地表砾石对降雨径流及土壤侵蚀的影响

Effects of Rock Fragments on Runoff and Soil Erosion

山区土壤表层常有大量砾石覆盖,地表砾石覆盖会对降雨入渗产生影响,从而影响径流和土壤侵蚀。利用人工降雨试验来评价北京山区普通褐土上不同砾石覆盖度对径流和土壤侵蚀的影响。试验降雨强度为30,67,92mm/h,土盘(1m×0.5m)坡度为20°,砾石覆盖度为0,5%,10%,20%,40%和60%。研究结果表明:对试验土壤,径流量随砾石覆盖度增加呈线性减小。水流流速和土壤侵蚀量随砾石覆盖度的增加呈负指数递减。降雨强度对径流量和土壤侵蚀量与砾石覆盖度之间的关系不存在影响。研究结果可为北京山区的土壤侵蚀预报提供数据基础。

Soil commonly contains large numbers of rock fragments in surface layer.Rock fragments on the soil surface have effects on infiltration,thus affect runoff and soil erosion.In this study,simulated rainfall experiments have been conducted on soil tray with 1 m long and 0.5 m wide in the laboratory in order to evaluate the effects of rock fragment cover on runoff and soil erosion.3 rainfall intensities （30,67,92 mm/h） and 6 levels of cover of rock fragments （0,5%,10%,20%,40%,and 60%） were included.The experimental slope was 20°.The results reveal that rock fragment cover enhanced infiltration and reduced runoff.Runoff decreased linearly with rock fragment cover.Flow velocity decreased and resulted in reduced sediment yield.The exponential decay function can be found between flow velocity and sediment yield and rock fragment cover.Rainfall intensity had no effects on the relationships between runoff amount and rock fragment cover,and between soil erosion and rock fragment cover.These results may provide parameters for soil erosion assessment.