不同地表条件下土壤侵蚀的坡度效应

通过野外人工模拟降雨的方法，对不同地表条件下的径流和产沙的变化与坡度、降雨量、降雨强度等因素进行了相关分析，并在此基础上，就上述过程中的坡度效应进行了评价。结果表明，在相同降雨作用下，坡度对土壤侵蚀影响表现为：光滑地表大于中等粗糙地表大于粗糙地表；但在不同地表条件下，坡度与侵蚀和径流的相关性表现出不同。相对光滑地表，中等粗糙与粗糙的地表。在不同降雨作用下，径流量与侵蚀量，随坡度的变化，表现出不同的变化规律。且存在着一定的临界坡度。这一研究，为该区域坡耕地水土保持措施的配置提供了一定的理论依据，同时也可服务于黄土高原退耕还林（草）工程的实施。

Slope Gradients Effect on Soil Erosion under Different Soil Surface Conditions

In this paper, through artificial rainfall experiments, the relationships between the variation of runoff, sediment and warious influence factors, such as slope gradient, rainfall and rainfall intensity, were analyzed under different soil surface conditions. On the hasis of above work, slope effects on soil erosion were evaluated, too. The results showed that under the condition of same rain fall, the sequence of slope effect on soil erosion, from large to small, was smoothness surface, medium- roughness surface, and roughness surface. However, under different soil surface conditions, the relevancies between slope, runoff and erosion were different. Relative to smooth soil surface, for medium-roughness and roughness soil surface, runoff and erosion showed different variation rules with the variation of slope gradients under different rainfall intensities. Furthermore, there were critical slope gradients existed. The research result not only provided theory basis for the configuration of water conservation measures, but also can server for the conversion of cropland to forest or glass land in Loess Plateau.