Effects Of Simulated Rainfall On Slope Erosion Under Different Vegetation Patterns

In this study, field simulation study was adopted to analyze runoff and sediment productionon slope land under different vegetation pattern and there influence factors. At the same time, thereliability, superiority and inferiority between VFC and LAI quantitative characterisation of soilerosion was studied. The main results are as follows:(1)Genrally, the declining sediment concentration fluctuation range order was bared slope,pure shrub land, pure grass land, and shrub and grass land. Sediment concentration increasedrapidly in the beginning stage of rainfall, then reduced and keeped stable. Sediment concentrationwere positively correlated with slope, rainfall intensity and negative correlated with vegetationcover. When vegetation coverage changed from80%to60%, sediment concentration got amaximum increase. The sediment concentration increased in the later rainfall stage under higherrainfall intensity, slope and lower vegetation coverage.(2)The declining time required whicn from rainfall started to the sediment concentration gotstable order was bared slope, pure shrub land, pure grass land, and shrub and grass land. Thesediment concentration had the smaller difference and the time required got shorter under thehigher vegetation coverage.(3)Runoff and sediment yield were positively correlated with rainfall intensity, slope, andnegative correlated with vegetation cover. When vegetation coverage changed from60%to80%,runoff and sediment yield got a maximum increase. The weakening effects of runoff andsediment yield increased lightly if the vegetation cover was over80%. The weakening effects ofrunoff and sediment yield had the smaller difference between high and low vegetation cover.(4)The declining soil conservation benefit order was bared slope, pure shrub land, pure grassland, and shrub and grass land. The benefit was positively correlated with vegetation cover andslope. When the slope was same,the benefit positively correlated with rainfall intensity if thevegetation coverage was high and negative correlated with rainfall intensity if the vegetationcoverage was low.(5)Using LAI as a vegetation indicator to reflect the process of soil erosion was reliable. Theimpact of runoff and sediment yield on VFC and LAI showed significant index decreased. Theslope, rainfall intensity, VFC, LAI was both the main factors affecting runoff and sediment. Usethe above factors as independent variables, cumulative runoff and cumulative sedimentconcentration as dependent variables, building regression equations, these regression equationsreach0.01level of significance.