本文依据田间试验数据 ,采用Jensen模式 ,研究了黄土旱区冬小麦、春玉米这两种优势作物的—水分模型 .研究结果表明 ,小麦在播种～返青期缺水敏感指数 (λ)最大 ,对缺水最为敏感 ;拔节～抽穗期次之 ,然后是抽穗～灌浆期 ,而灌浆～成熟期和返青～拔节期的敏感性最小 .总耗水量在 32 0～ 42 0mm之间 ,灌水量为 2 6 0～ 30 0mm左右、且分布在冬前和拔节～抽穗期是节水高产高效的灌水模式 .玉米拔节 -抽穗期和抽穗 -灌浆期对缺水最敏感 ,拔节前和灌浆 -成熟期敏感性小 .说明拔节后到抽穗期补水对产量作用最大 ,其次为抽穗 -灌浆期 .这为黄土旱区制定灌溉制度提供了重要理论依据 Based on the field data and the Jensen model, this paper studied the water-crop model of two dominant crops, winter wheat and spring maize in the loess dry land.The results showed that the water sensitivity index (λ) of wheat in sowing- Water is the most sensitive; the jointing ~ heading stage is the second, followed by the heading ~ filling stage, while the sensitivity of filling ~ ripening stage and rejuvenation ~ jointing stage is the smallest.The total water consumption is between 32 0 ~ 42 0mm and the irrigation amount is 26 0 ~ 30 0mm, and distributed in winter and jointing ~ heading stage is a water-saving, high yield and efficient irrigation mode.At jointing-heading stage and heading-filling stage, corn is the most sensitive to water deficit, before jointing and filling-maturity The results showed that water supplementing effect after jointing to heading stage had the greatest effect on yield, followed by heading-filling stage, which provided important theoretical basis for formulating irrigation system in the loessial and arid regions