中文摘要：

土壤水分是农作物生长的主控因子,对土壤侵蚀过程有着重要的影响.在水蚀风蚀交错带的强烈侵蚀中心——陕北神木县六道沟小流域内,选择5种典型的土地利用类型,修建5 m×21 m标准径流小区,从2004年5月到10月,在天然降雨试验条件下,对其水分变化特征进行了观测.研究结果表明,在观测期内,不同土地利用方式的土壤储水量动态变化趋势与降雨量的变化趋势基本一致,土壤储水量的最高值和最低值分别出现在6月上旬和7月上旬;各小区土壤水分循环过程基本均为“消耗—补偿—消耗”,水分变幅随土层深度增加而变小;5个小区的蒸散耗水量大小依次为柠条地〉荒草地〉退耕地〉黑豆地〉谷子地,径流量大小依次为黑豆地〉谷子地〉退耕地〉荒草地〉柠条地.柠条蒸散耗水量最大,地表径流量最少,说明柠条灌丛具有良好的水土保持效益和较高的水分利用率.在侵蚀严重的水蚀风蚀交错带地区,合理规划发展柠条林等深根性植物是防止土壤侵蚀、利用深层土壤水分的有效方法.

英文摘要：

Five representative land use types were selected to monitor the soil moisture in Liudaogou Catchment,Shenmu County,northern Shaanxi Province of northwestern China,in the center of the water-wind erosion interlaced region from May to October,2004.The five land use patterns were Caragana korshinskii land,Glycine soia land,Setaria italica land,natural grassland and de-farming grassland.The data were obtained under the condition of natural rainfall,and the results showed that the dynamic change tendency of water-storage capacity of the five land use types was accordant with that of natural rainfall,and the maximum and the minimum capacity happened respectively in the first ten days of June as well as July;the moisture circulation processes of the five land use patterns were nearly all ＂consumption-compensation-consumption＂,and the variation scope of soil moisture decreased with the increase of soil layer depth;the sort order of the transpiration and evaporation capacity within the observation period was C.korshinskii land〉natural grassland〉de-farming grassland〉G.soia land〉S.italica land,and that of total runoff produced within the observation period was G.soia land〉S.italica land〉de-farming grassland〉natural grassland〉C.korshinskii land.For C.korshinskii land,its transpiration and evaporation capacity was the maximum while its total runoff was the minimum,and this shows that its efficiency of water application is high and it has better effects on the soil and water conservation,and cultivating deep-rooted plants is the potent way to prevent the soil erosion and utilize the deep subsoil water.