Irrigation-Induced Changes in Evapotranspiration Demand of Awati Irrigation District, Northwest China: Weakening the Effects of Water Saving?

摘要

The evapotranspiration demand of the Awati irrigation district has changed with irrigation development since 1980. During the first period of traditional irrigation expansion from 1980 to 1997, reference crop evapotranspiration ( ET 0 ) decreased as irrigation intensity increased. Since the second period of water-saving irrigation extension began in 1998, the gross irrigation quota has decreased as the water use efficiency improved, whereas ET 0 has been increasing accordingly. The increasing evapotranspiration demand has enlarged the irrigation water requirement per unit area, which partly weakens the effects of water-saving irrigation. Findings show that irrigation-induced changes in evapotranspiration demand should be considered when evaluating the performance of water-saving technologies in irrigation districts in arid areas.