Abstract: This research attempted to study systematically and practically the issues of regional ecological adaptability of water in some major crops in upper reaches of Hanjiang river by applying field water balance model, and using GIS technical and risk index of water deficit. The quantitative demand of water and the balance of field water was calculated for 25 counties in Hanjiang river basin. The index of water deficit risk was adopted to analyze spatialtemporal distribution. In general, the precipitation cannot meet the water demand of major crops, and water deficit is the main character of field water balance in Hanjiang river basin. The water deficit for rice is 187.51 mm and the risk index of water deficit reached to 23.26%; thus, the ecological adaptability of water for rice was not well. Orders of ecological adaptability of all the crops were hemp > potato > bean > summer maize > suga > cotton > winter wheat > coil > rice, with hemp and potato showing a well degree of adaptability. It is found that the adaptability for crops at different growing periods may vary significantly for different crops, and in initial growing stage, water deficit for most crops in this area is very obvious, and spring drought can be a severe problem for the crops in this area.

Key words: Hanjiang River Basin, crop water, ecological adaptability, county level