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植被是防止地面水土流失的积极因素,但在三峡库区紫色土关于植被对水土流失的影响还相对比较薄弱。本研究通过人工模拟降雨试验,分析不同草地覆盖度对紫色土坡地径流产沙的影响,定量研究不同草地覆盖度的减水减沙效益。结果表明:流量随草地植被覆盖度的增加而减小,小雨强时表现特别显著。特别是当植被覆盖度>60%后,径流量明显低于裸地及20%,40%植被覆盖度;植被覆盖度越高,植被降低径流含沙率的作用也就越明显,径流含沙量就越低;与草地的减沙功能相比,其削减径流作用明显弱于减沙效应,且盖度对坡面的减水特征值影响不太明显;植被覆盖的减流减沙效益在中小雨强时随雨强的增加而增加,在大雨强时,其减流减沙效益反而降低。
Vegetation is a positive factor to prevent water and soil erosion on the ground, but the influence of purple soil on soil erosion in the Three Gorges Reservoir Area is relatively weak. In this study, artificial rainfall simulation experiments were conducted to analyze the effects of different grassland coverage on runoff and sediment yield of purple soil slopes. The benefits of water and sediment reduction with different grassland coverage were quantitatively studied. The results showed that the flow rate decreased with the increase of grassland vegetation coverage, especially when the rainfall intensity was low. Especially when the coverage of vegetation is> 60%, the runoff is obviously lower than bare land and 20% and 40% of vegetation coverage. The higher the vegetation coverage is, the more obvious the role of vegetation in reducing runoff and sediment yield is. The lower the amount of sediment; grassland than the function of sand, its role in reducing runoff was significantly weaker than the sand effect, and the cover on the slope of the water feature values less obvious; When the rainfall intensity is small, the rain intensity increases with the increase of rainfall intensity, but the benefit of reducing flow and sediment decreases.