采用电子蒸散计(Lysimeter)逐日测定春小麦和玉米生育期的蒸散(地面蒸发和植物蒸腾)量,结果表明,作物的蒸散量随生育期的进程而变化,并受供水条件所制约。春小麦全生育期的最大蒸发蒸腾虽约312mm,最小蒸发蒸腾量245mm;玉米全生育期的蒸发蒸腾量约468mm。春小麦套种玉米的增产节水效果显著,其产量比单种春小麦和玉米的产量高约50％,而蒸散耗水量比单种的低18％。本文就河西干旱区农业节约用水合理灌溉问题作了讨论。 Evapotranspiration (Lysimeter) was used to measure evapotranspiration (evapotranspiration and plant transpiration) in spring wheat and maize respectively. The results showed that the evapotranspiration of crop varied with the growth period and was controlled by the water supply conditions. Although the maximum evapotranspiration of spring wheat is about 312mm during the whole growth period, the minimum evapotranspiration is 245mm. The transpiration amount of corn during the whole growth period is about 468mm. Spring wheat intercropping corn has significant increase yield and water saving effect, and its yield is about 50% higher than that of single spring wheat and maize, while evapotranspiration water consumption is 18% lower than that of single type. This article discusses the reasonable agriculture irrigation water saving problem in Hexi arid area.