中文摘要：

利用SWAP（Soil-Water-Atmosphere．Plant）模型对黄土高原水蚀风蚀交错区坡地土壤一植被一大气系统中的水循环进行数值模拟。结果显示，SWAP模型很好的模拟了不同土地利用方式条件下的土壤水循环过程。根据模拟结果，水蚀风蚀交错区的丰水年份，农地和种植第一年的紫花苜蓿地季末土壤水分稍有盈余，谷子和紫花苜蓿的日蒸散量分别为1．2．2．6mm和1．2—2．5mm。

英文摘要：

The soil-water balance is very important in the ecosystem restoration in the typical water-wind erosion crisscross region on the Loess Plateau. An effective way to study the water balance is modeling. In this paper, a numerical model, soil-wa- ter-atmosphere-plant model （SWAP）, is used to simulate the water balances and evapotranspiration in different land use patterns based on field observations. The results of SWAP model simulating soil-water balance are consistent with the observed values in different land use patterns. The model can simulate soil-water dynamics of the loess slope land after some parameters are adjusted according to the measured values. The outputs of SWAP model can be used to analysis water balance daily, and the daily evapotranspirations of millet and alfalfa are 1.2 - 2.6 and 1.2 - 2.5, respectively.