草被地上和地下部分拦蓄径流和减少泥沙的效益分析

研究草被地上和地下部分拦蓄径流和减少泥沙效益对科学评价草被防止土壤侵蚀的作用有重要科学意义。采用模拟降雨试验，分析了草被地上和地下部分拦蓄径流和减少泥沙的效益。结果表明，草被与森林植被一样，能有效防止土壤侵蚀。当草地地面覆盖达90％时，草被拦蓄径流效益达90％以上，而基本上无侵蚀发生。草被地上部分（茎枝＋枯落物）拦蓄径流效益为23．7％，其中茎枝部分拦蓄径流效益为9．0％和枯落物层拦蓄径流效益为14．7％，减少泥沙效益为44．6％；草被地下部分土壤体拦蓄径流效益为72．7％，拦蓄泥沙效益为55．4％。

The Benefit Analysis for Different Layers of Grass Vegetation Reducing Surface Runoff and Sediment Yield

Research on benefits for reducing surface runoff and sediment by different layers of grass vegetation is important to assess the role for grass vegettaion controlling soil erosion. The simulated rainfall experiment is used to quantify benefits for reducing surface runoff and sediment by different layers of grass vegetation. The research results show that grass vegetation, like forest and bush ,can effectively control soil erosion. When surface cover of natural grassland reaches 90% ,the benefits for grass reducing surface runoff is above 90% and not any erosion occurs, The layers of canopy and litter grassland reduce runoff and sediment yield by 23.7% and by 44.6%,separately. The ground layer of soil body with dense root system reduces runoff and sediment yield by 72.5% and 55.4% ,separately.