黄土高原水土保持与水环境

Soil water Conservation and Hydro environment on Loess Plateau

通过分析黄土高原水环境背景特征，认为黄土高原雨水环境差；人工林草地土壤水分长期处在亏缺状态，高产农田、林草、坡地生产力受水分环境制约严重；径流水可利用程度低。生态环境的改善必须借助于水土保持的生物、工程等措施， 首先改善水环境。水土保持措施对在水环境的影响表现为：在地块尺度上，可以汇集雨水、增加入渗、满足作物、植物生长的水分需求平衡。但高耗水的林草地、水分亏缺严重， 在植被建造中还应因地制宜。水土保持措施在流域尺度上表现为增加流域贮水、蒸发， 但使流域径流有所减小。

Through analysing the characteristics of hydro environment on the loess plateau, It is pointed that the precipitation of loess plateau has two characters: one is low, the other is intensive, which can result in a strong soil and water loss. Soil moisture is always in stress statue there. The productivity of basic farmland and forest pasture land has been seriously stressed by water shortage, and the runoff is affected by precipitation. The eco environment should be improved by biological, engineering and chemical measures for soil and water conservation (SWC) in order to adjust water condition on the loess plateau. The SWC measures can bring impacts on hydro environment in two aspects. (1) In land section scale, it can harvest rainwater and increase soil infiltration rate, which made soil can provide more water to plant; (2) For some high water consumption land, such as forest and pasture, the water stress can only be modified, and the hydro environment should be considered into the constructing of vegetation; (3) For watershed scale, the SWC can increase water storage and evaporation, meanwhile, it can decrease runoff.