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.
