Abstract: In this paper, the spatial-temporal distribution and evolution trend of precipitation in the water-use area of Shiyang River Basin in Hexi Corridor was studied, and the water balance in different reaches of the Basin was calculated by using potential transpiration, arid index, and difference of transpiration and precipitation. The results showed that during the period of 1980s-1990s, the total precipitation in the Basin had a gradual but slight increase. The recipitation increased in spring and summer but decreased in autumn and winter, while the annual mean potential transpiration was 1 026.1 mm, with a gradual increase from upper to lower reaches. In 1970s-1990s, the potential transpiration had an increasing trend, with an annual average of 4.1-43.6 mm, but decreased in the order of summer> spring>autumn >winter, with an average ranging from 403.5 to 521.6 mm. The average arid index was 0.002, with a maximum of 0.581 in the lower Minqin region. During the past 30 years, the climatic arid index of this Basin increased, indicating a dryer and dryer climate, and the average annual lack of water was 810.7 mm, suggesting a severe deficit of water resources. A reasonable water resources deployment proposal was suggested to response this climatic change and to promote a sustainable regional economic development.

Key words: Water deficit, Maize, Hydraulic conductivity, Anatomic structure