土壤表面特性与坡度对产流产沙的影响

通过不同坡度下，前期有、无发育土壤结皮及前期打破土壤结皮的对比试验．分析了土壤表面特性与坡度对产流产沙的影响。结果发现，土壤结皮与坡度对产流均有影响，土壤结皮与坡度均通过降低入渗而增加产流；随着坡度的增加土壤结皮的贡献率降低，坡度的贡献率增加；不同坡度下，随着降雨历时的增加，土壤结皮的影响在降低。产生土壤结皮后，侵蚀力的增大远远大于抗蚀力的增大，导致产沙量增大。打破土壤结皮下产流量与产沙量仍旧很高，说明仅在表层扰动并不能彻底消除土壤结皮的影响。

Effects of Soil Surface Characteristics and Gradient on Runoff and Sediment Yield

Effects of soil surface characteristics and gradient on runoff and sediment production were analyzed by comparable experiments. It showed that soil crust and gradient both have effects on runoff by reducing infiltration; the contribution of soil crust is decreasing with gradient, whereas the contribution of gradient is increasing with gradient. On each gradient, the effects of soil crust are decreasing with rainfall time. Once soil crust formed, the increment of erosive force is larger than that of anti-erosive force, and so induces the improvement of sediment yield. It is still high of runoff and sediment yield for broken crust soil, and so it is impossible to eliminate the effects of soil crust completely only disturbing the soil surface.