黑麦草对黄土坡面降雨产流产沙过程的影响

为研究草地对土壤侵蚀过程的影响,选用黄绵土人工种植草地,采用室内模拟降雨试验研究黑麦草不同覆盖度（0、25%、50%和75%）对3种降雨强度（60、90和120 mm/h）坡面产流产沙过程的影响。结果表明：黑麦草覆盖可以显著减小侵蚀产沙。在坡面土壤预饱和的条件下,坡面产流、产沙与时间呈线性关系;累计产流量随降雨强度线性增加;同一降雨强度条件下,草地覆盖度对累计产流量影响不显著;草地坡面水流含沙量、输沙率、次降雨产沙量均随覆盖度增大而降低,随降雨强度增大而增加;3种降雨强度条件下,无黑麦草覆盖坡面水流含沙量差异不显著,次降雨产沙量和输沙率随着降雨强度的增加而增大。研究结果可为土壤侵蚀预报模型建立及水土保持措施的制定提供理论参考。

Impacts of rye grasses on runoff and sedimentation processesfrom loess slopes

The vegetative coverage on the slope,as an effective measure for soil and water conservation can regulate runoff and sedimentation.A series of flume experiments on the slopes set at 15°,under 4 rye grass coverages(0,25%,50%,75%),were conducted under 3 rainfall intensities(60,90,120 mm/h) with silty-loamy(loess) soil,to study the impacts of the rye grass coverages on the runoff and sedimentation processes.The results showed that the rye grass significantly reduced sediment yields.Under saturation conditions,the runoff and sediment yield processes were linear functions of time.No significant differences of runoff yiled were found amongst different coverages of rye grass,but they increased with rainfall intensity.The sediment concentration,sediment yield and sediment delivery rate from the grassed slopes decreased with the grass coverage,and increased with the rainfall intensity.At the slopes without grass cover,there exited no significant differences of the sediment concentrations under different rainfall intensities,while sediment yield and sediement delivery rate increased with rainfall intensity.Understanding the impacts of the rye grass coverage on the runoff and sedimentation processes from loess slopes is important to the managements of water conservation.