The spatial variation characteristics of water requirements for main crops in Sichuan Province, P. R. China

Through the website of International Water Management Institute, the referenced evapotranspiration (ET0) was found which was calculated by the meteorological data during 1961-1999 from 147 stations in Sichuan Province. Further, according to the crop coefficients of rice, maize, wheat, rape, the water requirements (ET) of main crops were estimated by using Food and Agriculture Organization (FAO) Penman-Monteith equation. The spatial distribution characteristics of ET0 were drawn by Spatial Interpolation method by means of Geographic Information System (GIS). Results showed that: (1) the maximum and minimum of ET0 were at summer and winter respectively, and the maximum of ET0 in three climatic sub-zones occurred at different times; (2) the crop growth stage was different, so ET of different crop was significantly different, and ET of crops at the same region from high to low were: rice> maize> wheat> rape; (3) spatial distribution of crop water requirements changed largely, and the highvalue zone of crop water requirement was mainly distributed in the southwest mountain areas, and the most areas of Aba belonged to low-value zone.