香根草植物篱带宽对紫色土坡地产流产沙的影响

为研究植物篱篱带宽度对紫色土坡地产流产沙过程的影响,寻求有效控制水土流失的最优植物篱带宽度,采用人工模拟降雨试验对3种篱带宽度(20,30,40cm)、不同雨强(30,60,90mm/h)下的紫色土坡地产流产沙过程进行研究。结果表明:(1)植物篱能有效延缓紫色土坡面产流时间,坡面产流量与篱带宽度能拟合为二次方程(R2=0.99)。随篱带宽度的增大,流速减小,且篱带内部的流速下降最明显,流速变化曲线波动幅度变小。(2)植物篱在产沙过程前期有效抑制坡面产沙量的增长,坡面产沙量随篱带宽度的增大而减少,且当雨强为30,90mm/h时,二者拟合的二次方程R2达到0.99。(3)篱带宽度对产流、产沙量的影响均为极显著。30mm/h雨强下、宽度为30cm的篱带可达到显著的减流减沙效益,是能有效控制水土流失的最优植物篱带宽度。

Effects of Vetiveria zizanioides L. Hedgerow Width on Runoff and Sediment Yield on Purple Soil Slope

In order to study the effects of hedgerow width on runoff and sediment yield process of purple soil slope and explore the critical hedgerow width for effective control of soil erosion, three hedgerow with different width (20, 30, 40 cm) were set up to analyze the runoff and sediment yield of purple soil slope land under different rainfall intensities (30, 60, 90 mm/h). The results showed that:(1) Hedgerow could effectively delay runoff generation time on purple soil slope, and the relationship between the runoff yield and the hedgerow width could be fitted into a quadratic equation (R²=0.99). With the increase of hedgerow width, the flow rate decreased, and the flow rate inside the hedgerow decreased most obviously, and the fluctuation range of the flow rate curve decreased. (2) Hedgerow could effectively restrain the increase of sediment yield on the slope in the early stage of sediment yield process, and the sediment yield on the slope decreased with the increase of hedgerow width. When the rainfall intensity was 30 mm/h and 90 mm/h, the R² of quadratic equation between the sediment yield and the hedgerow width was 0.99. (3) The hedgerow width caused an extremely significant effect on runoff and sediment yield. Under 30 mm/h rainfall intensity, the hedgerow with a width of 30 cm could achieve a remarkable benefit of reducing runoff and sediment yield.