Technologies for Efficient Use of Irrigation Water and Energy in China

Available online at www.sciencedirect.comJournal of Integrative Agriculture2013, 12(8): 1363- 1370心ScienceDirectAugust 2013RESEARCH ARTICLETechnologies for Efficient Use of Irrigation Water and Energy in ChinaZHANG Qing-taol, XIA Qing, Clark C K Liu2 and Shu Geng1.31 Key Laboratory for Urban Habitat Environmental Science and Technology, School of Environment and Energy, Peking UniversityShenzhen Graduate School, Shenzhen 518055, P.R.China2 Department of Civil and Environmental Engineering, University of Hawaii at Manoa, Honolulu 96822, USA3 Department of Plant Sciences, University of Califormia, Davis, CA 95616, USAAbstractWhile the shortage of water and energy is a well-recognized worldwide natural resources issue, lttle attention has beengiven to irrigation energy efficiency. In this paper, we examine the potential energy savings that can be achieved byimplementing improved irrigation technologies in China. The use of improved irigation management measures such as aflow meter, irrigation scheduling, and/or regular maintenance and upgrades, typically reduces the amount of water pumpedover the course of a growing season. The total energy saved by applying these improved measures could reach 20%, ascompared with traditional irrigation methods. Two methods of imigation water conveyance by traditional earth canal andlow pressure pipeline irrigation (LPPD) were also evaluated. Our study indicated that LPPI could save 6.48x109 kWh yr1when applied to 11 Chinese provinces. Also, the CO2 emission was reduced by 6.72 metric tons per year. Among these 11surveyed provinces, the energy saving potential for two provinces, Hebei and Shandong, could reach 1.45x109 kWh yrl.Using LPPI, potential energy saved and CO2 emissions reduced in the other 20 Chinese provinces were estimated at about2.97x109 kWh yr:1 and 2.69 metric tons per year, respectively. The energy saving potential for Heilongjiang, a majoragriculture province, could reach 1.77x109 kWh yr'l, which is the largest in all provinces. If LPPI is applied to the entirecountry, average annual energy saving of more than 9 billion kWh and average annual CO2 emission reduction of morethan 9.0 metric tons could be realized. Rice is one of the largest users of the world's fresh water resources. Compared withcontinuous flooding irmigation, intermittent imigation (IT) can improve yield and water-use efficiency in paddy fields. Thetotal increments of net output energy and yield by ITI in paddy fields across China could reach 2.5x1016 calories and107 tons, respectively. So far only a small part of agricultural land in China has adopted water and energy savingtechnologies. Therefore, potential water and energy savings in China by adapting improved irigation technology couldbe significant and should be carefully studied and applied.Key words: water and energy efficiency, irigation management, low pressure pipeline irigation, energy saving potential,intermittent irrigationduction practices rely heavily upon the use of fertilizerINTRODUCTIONand irigation. These inputs have led to a dramatic in-crease in fossil fuel consumption and raised seriousWater and energy are inextricably intertwined naturalconcerns over sustainable use of energy resourcesresources (Schnoor 2011). Modern agriculture pro- (Hulsbergen et al. 2001; Deike et al.2008). Pimentel中国煤化工Received 17 October, 2012 Accepted 10 January, 2013CNM HGCorrespondence Shu Geng, Tel: +86-755-26032802. Fax: +86-755-26032078, E-mail: gengxu @ pkusz.edu..MYH62013.CAAS.. AII nghs reserved. Publishedby ElsevierLtd.do1:101016/52095311913)6054441364ZHANG Qing-tao et al.et al. (1973, 2002 a, b), Pimentel and Pimentel (2003),for about 62% of total freshwater use in China (MinistryNaylor (1996) and Deike et al. (2008) have warnedof Water Resources 2009). Faced with a severe waterthat dependency on fossil fuels will be a potential threatand energy shortage, the Chinese government has rec-to the growth and stability of world food production.ognized the importance of a better understanding ofTherefore, there has been increasing interest in inte-these shortages and their inter-relationship and the im-grating and designing efficient energy and water sys-portance of developing and implementing an integrativetems (Siddiqi and Anadon 2011).water and energy management policy (Fredrich andProblems of declining reliability of water supply asDavid 2008). With rapidly growing populations, it isa result of climate change and climate variability, ascritically important to sustain high productivity and yieldswell as increased costs of water application, whichthrough improved water productivity. In the long run,may partly be caused by deep groundwater pumping,investments to boost water productivity and improveare negatively impacting farmers' incomes (Pimentelenergy-use efficiency in crop production are two path-et al. 2002b; Bhuyan 2004). Qiu et al. (2012) foundways to reduce energy dependency, enhance naturalthat the widely spreading aridity in Northern China isresource sustainability and ensure future food securitybeing caused by both extensive land-use and rapid cli- (Mushtaq et al.2009).mate change. It is estimated that in Saudi Arabia up toThe principal objective of this paper is to examine9% of its total annual electrical energy consumptionwater and energy consumption in China and potentialis used for ground water pumping and water desalina-gains by using improved irrigation technologies.tion (Siddiqi and Anadon 2011). Previous studies onenergy consumption by food production activities in-RESULTS AND DISCUSSIONdicated that irrigation consumes a greater amount ofenergy than other farm activities (Mittal and Dhawan1989; Peart et al. 1995; Mrini et al. 2001). Further,Water and energysavingunderimprovedimrigationthe major share of energy consumption by irrigationmanagement measuresis supplied by nonrenewable fossil energy (Mittal andDhawan 1989; Mrini et al. 2001; Topak et al. 2005).The use of a flow meter, irrigation scheduling, and/orMittal and Dhawan (1989) conducted a study on irri- regular maintenance and upgrades typically can reducegation energy consumption using different types ofthe amount of water pumped over the course of a grow-surface irigation systems, including basin, flow, and ing season. The total energy saved by applying thesefurrow irrigation. They reported that irrigation op-improved management measures could reach 20%, as .eration required about 35-50% of total energy inputcompared with traditional irigation methods (Table 1). .or growing field crops depending on the type of irri-The energy saving under these improved managementgation system being used. Singh et al. (2002) foundmeasures could reach 3.2x108 kWh on state-ownedthat in an arid region in India, irrigation accounts forfarms in China over the course of a growing seasonmost of the on-farm energy consumption. They sug-(Table 1).gested that the energy-intensive demands of variousResults in Table 1 were derived based on the follow-crops should be factored into management decisionsing assumptions: Cost should be estimated if a flowwhen determining the most appropriate crops for a meter is used. Irrigation water must be measured if itgiven production system. These findings indicatedis to be used efficiently. Measurement often results inthat energy input for irigation is a limiting factor for a decision to use less water. Water must be measuredproduction in arid and semi-arid regions (Topak et al. in each field and set for optimum irrigation water2005). While water and energy shortage is a well- management. A measurement at the diversion, lateral-,recognized worldw ide natural resources issue, litleor farm-delivery point can be translated to each field ifattention has been given to water and energy nexus,the water is not split and used on separate fields. Mostespecially irrigation energy efficiency.water-measurin中国煤化工f flow, whichAgricultural water use, mainly for irigation, accounts is converted toMHcNMHGAnirigator⑥2013, CAAS. Alights reseved. Published by EsevierLtd.Technologies for Efficient Use of Irrigation Water and Energy in China1365Table 1 Water and energy saving under improved rrigation management measures on state-owned farms in Chinal)Current water use Seasonal irigation system water or energy-use Energy useEnergy cost analysisDescription(x10 m2)analysis reduction in water usage (x10* m)(x109 kWh)__ water or energy saving (%)Chinese system today7.611.5Add flow meter7.095.151.466.77Add irigation scheduling6.976.331.43 :8.32Add maintenance and upgrades1.43Add flow meter and irigation scheduling6.0615.4220.28 .and maintenance and upgrades) Calculated by an irigation management model. The model cited from Energy Consumption Awareness Tool for Irigation, United States Department of AgricultureNatural Resources Conservation Service (NRCS).needs to know how many acre-feet or acre-inches of口2008water are being applied to a field of known area.口2009Cost should also be estimated if irrigation schedul-2.5一。ing is used. Irrigation scheduling is deciding when2.0一and how much irrigation water to apply. The soilmoisture deficit in the root zone need be measured in1.0- |order to design an effective management system.0.5 -00川0.0 +Farmers use a number of irrigation scheduling meth-North NorthEastMiddle South South NorthChina East China China China West Westods that consider soil type, soil water storage capacity,crop growth stage, water availability, and level of iri-gator control. Scheduling generally involves monitor-Fig. Effective irigation area in China. Source of original data:ing plant available soil moisture, estimating current cropNBSC, 2011.water use, and anticipating future crop water use dur-ing the scheduling period. Tools commonly used inpotential energy saving by LPPI, and emissions re-scheduling include visual and or thermal monitoringduction by LPPI.systems of crop conditions, soil moisture sensingAs shown in Table 2, potential energy saving and thedevices, rainfall monitoring, media evapotranspirationreduction of greenhouse gas emissions under LPPI in(ET) reports, local crop ET networks, and commer-the 11 surveyed provinces are about 6.48x109 kWh yrlcial scheduling services.and 6.72 Mt CO,e yrl. The energy conservation po-tential for Hebei and Shandong provinces alone is aboutWater and energy saving under low pressure1.45x109 kWh yr!.pipeline irigation (LPPI)Potential energy saving under LPPI in the 20 non-surveyed provinces in China was indicated in Table 3.Fig. shows the effective irrigation area in China. Mid-Potential energy saving and emissions reduction underChina has the largest irigation area, while South ChinaLPPI in the 20 non-surveyed provinces could reachhas the smallest. The average cost of irigation en-2.97x109 kWh yrl and 2.69 Mt CO,e yr-. The energyergy consumption for wheat in China is about 360conservation potential for Heilongjiang could be moreCNY ha-, which accounts for 5% of the total cultiva-than 1.77x109 kWh yr', which is the largest in alltion cost.provinces. If LPPI can be applied in these provinces,Potential energy conservation under LPPI in the .more than 9 billion kWh energy and 9 Mt CO,e could11 surveyed provinces in China was shown in Table 2. be saved annually.The first 6 columns were derived based on the dataAt present, groundwater irrigation energy consump-collected by Wang et al. (2012). Based on these tion in Henan, Hebei, Shandong, and Xinjiang (thedata, we calculated energy use for groundwaterlargest food production areas in China) are 2.79x109,irrigation, coefficient k which is the ratio of the area 7.17x109, 6.82中国煤化工yr', respec-without LPPI application to the total irrigated area,tively (TablesMHCNM HG⑥2013, CAAS. Alights reseved. Published by EsevierLtd.1366ZHANG Qing-tao et al.喜三5.售”艺g|g533gg2.3.232.29gsg导冒.g旨1复喜盲&∞占占吕。古只兰尔吕2品|昌二|e吕点曼創急素≌曼°≌虽乓崇°∞≌°曹∞≌°ε°°号S111858年员昌营58号53昌g8;g“g|信|1号886889982|管818|88965818888888888882“g|88998988881中国煤化工YHCNMHG191豆|⑥2013, CAAS. Alights reseved. Published by EsevierLtd.Technologies for Efficient Use of Irigation Water and Energy in China1367Increase net output energy and yield of rice underimproved irrigation technology could bring about hugeintermittent irigationwater and energy savings and should be carefully in-vestigated and implemented.Table 4 shows the potential increase of yield and netoutput energy of rice under ITI in China. Hunan Prov-METHODS AND ANALYSISince provided the largest area for paddy field in China,followed by Jiangxi Province. Ningxia gave the high-Calculation of water and energy savings underest rice yield per unit area in China due to high solarimproved rrigation management measuresradiation and irrigation. The total increment of net out-put energy by ITI in the whole country could reach 2.5x1016 calories. Yield increase by ITI is from 241 toAgricultural energy consumption can be reduced by de-creasing water pumped for irrigation. The United States464.7 kg ha-1 in all provinces. The total yield increaseDepartment of Agriculture Natural Resources Conserva-by ITI would be 107 ton in China (Table 4).tion Service (NRCS) has developed the Energy Consump-tion Awareness Tool, an energy estimation model basedon irrigation methods for major crops. The model evalu-CONCLUSIONates options based on user inputs and estimates the mag-nitude of energy savings that could be achieved underdifferent management systems. The NRCS energy estima-Improved irrigation technologies can exert great influ-tor can also use national averages to estimate energy con-ence upon water and energy use efficiency. The totalservation for individual farms.energy saved by applying improved management mea-The use of a flow meter, irrigation scheduling, and/orsures (the use of a flow meter, irrigation scheduling,regular maintenance and upgrades typically can reduceand/or regular maintenance and upgrades) could reachthe amount of water pumped and the energy for pumping20%, as compared with traditional irrigation methods.over the course of a growing season. Energy saving underthese improved management measures on state-ownedLPPI would save 6.48x109 kWh yr-1 if applied to thefarms in China was calculated using the model.11 Chinese provinces where field surveys wereconducted. Among these, the energy saving potentialEstimation for water and energy savings underfor Hebei and Shandong provinces alone could reachLPPI .1.45x109 kWh yr!. Using LPPI, potential energy con-servation and CO, emissions reduction in 20 otherAt present, approximately 95% of the irrigated lands inChinese provinces where no field survey was con-ducted were estimated at about 2.97x109 kWh per year methods often result in application inefficiency and un-and 2.69 metric tons per year, respectively. The en-even distribution. High runoff and deep percolationergy saving potential for Heilongjiang could reachlosses are cited as the most frequently occurringproblems. About 45% of water is wasted in the course1.77x109 kWh yr', which is the largest in allof water delivery, distribution, leaching， andprovinces. If LPPI is applied in the entire country, .evaporation. Therefore, minimizing deep percolation andaverage annual energy conservation of more than 9runoff while meeting irrigation requirements can increasebillion kWh and average annual reduction of CO, emis-irrigation performance and decrease irrigation energysion of more than 9.0 metric tons could be realized.consumption.Compared with water conveyance using a traditionalCompared with con-tinuous flooding irrigationearth canal, LPPI can decrease irigation energy consump-conditions, intermittent irrigation (ITI) can save wa-tion by 30% due to high water delivery efficiency, whichter and improve yield and water-use efficiency in paddy leads to less pumping (Yan and Bai 1988; Liu 2011). Energyfields. The total increments of net output energy andsaving for LPPI was estimated to be 307.5 kWh hal yrl(Yanyield by ITI in paddy fields across China could reachand Bai 1988). In our study, these data were used to esti-2.5x1016 calories and 107 tons, respectively. Sincemate the energy saving potential by LPPI in differentprovinces.only a small part of irigated agricultural land in ChinaExtensive suI中国煤化工ural China byhas adopted water and energy saving technologies,the Centre for (CCAP) of the .YHCNMHG⑥2013, CAAS. Alights reseved. Published by EsevierLtd.Table 4 Potential increase of yield and net output energy of rice under intermittent irigation in ChinaNet output energy2)Yield per ha Yield increase per ha by ITITotal yieldTotal yield increase by ITIAreaSowing area (x103 ha))Continuous floodingIntermittent irigation (ITI)Increment by ITIirigration (x1013 calorie)(x1013 calorie)(kg))(kg)2) .(x 104 ton)(x104 ton)2)Bejing0.70.8.1250356.300.03Tianjin11.62.9.2102461.811.10.6383.571.08.4.45 60322.9472.702.22.4).231241.210.06Inner Mongolia80.968.875.9737384.054.53.11Liaoning462.7510.748.07 378420.522.89gJilin510.2563.152.97 292415.624.94Heilongjiang1587.81 349.91 490.0140.7117405.71 13064.41Shanghai111.895.1104.905456.389.5 .5.10Jiangsu2112.91796.41 982.7186.4791451.41673.295.37Zhejiang1028.1874.1964.890.76681380.8686.939.15Anhui2129.71810.71 998.5187.86067345.81292.13.65Fujian985.1837.5924.486.95 539315.7545.61.10Jiangxi3029.72575.92843.1267.25213297.11579.4Shandong124.4105.8116.711.0728415.190.65.16Henan508.5432.3477.244.870401.5358.220.42Hubei1 989.61 691.61 867.0175.57 548430.21 501.785.60Hunan3716.83160.03487.8327.86149350.52285.5130.2Guangdong2 1391818.62 007.2188.75251299.31123.164.Guangxi23562003.12210.9207.84768271.8 .1123.4 .64.03Hainan334. 7284.6314. 129398250.7147.2839Chongqing749.3.637.1703. 1616 80387 .6509.529.04206381754.61 03671 827364419.78669Guizhou6092672 46657379.4，10609.2O2 4ζ 987335.627.Yunan1086.21019395.85 88639.436.450.91.05 45310.9Shaanxi124.0136.812.959340.1874.964.2).4)59453.73.0.2254.80.4.75283335.328 378.724 127.626 630.62 503.0631359.717 908.91 020.81王he data in www .china.com.cn. n based on Ni et al. 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