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通过坡地设置径流场、雨量点进行定位实测方法，分析降雨量与林草地表土流失、森林类型与地表径流及土层孔隙性关系，阐明森林和灌草地均有很好的减少表土侵蚀的功能．多层次的植被覆盖和保持良好的地面枯落物层的森林地，只有４．３％以下的降雨量形成地表径流，比单层乔木结构纯林减少以上．多年实测资料表明，减少林地表土侵蚀功能最好的森林类型为乔、灌、草或乔、草加枯落物层结构，其植被垂直投影盖度接近１，各层累加总盖度＞１．４．灌草结构坡地也有较好的防止表土侵蚀功能．郁闭度过大单层乔木纯林，地表裸露时功能最差．要减少林草地表土流失，坡地在雨季必须有良好地面覆盖．
Through the setting of the runoff field and rainfall points on the slope, the measured and measured methods were used to analyze the relationship between the rainfall and the loss of topsoil, the type of forest and the runoff of the soil and the porosity of the soil. The results showed that both the forest and the shrub-grassland had a good function of reducing topsoil erosion. At multi-level vegetation cover and forest land with good ground litter, only 4.3% or less of rainfall forms surface runoff, which is less than that of single-layer arbor-only forests. The measured data for many years show that the forest types with the best function of reducing topsoil erosion are Qiao, Guan, Cao or Qiao, grass plus litter layer structure. The vertical projection coverage of the vegetation is close to 1, and the cumulative total coverage of each layer is> 1.4 . Shrub grass slope is also better to prevent topsoil erosion function. Canopy density is too large monolayer tree pure forest, the worst feature when the surface bare. To reduce the loss of forest and grass surface soil, slope in the rainy season must have good ground cover.