a major obstacle to the optimal utilizationof land resources. In Northeast Thailand, approximately 17% of the land is salt-affected due
to salt bearing rocks, predominantly in Nakhon Ratchasima, Khon Kaen, Roi-Et andMahasarakham provinces. The present extent of salt-affected soils in the Northeast alreadysubstantially restricts crop production in many areas especially rice production. This study
aims to study using vermitechnology to rehabilitate saline paddy soil for rice production. The
experiments were conducted to study the influence of earthworm and their activity on soil
properties, production and growth of rice variety (Pathumthani 1) under the influence of salt.
The results found that Activities of earthworms encourage the release of available plant
nutrient, especially when associated with the utilization of organic matters. Applying 1% ofbiochar per 1 kg of dry soil, 650 kg of rice straw per Rai, and 1,000 kg of vermicompost per
Rai can significantly increase organic carbon in soil in deteriorated paddy soil (EC= 0.08 –0.13dS/m), slightly saline paddy soil level 1 (EC= 1.56 – 1.71 dS/m), and moderately saline
paddy soil level 2 (EC= 2.90 – 3.47 dS/m). Moreover, the amount of total nitrogen,exchangeable sodium, exchangeable calcium, and exchangeable magnesium in soil also
increased under all soil salinity level. The experiment under control condition indicated that
activities of earthworms associated with the utilization of biochar, rice straw, and compost
produced by earthworm enhanced the availability of plant nutrients. Furthermore,
earthworms are soil organisms that benefit to soil property rehabilitation such as improving
physical properties of soil by assisting on soil inversion. The burrowing by earthworm
loosens the soil causing well drainage and aeration and improving water holding capacity.
Activities of earthworms associated with the utilization of biochar, rice straw, andvermicompost in different soil salinity level under control condition enhanced growth rate ofrice that increases rice productivity.
Keywords earthworm, rice production, salt-affected area, amelioration

INTRODUCTION
Soil degradation resulting from salinity is a major obstacle to the optimal utilization of land resources.
Salt-affected soils are widely distributed throughout the world, with around 20% of the world's
cultivated land affected (Sumner, 2000). In Northeast Thailand, approximately 17% of the land issalt-affected due to salt bearing rocks (Land Development Department, 1991), predominantly in
Nakhon Ratchasima, Khon Kaen, Roi-Et and Mahasarakham provinces (Department of Mineral
Resources, 1982). The salinization of soils in Northeast Thailand has several unique characteristics,
and has been accelerated by human activities such as improper land management practices,
deforestation, irrigation, salt-making, and construction of roads and reservoirs (Mitsuchi et al., 1986).
All of these human activities except salt-making are believed to promote salinization by causing thelevel of saline groundwater to rise towards the surface. Eventually, low-lying paddy fields become
subject to rapid salinization. The present extent of salt-affected soils in the Northeast alreadysubstantially restricts crop production in many areas. Concerns regarding the potential futureⒸ ISERD

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expansion of areas of salt-affected soils and their effects on land and water resources have beenreported to be one of the most important issues for farmers who live in affected areas (Kohyama andSubhasaram, 1993; Topark-Ngarm, 2010).
Soil salinity has become a serious threat to crop productivity. Many previous studies (Keren,
2000; Levy, 2000; Liang et al., 2003; Sardinha et al., 2003) have reported on the adverse effects ofexcessive amounts of salts on the physical and chemical properties of soils and on plant growth andyield. Salt-affected soils exhibit unique structural problems resulting from soil physical processes
such as slaking, swelling, and dispersion of clay, which in turn cause degradation of soil structure(Boivin et al., 2004; Tejada and Gonzalez, 2005). These structural changes can affect water and air
movement, plant available water holding capacity, root penetration, seedling emergence, and runoff
and erosion, as well as tillage and sowing operations (Oster and Jayawardane, 1998). Salinity also
affects soil chemical properties through the presence of high soluble salt concentrations (Sumner,
2000). This alters the osmotic and matric potential of the soil solution, thereby adversely affecting
soil microbial communities and their activity (Zahran, 1997; Sardinha et al., 2003; Rietz and Haynes,
2003). This in turn can have a negative influence on plant growth and yield (Marschner, 1995). In
addition, changes in the proportions of exchangeable ions in the soil solution have osmotic and ionspecific effects that can produce imbalances in plant nutrients, including deficiencies of several
nutrients, or conversely high levels of Na+ (Grattan and Grieve, 1999; Mengel and Kirkby, 2001).
In order to solve such problems, expansion of amelioration actions and improved management
practices are needed to reclaim salt-affected soils (Qadir et al., 2001; Suarez, 2001; Barrett-Lennard,2002).
The amelioration of salt-affected soils can be accomplished through many effective methods,
such as water leaching, chemical remediation, and phytoremediation (Sharma and Minhas, 2005;
Qadir et al., 2007). The amelioration of salt-affected soils using chemical agents, including gypsum,
calcite, calcium chloride and organic matter (farmyard manure, green manure, organic amendments,and municipal solid waste), is a successful approach that has been implemented worldwide (Mitchell
et al., 2000; Hanay et al., 2004; Sharma and Minhas, 2005; Tejada et al., 2006). According to Melero
et al. (2007), the application of organic matter conditioners has become a common practice in saltaffected areas in the last several decades and constitutes an important method of soil regenerationand fertility enhancement. The application of organic matter for soil remediation is consideredessential for sustainable land use and crop productivity.
Vermitechnology has been developed as a means of using earthworm converting wastes intovalue-added products which can be utilized for improving soil structure and fertility. Agro wastes
could effectively be tapped for resource recovery through vermicomposting technology to produce a
product for use in land rehabilitation. Adding compost or vermicompost to soils can help to replenish
soil organic carbon which can help to improve soil health and promote further primary productivity(Iwai et al., 2010; 2011; Lal, 2004;).
Earthworms are known to have beneficial effects on the physical, chemical and biologicalproperties of soils, and thereby contribute to increased plant growth and crop yields in both naturaland managed ecosystems (Edwards and Bohlen, 1996; Edwards, 1998). Their beneficial effects havebeen attributed to improvements in soil properties and structure, greater availability of mineral
nutrients to plants (Gilot, 1997), and enhanced microbial populations and activity, thereby producing
biologically active metabolites such as plant growth regulators (Doube et al., 1997).
OBJECTIVE
The objective of this study was to investigate the effectiveness of vermitechnology for alleviatingsalt-affected soils, and to determine the effect of these amendments on the rice production in
Northeast of Thailand.
METHODOLOGY
Preparation of Soil and VermicompostⒸ ISERD

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An experiment was carried out to investigate the effects of vermicompost produced on soil propertiesof different level of saline soils on the growth of rice under greenhouse conditions at Khon Kaen
University, Thailand, during the rainy season of 2015. The soil was air-dried and passed through a 2
mm mesh to remove stones and other debris. The initial physical and chemical properties of the soils
before the start of the experiment are shown in Table 1. Vermicompost were prepared in a laboratoryof the Land Resources and Environment Department, Faculty of Agriculture, Khon Kaen University.
They were produced from cassava waste materials incubated for two months in black plastic pots.
The earthworm species used to produce the vermicompost was Eudrilus eugeniae. The chemical
properties of the vermicompost used are shown in Table 1.
Table 1 Chemical characteristic of soil, biochar and vermicompost used for experiments
Parameter
Soil texture
Sand (%)
Silt (%)
Clay (%)
OM (%)EC (dS/m)
pH (1:5)
Total N (%)
Extractable P (ppm)
Exchangeable K+ (ppm)
Exchangeable Na+ (ppm)
Exchangeable Ca2+ (ppm)
Exchangeable Mg2+ (ppm)

Soil
loam
49.9
38.1
12.0
0.63
0.09
6.32
0.059
2.94
56.14
48.89
930.9081.38

Biochar
16.40
2.85
6.34
0.16
2,543.53
5,886.65
113.453,084.95
669.86

Vermicompost
8.37
2.20
6.84
0.77
2,309.52
7,683.94
142.34
13,675.76
1,992.63

Experimental Design
The experiments were conducted to study the influence of earthworm and their activity on soil
properties, production and growth of rice variety (Pathumthani 1) under the influence of salt. The
experiment was laid out in a completely randomized design (CRD) with three replications. Threelevel of saline soils were used, in deteriorated paddy soil (EC= 0.08 – 0.13dS/m), slightly saline
paddy soil level 1 (EC= 1.56 – 1.71 dS/m), and moderately saline paddy soil level 2 (EC= 2.90 –3.47 dS/m). Seven treatments were compared: T1 = control; T2 = biochar (BC1%); T3 = biochar(BC1%)+earthworms (20 individuals pot-1); T4 = rice straw 650 kg/rai; T5 = rice straw 650
kg/rai)+earthworms (20 individuals pot-1); T6 = vermicompost (VMC) 1,000 kg/rai; T6 =earthworms (20 individuals pot-1). Seven kilograms of 2 mm sieved air-dried soil were placed ineach black plastic pot of 30 cm height and 25 cm diameter for each treatment.
Table 2 The results of vermitechnology with different amendments on Rice production in
deteriorated paddy soil (EC= 0.08 – 0.13 dS/m)
Treatments

Spikelet
Yield (kg./Rai)
1000 grain weight (g)numberSoil
12.33
816.00 ab
25.40 absoil add earthworm (EW)
13.67
849.20 ab
26.87 asoil add biochar (BC)11.33
705.10 bc
25.90 asoil add BC and EW
14.33
1,000.51 a
26.77 asoil add rice straw
12.00
512.09 c
23.33 bsoil add rice straw and EW
13.33
599.47 bc
26.23 asoil add vermicompost (VMC)
14.67
817.12 ab26.37 asoil add VMC and EW
16.00
1,024.38 a
27.17 af-test
ns
**
**
CV %
20.18
14.27
4.04
Note: Values are mean ± standard deviation. Means with the same letter in the same column are not significantly different(P>0.05)Ⓒ ISERD

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Table 3 Results of vermitechnology with different amendments on Rice production in slightly
saline paddy soil level 1 (EC= 1.56 – 1.71 dS/m)
Treatments
Soil
soil add earthworm (EW)
soil add biochar (BC)soil add BC and EW
soil add rice straw
soil add rice straw and EW
soil add vermicompost (VMC)
soil add VMC and EW
f-testCV %Spikeletnumber
7.33
8.67
6.33
9.33
7.00
8.33
9.67
11.00
ns
32.11

Yield (kg./Rai)

1000 grain weight (g)496.00 bc
593.90 abc
482.85 bc
751.44 ab385.21 c
635.48 abc
763.06 ab
878.00 a
**
21.06

24.60
26.30
25.30
26.43
23.80
26.53
26.67
27.07
ns
5.02

Note: Values are mean ± standard deviation. Means with the same letter in the same column are not significantly different(P>0.05)

Plant Data Collection
The growth and rice production were measured.
Soil Analyses
Triplicate soil samples were collected at a depth of 0–10 cm by taking a soil core from each pot at
the end of the experiment. The soil samples were analyzed for soil physical and chemical properties
at the laboratory of the Land Resources and Environment section, Faculty of Agriculture, Khon Kaen
University. Soil texture was determined by a hydrometer (Bouyoucos, 1951). Soil pH wasdetermined in a 1:2.5 soil to water solution by a pH meter. Electrical conductivity (ECe) in saturated
paste extracts was measured following the method described by the United States Department ofAgriculture (USDA, 1954). Cation exchange capacity (CEC) was determined by the 1 N ammonium
acetate method (Black, 1965), and total soil organic carbon (SOC) was determined by the method ofWalkley and Black (1934). Total nitrogen (TN) was measured by the Kjeldahl method (Bremner,
1960). Extractable phosphorus (Extr. P) was determined by the Bray II method (Bray and Kurtz,
1945). Exchangeable potassium (Exch. K+), sodium (Exch. Na+), calcium (Exch. Ca2+) andmagnesium (Exch. Mg2+) were extracted with 1 N ammonium acetate (pH 7.0) (Schollerger andSimmon, 1945). The concentrations of K+ and Na+ from these extracts were analyzed by flame
photometry, while those of Ca2+ and Mg2+ were analyzed by atomic absorption spectrometry
following a standard procedure.
Statistical Analysis
The data collected were analyzed statistically using analysis of variance (ANOVA) techniques.
Treatment means were compared by the Least Significant Difference (LSD) method at the 5% level.
All data analysis was done using Statistix 8.0 (Analytical Software, 2003).
RESULTS AND DISCUSSION
The results found that Activities of earthworms encourage the release of available plant nutrient,
especially when associated with the utilization of organic matters. Applying 1% of biochar per 1 kgof dry soil, 650 kg of rice straw per Rai, and 1,000 kg of vermicompost per Rai can significantly
increase organic carbon in soil in deteriorated paddy soil (EC= 0.08 – 0.13dS/m), slightly saline
paddy soil level 1 (EC= 1.56 – 1.71 dS/m), and moderately saline paddy soil level 2 (EC= 2.90 –3.47 dS/m). Moreover, the amount of total nitrogen, exchangeable sodium, exchangeable calcium,and exchangeable magnesium in soil also increased under all soil salinity level. The experiment underⒸ ISERD

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control condition indicated that activities of earthworms associated with the utilization of biochar,rice straw, and compost produced by earthworm enhanced the availability of plant nutrients.
Table 4 The results of vermitechnology with different amendments on Rice production inmoderately saline paddy soil level 2 (EC= 2.90 – 3.47 dS/m)
Treatments
Soil
soil add earthworm (EW)
soil add biochar (BC)soil add BC and EW
soil add rice straw
soil add rice straw and EW
soil add vermicompost (VMC)
soil add VMC and EW
f-testCV %Spikeletnumber
5.33
6.67
4.33
6.67
5.00
5.00
6.33
8.00
ns
37.63

Yield (kg./Rai)

1000 grain weight (g)314.56460.41457.14480.00400.54459.32521.36535.51
ns
18.41

22.50
23.90
23.37
23.57
23.07
23.43
23.20
24.53
ns
3.44

Note: Values are mean ± standard deviation. Means with the same letter in the same column are not significantly different(P>0.05)

CONCLUSION
The above results showed the beneficial effects of earthworm and vermicompost application inincreasing the rice growth and production. The results of soil analysis showed that application ofvermicompost significantly increased soil organic carbon, CEC and soil N, P and K contents. Organic
amendments can thus serve as a source of essential nutrients for plants as well as contributing to
improved soil properties. In addition, these amendments increased exchangeable K+, Ca2+ andMg2+ while decreasing exchangeable Na+ in the saline soil, thereby reducing soil salinity. These
results suggest that the use of earthworm and vermicompost is likely to be helpful for both alleviating
salinity and improving crop productivity in salt-affected areas. The addition of earthworms as soil
conditioners can also contribute to improved physical, chemical and biological properties of the soil
and thereby increase its nutritive value for plants.
ACKNOWLEDGEMENTS
The author thanks the Integrated Water Resource Management Research and Development Centerin Northeast Thailand and The Research Developing and Learning Centre on Earthworm for
Agriculture and Environment, Khon Kaen University and Khon Kaen Research Fund on the research
project “Using Agro-industrial Waste with Chicken manure in Vermicomposting for Soil
Rehabilitation and Rice Productivity”.
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