Abstract:

Water resources in Yangtze River Basin is richer, but water of per capita is only 30 percent of the world average. How can we improve agricultural water use efficiency and overall agricultural production capacity in Yangtze River Basin? It is not only an urgent issue in the current water conservancy work, but of great significance to agricultural sustainable development and food security. Because green water resource of annual precipitation is of great importance to crop growth, the green water is included in total agricultural water consumption different from the one from current statistics. Ten provinces are taken into consideration except Tibet autonomous region (TAR) and Zhejiang province because TAR is taking as not agriculture but the livestock industry and most area of Zhejiang lies in Southeastern rivers. Thus the research objects include Shanghai, Jiangsu, Anhui, Jiangxi, Hubei, Hunan, Yunnan, Qinghai, Chongqing and Sichuan. Then some indicators, for example amounts of fertilizer, sown area of agricultural crops, agricultural machines, agriculture labor and agriculture water consumption, are selected so as to estimate agricultural water use efficiency of Yangtze River Basin. Based on the panel data of 10 provinces in Yangtze River Basin from 1998-2011, agricultural water use efficiency is estimated by the method of superefficiency DEA. On the basis of the efficiency estimation, the factors of agricultural use water efficiency are tested by Tobit model. Based on the water efficiency measurement method of Hu &Wang(2006), DEA model is used to measure agricultural water use efficiency from basin level. Moreover, according to features of water resources and agricultural water use, etc., dummy variables S1， S2， S3 are introduced in Tobit model. In order to know the deeper causes of the change of the agricultural water efficiency, some factors are observed including the water resource of per capita, annual precipitation, crop planting structure, watersaving irrigation technology, irrigation fees and opening up of agriculture. Some conclusions are as follows: ①During the research period, agricultural water use efficiency shows rise trend in waves; the efficiency of upper，middle and low reaches in Yangtze River Basin is on the decrease. ②Irrigation fees, watersaving irrigation technology and opening up of agriculture have significant positive effects on the efficiency. And annual precipitation has significant negative effects on the efficiency. In addition, water resource of per capita has negative effects on the efficiency, but not statistically significant. Results show that improving agricultural use efficiency in Yangtze River Basin, especially the middle and upper reaches, in which water resources is richer; in aspect of agricultural watersaving policies, adjusting agricultural irrigation water price, strengthening agriculture technology innovation and expanding opening up of agriculture can get remarkable watersaving effects.