IJERD – International Journal of Environmental and Rural Development (2013) 4-2

Research article
erd

Water Footprint of Energy Crops under the Rain-Fed andIrrigated Cultivation in Eastern Thailand
SANIDDA TIEWTOY*Rajamangala University of Technology Thanyaburi, Pathum Thani, Thailand
Email: saniddatiewtoy@hotmail.com

THANUTYOT SOMJAIKing Mongkut's University of Technology North Bangkok, Prachinburi, Thailand

CHALITA SUWANKing Mongkut's University of Technology North Bangkok, Prachinburi, Thailand
Received 13 December 2012

Accepted 10 June 2013(*Corresponding Author)

Abstract Under the current 15-year Renewable Energy Development Plan (REDP) of
2008-2022, Thailand’s Ministry of Energy promotes the production and use of ethanol tosubstitute fossil oil. Two major crops used to produce ethanol in Thailand are sugarcaneand cassava. This research assesses the water footprint (WF) of sugarcane and cassava
under the rain-fed and irrigated agriculture in the eastern provinces of the Kingdom. The
data on crop evapotranspiration, use of fertilizer, and yield are required for the estimationof the water footprint in crop production, the approach of which is based on The Water
Footprint Assessment Manual of Hoekstra et al. The results of this study show that theaverage WF’s of sugarcane in rain-fed and irrigated cultivation are respectively 171 m3/ton(89% green, 11% grey) and 162 m3/ton (83% green, 7% blue, 10% grey). For cassava, theaverage WF’s in rain-fed and irrigated agriculture are 387 m3/ton (85% green, 15% grey )and 413 m3/ton (81% green, 5% blue, 14% grey), respectively. Rainfall is still a key factor
in the cultivation of sugarcane and cassava taking into consideration the proportion ofwater use. The sugarcane yield in the rain-fed fields is lower than that in the irrigatedfields, while the yield of cassava in both environments is similar. The findings not merely
would be of use to stakeholders and policymakers for better water management but also
could be used as basis data of sub-national water footprint for crop production.
Keywords water footprint, sugarcane, cassava, energy crops, Thailand

INTRODUCTION
Ministry of Energy of Thailand , has since 2008 implemented the current 15-year Renewable
Energy Development Plan (REDP 2008-2022) with the goal to increase renewable energy use to20% of the total energy consumption by 2022. In addition, the present government, to expedite therealization of the REDP, has tasked the Energy Ministry with the drawing up of the Renewable andAlternative Energy Development Plan (AEDP 2012-2021) to identify the framework and directionof Thailand’s renewable energy development. Encouraging collaboration among the community
people in greater production and use of renewable energy is one of six strategies to promote AEDP.
The target of ethanol production output is 9 Ml/day by 2021 through improvement of averageyields of sugarcane and cassava to not less than 15 and 5 t/rai/yr (6.25 rai=1 ha). Moreover, otheralternative energy crops such as sweet sorghum are promoted.
Based on the aforementioned policies, the data on the amount of water consumption isimportant for policymakers in the promotion of ethanol production and use. In this regard, the aimof this research is to assess the water footprint (WF) of sugarcane and cassava under the rain-fed
and irrigated agriculture in the eastern part of Thailand.

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METHODOLOGY
Study area: The eastern region is an important cultivation area of fruits, maize, sugarcane andcassava. Provinces of Chachoengsao, Chonburi, Prachinburi and Sakaeo (i.e., 4 out of 7) wereselected as the study area (Figure 1).

Selected provinces

Fig.1 Ethanol plants in Thailand and study area
Source: (DEDE, 2008)

Research methodology: Calculation of water footprint of sugarcane and cassava under the rain-fed
and irrigated conditions in this research follows the Water Footprint Assessment Manual ofHoekstra et al. (2011). The data on crop evapotranspiration, use of fertilizer, and yield are
requisites for the estimation of the water footprint in crop production.
The water footprint concept: Water footprint (WF) is an indicator of freshwater use that takes
into account both direct and indirect water use of a consumer or producer. It consists of threecomponents: green, blue, and grey water footprints. The green water footprint is the volume ofrainwater consumed during the production process, the blue water footprint refers to consumptionof natural water resources (surface and groundwater) along the supply chain of a product, and thegrey water footprint is defined as the volume of freshwater required to assimilate the load ofpollutants to meet the water quality standards (Hoekstra et al., 2011).
Calculation of green and blue water footprint: Green and blue water evapotranspiration duringcrop growth can be estimated with CROPWAT 8.0 model based on the Food and Agriculture
Organization (FAO, 2009). According to Hoekstra et al. (2011), this research selects the irrigation
schedule option to determine the crop evapotranspiration. The calculated evapotranspiration iscalled ETa, which is calculated as the crop evapotranspiration under optimal conditions (ET c) times
a water stress coefficient (Ks) as shown below:
ETa = Ks × ETc= Ks × Kc × ETo(1)Where ETa is the actual crop evapotranspiration, ETC the crop evapotranspiration, ETo thereference evapotranspiration, Kc the crop coefficient, and Ks a water stress coefficient with a value
between 0 and 1.
The green and blue components of crop water use (CWU) are calculated by accumulation ofdaily evapotranspiration over the complete growing period. The total ET green and ETblue in mm areconverted to crop water use in m3/ha by a factor 10.

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Calculation of the green, blue and grey water footprint for crop production: Calculations ofthe water footprint (WF) of crop growing process are shown in Eq. (2) and (3). The total water
footprint of the crop growing process is the sum of the green, blue, and grey components as shownin Eq.(5).
WFproc,green =CWU green(2)Y

WFproc,blue = CWU blueYWFproc,grey =(3)(  AR) /( cmax  cnat )Y(4)WF proc = WFproc,green+ WFproc,blue+ WFproc,grey(5)

Where CWU is crop water use (m3/ha), Y crop yield (ton/ha), α leaching-run-off fraction (%),
AR chemical application rate (kg/ha), Cmax the maximum acceptable concentration (kg/m3), andCnat the natural concentration for the pollutant considered (kg/m3).
Data collection: Primary and secondary data were obtained from various sources. Primary data
were collected using interviews and questionnaires while secondary data, such as land use map,climatic data, soil type etc., were taken from reports and publications. Additional details about themethods used in this study are indicated below:
Climate data: The climate data for a 30-year period (1981-2010) were taken from the Thai
Meteorological Department.
Soil types: Based on the Land Development, Department classification, soil types are mostly sandy
loam suitable for cassava and sugarcane production.
Crop parameter: Farmers from the four selected provinces were interviewed with the questions
from the questionnaire. Data on household size, age structure, water source for crop production,
cropping pattern, crop yield, and fertilizer application were part of the questionnaire.
Ambient water quality standard: Based on the Notification of the National Environment Board
No. 8, the maximum acceptable concentration for nitrate in surface water quality standards is 5
mg/l.
Crop coefficient (kc): Crop coefficients of sugarcane and cassava were taken from the Royal
Irrigation Department (RID, 2010).
RESULTS AND DISCUSSIONS
Calculation of green and blue WF under the rain-fed and irrigated conditions in this research
employed irrigation scheduling based on actual water use from field survey. In the case of irrigatedcondition, irrigation schedule option of without irrigation was used to determine the water use bycrop. The sugarcane yield in the rain-fed fields is lower than that in the irrigated fields, while theyield of cassava in both conditions is similar. The outputs of sugarcane and cassava for rain-fed andirrigated conditions are respectively shown in Tables 1 and 2.
The grey WF is estimated based on the application of nitrogen fertilizer to crops. The averagenitrogen fertilizers applied to sugarcane and cassava are 66.21 and 68.23 kg/ha, respectively. The
leaching run off fraction is assumed at 10% of the application rate (Chapagain et al., 2006). Due tosurface quality standards (DEQP, 1994), the maximum allowable concentration is 5 mg/l. The
natural concentration in the receiving water body is assumed to be zero. The grey WF is calculated
based on Eq.(4). The outputs of the grey WF of sugarcane and cassava for rain-fed and irrigatedconditions are respectively shown in Tables 3 and 4.

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Table 1 Components of green and blue water footprint for sugarcane production
Province
Rain-fed
Chonburi
Prachinburi
SakaeoIrrigated
Chonburi
Prachinburi
SakaeoETgreen(mm)

ETblue
(mm)

ETa
(mm)

CWUgreen(m3/h)

CWUblue(m3/h)CWUtotal(m3/ha)Y(ton/ha)WFproc,green(m3/ton)WFproc,blue(m3/ton)944.4
1105.71111.2

0.0
0.0
0.0

944.4
1105.71111.2

9444
11057
11112

0.0
0.0
0.0

944411057
11112

70.0
65.9
70.6

134.9
167.7
157.3

0.0
0.0
0.0

944.4
1105.71111.2

280.5
46.0
2.2

1224.91115.31113.4

9444
11057
11112

2805
460
22

12249
11153
11134

96.9
70.3
72.3

97.5
157.4
153.4

29.0
1.4
0.3

Table 2 Components of green and blue water footprint for cassava production
Province
Rain-fed
Chonburi
Prachinburi
SakaeoChachoengsao
Irrigated
Chonburi
Prachinburi
SakaeoChachoengsao

ETgreen(mm)

ETblue
(mm)

ETa
(mm)

CWUgreen(m3/ha)CWUblue(m3/ha)CWUtotal(m3/ha)Y(ton/ha)WFproc,green(m3/ton)WFproc,blue(m3/ton)

832.5
709.2
773.3
742.8

0.0
0.0
0.0
0.0

832.5
709.2
773.3
742.8

8325
7092
7733
7428

0.0
0.0
0.0
0.0

8325
7092
7733
7428

25.0
23.3
25.0
20.3

333.0
305.0
309.3
396.0

0.0
0.0
0.0
0.0

832.5
709.2
773.3
742.8

33.6
129.1
35.5
24.9

866.1
838.3
808.8
767.7

8325
7092
7733
7428

336
1291
355
249

8661
8383
8088
7677

24.9
23.7
25.1
19.5

333.8299.4
308.5
394.0

13.5
54.5
14.2
13.0

Table 3 Water footprint of sugarcane production in Eastern Thailand
Province
Chonburi
Prachinburi
SakaeoAverage

WFgreen
134.9
167.7
157.3
153.31Rain-fed (m3/ton)
WFblue
WFgrey
0.0
18.0
0.0
22.3
0.0
14.2
0.0
18.17

WFtotal
152.9
190.0
171.5
171.48

WFgreen
97.5
157.4
153.7
136.18Irrigated (m3/ton)
WFblue
WFgrey
29.0
13.0
1.4
20.9
0.3
13.8
10.21
15.90

WFtotal
139.4
179.7
167.8
162.29

Table 4 Water footprint of cassava production in Eastern Thailand
Province
Chonburi
Prachinburi
SakaeoChachoengsao
Average

WFgreen
333.0
305.0
309.3
396.0
335.8

Rain-fed (m3/ton)
WFblue
WFgrey
0.0
61.6
0.0
58.3
0.0
53.9
0.0
60.1
0.0
58.5

WFproc
394.6
363.4
363.2
426.0
386.8

WFgreen
333.8
299.4
308.5
394.0
393.9

Irrigated (m3/ton)
WFblue
WFgrey
13.5
61.8
54.5
57.3
14.2
53.8
13.0
62.6
23.8
58.9

WFproc
409.1
411.2
376.5
456.0
413.2

Table 5 Comparison of this study result, Mekonnen and Hoekstra’s (2011) and global
average water footprint
Area/Farming system
Eastern Thailand
Rain-fed
Irrigated
Mekonnen andHoekstra (2011)
Rain-fed
Irrigated
Global Average

WFgreen

Sugarcane (m3/ton)
WFblue
WFgreyWFproc

WFgreenCassava (m3/ton)
WFblue
WFgreyWFproc

153
136

010

18
16

171
162

336
334

0
24

56
59

387
413

164
120
139

0
104
57

13
1413

176
238
210

550

013564The estimated total water footprint of crop production process (WFproc) is the summation ofthe green, blue, and grey water footprint as Eq.(5). The water footprints of sugarcane and cassava
production in eastern Thailand under rain-fed and irrigated agriculture are illustrated in Tables 3-4.
The results show that the average WF’s of sugarcane in rain-fed and irrigated cultivation are
171.48 m3/ton and 162.29 m3/ton, respectively. For cassava, the average WF’s in rain-fed andirrigated agriculture are 386.8 m3/ton and 413.2 m3/ton, respectively.

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As shown in Table 5, water footprint of sugarcane of eastern Thailand of the irrigatedcondition (162) is lower than that of rain-fed (171), those of rain-fed (176) and irrigated cultivation(238) of Mekonnen and Hoekstra, and that of global average (210). In the same table, water
footprints of cassava of eastern Thailand (387 and 413 for rain-fed and irrigated respectively) arelower than that of global average (564).
CONCLUSION
This paper deals with the assessment of water footprint (WF) of sugarcane and cassava under therain-fed and irrigated agriculture in the eastern part of Thailand. The results show that the average
WF’s of sugarcane in rain-fed and irrigated cultivation are 171 m3/ton (89% green, 11% grey) and
162 m3/ton (83% green, 7% blue, 10% grey), respectively. For cassava, the average WF’s in rainfed and irrigated agriculture are 387 m3/ton (85% green, 15% grey) and 413 m3/ton (81% green,5% blue, 14% grey), respectively. The average WF of sugarcane in rain-fed is higher than that in
irrigated agriculture because the rain-fed yield is lower than the irrigated yield. The yields ofcassava in both conditions are very similar, but crop water use of irrigated cassava is higher thanrain-fed cassava, thereby leading to the lower average WF of cassava in rain-fed than in irrigatedagriculture. With the proportion of water use taken into account, rainfall remains a key factor in thecultivation of sugarcane and cassava. The WF reduction in the eastern region is achievable throughadoption of part or all of the following suggestions in combination: 1) increase yield throughimproved agricultural practice; 2) improve the irrigation schedule by optimizing timing andvolumes of application; 3) support investments in irrigation systems and techniques that conservewater; and 4) reduce the use of chemical fertilizers, pesticides and insecticides. The findings of thisstudy not only would be of great use to both stakeholders and policymakers for better water
management but also could be further used as basis data of sub-national water footprint for crop
production.
ACKNOWLEDGMENTS
The authors would like to express deep gratitude and sincere appreciation to the National ResearchCouncil of Thailand for the financial support.
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