IJERD – International Journal of Environmental and Rural Development (2014) 5-1

Research article
erd

Assessment of Economics and Water Productivity of Four
Crops Grown after Wet Season Rice under Differing Water
Availability Conditions in Northeast Thailand
ARUNEE PROMKHAMBUT*
Program on System Approaches in Agriculture, Faculty of Agriculture, Khon Kean University,
Thailand
Email: arunee@kku.ac.th

JOHN S. CALDWELL
Program on System Approaches in Agriculture, Faculty of Agriculture, Khon Kean University,
Thailand

ANAN POLTHANEEProgram on System Approaches in Agriculture, Faculty of Agriculture, Khon Kean University,
ThailandReceived 30 October 2014

Accepted 20 March 2014(*Corresponding Author)

Abstract The economic profitability and water use productivity of four crops grown after
rice harvest were assessed in two sub-districts, Dong Klang (DK) with limited water
availability for irrigation, and Tung Pra (TP) with greater water availability, in Kornsarn
District, Chaiyapoom Province, Northeast Thailand. Three households growing dry season
rice, soybean, chili and field corn were purposively selected for each crop in each area.
Higher crop yields were found in TP than DK for dry season rice, soybean and field corn
(5000 vs 5513 kg/ha, 1646 vs 1971 kg/ha, 3633 vs 4563 kg/ha, respectively), while chili
yield was higher in DK (14917 vs. 9083 kg/ha). Fertilizer cost was the main cost for dry
season rice in both areas (39-42% of total production cost), followed by labor (27-38%),
but irrigation cost was higher in DK than TP (21% and 9%). Seed cost was the main costfor soybean production in DK (43%), but combined harvester was highest in TP (41%).
Labor for fruit picking was the main cost for chili in both areas (80-81%), and fertilizer
was the main cost for field corn (36-53%). Net returns in both areas followed a similar
pattern, chili> dry season rice > soybean ≥ field corn (18,838>1,880>827>598 USD/ha in
DK; 15,462>1,512>540≈ 585 in TP), with higher net returns in TP due to lower costs. The
benefit-cost ratio was highest for dry season rice in both areas; 4.06 and 4.86 in DK andTP, respectively. However, water productivity on a yield basis was lowest for rice in bothareas (0.68 and 0.75 kg/m3 in DK and TP, respectively), and highest for field corn (0.98
and 1.23 kg/m3 in DK and TP, respectively). Measures to reduce water use for rice, andreduce costs and improve market access of other crops could improve water productivity
and farmer income.
Keywords dry season rice, soybean, chili, field corn, benefit-cost ratio, water productivity

INTRODUCTION
Rice is the main economic crop in Northeast Thailand. It contributes one third of the total national
rice planted area and production. However, dry season rice production in the northeast region
covered only 19% of total dry season rice area and contributed only 13% of dry season riceproduction nationally in 2011 (Office of Agricultural Economics, 2012). Dry season rice istypically cultivated with water supplied from large or medium scale reservoirs. Lower rainfall
during the wet season leaves less water in these reservoirs, leading to low yields, crop failures, andreduced income for farmers. Due to the drought in the 2012 wet season, the Office of Agricultural
Economics (2012) has predicted that the harvested area of dry season rice in the Northeast will beⒸ ISERD

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reduced by 50%, resulting in 43% lower yield, in contrast with relatively stable dry season
production in other regions. In years with low levels water in reservoirs, the Royal Irrigation
Department (RID) warns farmers that it may not have sufficient water for late-planted dry season
rice. The Department of Agriculture has promoted change to non-rice crops with lower waterrequirements, but many farmers continue to grow dry season rice. However, the reasons why
farmers continue growing dry season rice have not been reported. In this paper, we focus on
economic returns and water use productivity of rice compared to the most important non-rice crops
as possible key factors in farmer crop choice decision-making. Assessment of these two factors
may suggest possible ways to improve the profitability of non-rice crops.
OBJECTIVE
To compare the economics and water use productivity of 4 different crops grown after wet season
rice under different water availability conditions.
METHODOLOGY
Four crops (dry season rice, soybean, chili and field corn) grown under irrigation after wet season
rice harvesting were assessed based on household surveys in 2 sub-districts, Dongklang (DK) andTungpra (TP), Kornsarn District, Chaiyaphum Province, Northeast Thailand, during 2013. These
sub-districts were selected based on their higher diversity of crops grown after main season rice ina preliminary field survey of 4 sub-districts.
DK was located at a higher elevation and had limited access to irrigation water from small
streams. TP was situated near the Chern River, one of the main rivers in the Northeast. Irrigation
was provided by publicly-financed electric pumps along the river. Soil is finer in TP (Sandy loamy)
than DK (Loamy sand). Rice is the main crop grown in the dry season in both areas.
Three households growing dry season rice, soybean, chili or field corn were purposively
selected for each crop in each area, 12 farmers per sub-district and 24 farmers total. Structured
questionnaires were employed to interview each farmer regarding the farmer’s age and educationlevel, types of dry season crops grown, cultural practices, yields, production costs, prices, markets,and reasons for crop selection. Group interviews with key informants (village headman, village
committee members, and leading farmers) were done to obtain general village information.
Descriptive statistics were calculated using the statistical package SPSS Ver.13.0 (SPSS Inc.).
Spreadsheet software (Microsoft EXCEL) was used for percent analysis.
Water use productivity was expressed on two bases: monetary value per unit cost, shown in Eq.
(1), and yield per quantity of water used, shown in Eq. (2), according to Pereira (2007), as follows:
Value of crops
Irrigation cost

(1)

Crop yield
Total seasonal water use crop(2)

Water cost productivity =Water use productivity =Water requirements for rice (http://www.rid.go.th/attatch_branch/qrice.html) and field corn
(http://www.rid.go.th/attatch_branch/qcorn.html) were obtained from the Royal Irrigation
Department, while the water requirement for soybean was taken from the Agricultural Research
Development Agency (http://www.arda.or.th/kasetinfo/north/plant/soy_water.html).
RESULTS AND DISCUSSION
Farmer Characteristics
Farmer's average ages were similar in both areas (46 years in DK and 48 years in TP). Fifty-eightⒸ ISERD

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percent of respondents in DK had finished elementary school, considerably less than 83% in TP.
The average number of household laborers was 2.33 and 2.00 persons/household in DK and TP,
respectively. These numbers are lower than average number of farm laborers per household of theprovince (2.86) and nationally (2.88) (Office of Agricultural Economics, n.d.).
Table 1 Planted area and yield of crops grown after wet season rice under irrigation in
Dongklang (DK) and Tungpra (TP) sub-districts, Kornsarn Distict, Chaiyaphum
Province, Northeast Thailand
Crops

Dry season rice

SoybeanChili

Field corn

AverageSD
C.V.(%)
AverageSD
C.V.(%)
AverageSD
C.V.(%)
AverageSD
C.V.(%)

Dongklang
Planted area
Yield
(ha/household)(kg/ha)
0.91
5,000
0.24
1,875
27
38
1.97
1,646
1.40
377
71
23
0.45
14,917
0.05
2,097
10
14
0.61
3,633
0.36
1,670
59
46

TungpraPlanted area
Yield
(ha/household)(kg/ha)
0.85
5,513
0.49
642
57
12
0.96
1,971
0.32
104
33
5
0.32
9,083
0.00
1706
0.00
19
0.97
4,563
0.26
1,013
27
22

Source: Field survey, 2013.

Yields and Planted Area of Crops Grown after Wet Season Rice
Higher planted areas per household of each crop except field corn were found in DK compared to
TP (Table 1). This may be due to more labor availability, or because less favorable conditions in
DK leads farmers to expand planted area in order to get more total production despite lower yields.
Yields of dry season rice, soybean and field corn were 10%, 20%, and 26% higher,
respectively, in TP than DK (Table 1). This may be due to more favorable conditions in TP than
DK. However, chili yield was 39% higher in DK than in TP. This is partly due to the longer harvest
period of chili in DK due to its higher elevation. Farmers start growing chili soon after wet season
rice and continue harvesting until rice planting in July for the next wet season in DK, while in TP
farmer's have to stop harvesting chili in June due to excess soil moisture at its lower elevation.
Production Cost of Crops Grown after Wet Season Rice
Both sub-districts had similar patterns of production costs for all four crops. In both sub-districts,
chili production cost was approximately 10 times or more higher than other crops, followed byfield corn and dry season rice, and lowest in soybean (Tables 2 and 3). The fact that the production
cost of soybean was lowest of the four crops contradicted farmer's stated expectations. A higher
share of costs at the start of the season may influence farmer perceptions more than costs later inthe season.
The factors contributing most to production costs differed among the four crops, but thepatterns for each crop were similar between the two sub-districts. Fertilizer was the most important
production cost for rice (42% of total cost in DK, 36% in TP) and field corn (36% in DK, 53% in
TP). The greater proportion of cost allocated to fertilizer in TP indicated that field corn production
was more intensive in TP than in DK, likely reflecting greater water availability in TP. Seed costs
and land preparation were second and third in importance for field corn. More farmers indicatedthat good land preparation is crucial for seed germination. However, combined harvester wassecond in importance in contribution to rice production costs (27% in both DK and TP) (Tables 2
and 3).
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Table 2 Production cost of crops grown after wet season rice under irrigation in Dongklang(DK) Sub-district, Kornsarn Distict, Chaiyaphum Province, Northeast Thailand,2013
Dry season rice

SoybeanChili

Field corn

List
Cost
(USD/ha)
36
208
8
134
2
106

%

Cost
(USD/ha)
1
177
28
153
5
44

%

Cost
(USD/ha)
208
239
526
218
82
6
5,775
169

%

Cost
(USD/ha)
102
104
187
1
14
32
23
54

%

Land preparation
7.3
0.3
2.9
19.7
Seed
43.5
3.3
20.1
Fertilizer
42.1
6.8
7.3
36.1
Fungicide/insecticide
3.0
Crop stimulants
1.1
0.1
Herbicide
1.7
0.1
2.6
Labor
80.0
6.3
Combined harvester
27.0
37.5
Irrigation
21.5
10.7
2.4
10.5
Transportation
0.5
1.2
4.4
to market
Cost of production
495
100.0
407
100.0
7,223
100.0
517
100.0
*Production costs excluding family labor cost. Crop stimulants include plant growth regulators and liquid fertilizer.
USD=US dollars

Table 3 Production costs of crops grown after wet season rice under irrigated area at Tungpra (TP) Sub-district, Kornsarn Distict, Chaiyaphum Province, Northeast Thailand,2013
Dry season rice

SoybeanChili

Field corn

List
Cost
(USD/ha)
64
21
190
2
10
132
24
44

%

Cost
(USD/ha)
6
61
4
6
6
4
21
88
11
58

%

Cost
(USD/ha)
149
233
297
132
7
19
4,194
172

%

Cost
(USD/ha)
64
96
290
54
7
37

%

Land preparation
13.2
2.3
2.9
11.7
Seed
4.4
23.2
4.5
17.6
Fertilizer
39.1
1.6
5.7
52.9
Fungicide/insecticide
0.3
2.1
2.5
Crop stimulants
2.3
0.1
Herbicide
2.1
1.6
0.4
Labor
7.9
80.6
9.8
Combined harvester
27.1
33.1
Irrigation
9.1
21.8
3.3
6.8
Transportation
4.9
4.2
0.0
1.3
to market
Cost of production
487
100.0
265
100.0
5,203
100.0
548 100.0*Production costs excluding family labor cost. Crop stimulants include plant growth regulators and liquid fertilizer.
USD=US dollars

For soybean, seed and combined harvester costs were the two most important costs, with seed
costs higher in DK but combined harvester higher in TP. In DK, farmers did not keep their own
seed for next season, but in TP, one farmer used his own seed produced in an upland area. This
indicates by saving their own seed farmers can lower production costs for soybean. Hired labor cost
comprised approximately 80% of the cost of chili production in both sub-districts (Tables 2 and 3).
The sub-districts differed in the relative importance of irrigation water costs. In DK, with lesswater availability, the highest proportion of production cost spent for irrigation was for rice (21%).
In TP, with greater water availability, the highest proportion spent for irrigation was for soybean(22%) (Tables 2 and 3). Higher water use for soybean in TP was reflected in higher yields (Table1). This indicated that improved access to irrigation water can make non-rice crops more viable..
Returns of Crops Grown after RiceIn both locations, net returns was 10-fold or higher in chili (15,462-18,838 USD/ha), followed bydry season rice (1,512-1,880 USD/ha). In TP soybean was ranked third (827 USD/ha) followed byⒸ ISERD

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and higher yield per area. The high returns of chili were due to its high price (Fig. 1). Nevertheless,using price as the major criteria for crop selection may not be appropriate, due to its greater pricefluctuation as seen in Fig. 1. This may be the reason why farmers did not grow chili as theirsecondary crop, or grew chili as one of 2 or 3 crops.
The benefit-cost ratio (BCR) was highest for dry season rice in both areas, 4.06 and 4.86 in
DK and TP, respectively. This was higher than chili despite its much greater net returns, reflecting
the much lower production cost of rice. Nevertheless, all 4 crops had BCR values higher than 1,
indicating that all crops were profitable for farmers.
However, among the 4 crops chili had the highest water cost productivity, with similar values
in both areas (Table 4). Water cost productivities of the same crop differed between the two subdistricts, reflecting different costs of water. For example, with limited access to water and resulting
higher cost (DK), rice had the lowest value (18.9) of the 4 crops. However, where water costs wereless (TP), water cost productivity was higher (53.5). However, when the cost of water isdisregarded and only the amount of water used is considered, water yield productivity was highest
for field corn, followed by soybean, and lowest for rice in both areas. This finding confirms thatdry season rice uses more water than other crops. Unfortunately, in the absence of data on the waterrequirements of chili, we cannot compare chili water yield productivity.
Table 4 Partial budgeting (USD/ha) of crops grown after wet season rice under irrigated area
at Dongklang (DK) and Tungpra (TP) sub-district, Kornsarn distict, Chaiyaphum
province, northeast Thailand
Dongklang
Dry season
rice
495
2,007
1,512
4.06
18.91

List
Total cost
Gross return
Net return
BCR
Water costproductivity
Water yieldproductivity

0.68

Soybean

Chili

407
946
540
2.33
21.72

7,223
22,685
15,4623.14
133.88

Field
corn
517
1,102
585
2.13
20.25

0.78

NA

0.98

TungpraDry season
rice
487
2,367
1,88
4.86
53.46
0.75

Soybean

Chili

265
1,093
827
4.12
15.73

5,203
24,02818,8384.62
139.80

Field
corn
548
1,147
598
2.09
30.59

0.94

NA

1.23

BCR= Benefit-cost ratio, water cost productivity =yield value (USD)/water yield productivity (USD), water use= crop
yield (kg/area)/total water use (m3/area), NA= not available and USD=US dollars
45
40
35

Price (baht/kg)

30
Rice

25

Field corn

20

Soybean15

Chilli10502002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012

Fig. 1 Farm gate price of crops in this study in Thailand during 2002-2012
Source: Office of Agricultural Economic (n.d.)Ⓒ ISERD

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CONCLUSION
In the introduction to this paper, we indicated that this study sought to answer the question, why do
farmers continue to grow dry season rice despite the problems they faces due to insufficient water
resulting from frequent droughts in the Northeast. Many factors may affect farmer's decisions tocontinuing growing rice. As a first step in identifying which factors are most important in crop
choices, we assessed four dry season crops following wet season rice, dry season rice, soybean,chili, and field corn, using four measures: net returns, BCR, water cost and water use productivity.
Net returns analysis indicated that chili was the most profitable, while dry season rice was secondin net returns, exceeding soybean and field corn in both areas. However, BCR was highest in dry
season rice in both areas compared to chili. The high BCR of rice thus may be the reason why
farmers continue to grow dry season rice. However, in terms of water use efficiency, dry season
rice is not the most efficient crop, and its water cost productivity is poorest when water costs arehigh. Measures to reduce water use in dry season rice in areas with poor water availability, andreduction of production and market constraints for other crops, may enable farmers to obtain higher
water productivity and greater net returns from dry season second crop production. The effect ofthese measures should be assessed in relation to differences among farmer's in levels of educationand household labor availability, those two factors which this study did not evaluate. Developmentof a decision-tree model based on BCR, water availability, and other potential factors could be auseful tool for extension and farmer group leaders.
ACKNOWLEDGEMENTS
This study were financially supported by research fund from Faclty of Agriculture, Khon Kaen
University. Authors are grateful to farmers who kindly participated in the survey and Miss Buppa
Simma and other graduate students for their assistances in data collection.
REFERENCES
Office of Agricultural Economics, 2012. Agricultural statistics of Thailand 2012. (Available fromhttp://www.oae.go.th/download/download_journal/yearbook55.pdf. Accessed: 20 October 2013).
Office of Agricultural Economics. n.d. Household social and economic data and agricultural labor in2010/2011. (Available from http://www.oae.go.th/ewt_news.php?nid=15084. Accessed: 20 October2013).
Pereira, L.S. 2007. Relating water productivity and crop evaporation. In: N. Lamaddalena, M. Shatanawi, M.
Todorovic, C. Bogliotti, R. Albrizio (Eds.), Options Méditerranéennes Ser. B, 57, 31-50.

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