Zhang Qing-tao;Xia Qing;Liu, Clark C. K.;Shu Geng

Univ Calif Davis, Dept Plant Sci, Davis, CA 95616 USA;Peking Univ, Shenzhen Grad Sch, Sch Environm & Energy, Key Lab Urban Habitat Environm Sci & Technol, Shenzhen 518055, Peoples R China;Univ Hawaii Manoa, Dept Civil & Environm Engn, Honolulu, HI 96822 USA

water and energy efficiency;irrigation management;low pressure pipeline irrigation;energy saving potential;intermittent irrigation

While the shortage of water and energy is a well-recognized worldwide natural resources issue, little attention has been given to irrigation energy efficiency. In this paper, we examine the potential energy savings that can be achieved by implementing improved irrigation technologies in China. The use of improved irrigation management measures such as a flow meter, irrigation scheduling, and/or regular maintenance and upgrades, typically reduces the amount of water pumped over the course of a growing season. The total energy saved by applying these improved measures could reach 20%, as compared with traditional irrigation methods. Two methods of irrigation water conveyance by traditional earth canal and low pressure pipeline irrigation (LPPI) were also evaluated. Our study indicated that LPPI could save 6.48 x 10(9) kWh yr(-1) when applied to 11 Chinese provinces. Also, the CO2 emission was reduced by 6.72 metric tons per year. Among these 11 surveyed provinces, the energy saving potential for two provinces, Hebei and Shandong, could reach 1.45 x 10(9) kWh yr(-1). Using LPPI, potential energy saved and CO2 emissions reduced in the other 20 Chinese provinces were estimated at about 2.97 x 10(9) kWh yr(-1) and 2.69 metric tons per year, respectively. The energy saving potential for Heilongjiang, a major agriculture province, could reach 1.77 x 10(9) kWh yr(-1), which is the largest in all provinces. If LPPI is applied to the entire country, average annual energy saving of more than 9 billion kWh and average annual CO2 emission reduction of more than 9.0 metric tons could be realized. Rice is one of the largest users of the world's fresh water resources. Compared with continuous flooding irrigation, intermittent irrigation (ITI) can improve yield and water-use efficiency in paddy fields. The total increments of net output energy and yield by ITI in paddy fields across China could reach 2.5 x 10(16) calories and 10(7) tons, respectively. So far only a small part of agricultural land in China has adopted water and energy saving technologies. Therefore, potential water and energy savings in China by adapting improved irrigation technology could be significant and should be carefully studied and applied.