植被在坡面的不同位置对降雨产沙量影响

植被在坡面的不同位置,对坡面保持水土的作用是不同的。通过野外人工模拟降雨试验比较了在相同面积条件下,植被分别分布在坡面上部、中部和下部时,坡面降雨产沙量的差异。结果显示,对保土能力来说,坡下植被>坡中植被>坡上植被,而且这种差异在小雨强下更加明显。这充分说明,坡下部的植被在保护坡面土壤不被流失方面起着举足轻重的作用。因此保护好坡下部的植被可以有效地防止坡面水土流失。

Effect of Vegetation's Position on Slope on Sediment Yield Induced by Rainfall

Vegetation at different slope positions has different roles in soil and water conservation.This paper compares the discrepancies of sediment yield induced by rainfall with vegetation distributed in the upper,middle and lower slopes.Results indicate that vegetation distributed in the lower slope conserves soil better than that in the upper and middle slopes.As rainfall intensity decreases,the discrepancies become more distinct.So,vegetation in the lower slope is very important to soil and water conservation on slopping land.The Loess Plateau is the typical area suffering from severe soil and water loss,on which rainstorm occurs rarely.The rainfall intensity which induces soil erosion is rarely greater than 50 mm/h.Under the condition,vegetation in the lower slope can play an important role.Therefore,we should well protect vegetation in the lower slope to conserve soil.We put forward some suggestions for a better landuse on slopping land.