不同雨强条件下坡度对红壤坡面侵蚀的影响

坡度是红壤坡面侵蚀的重要因子,通过室内模拟降雨试验研究3个降雨强度(1.0,1.5,2.0 mm/min),3个坡度(10°,15°,20°)条件下坡度对红壤坡面产流、产沙过程影响。结果表明:(1)相同雨强下,坡面初始产流时间随坡度增加逐渐缩短,坡度与坡面径流量呈正相关关系;相同坡度下,随雨强增加初始产流时间及坡面径流量差异均减小。(2)坡度对红壤坡面含沙量的影响表现为平均产沙量随坡度增加而增大,其中15°坡度下坡面产沙过程波动较大。(3)坡度对坡面径流量的贡献率在60%以上,而坡度对坡面产沙量贡献率保持在30%左右。通过分析不同降雨条件下坡度对红壤坡面侵蚀过程影响,以期为红壤水土流失地区的水土保持预测与措施布没提供相应理论参考。

Effect of Slope Gradients on Red Soil Erosion under Different Rainfall Intensity

Slope gradient is an important factor affecting the surface slope erosion of red soil.The objectives of this study were to investigate the impact of slope gradients on runoff and sediment yield erosion processes.Three rainfall intensities (1.0,1.5,2.0 mm/min) and three slope angles (10°,15°,20°) were comparatively studied under simulated rainfall.Results showed that:(1) Under the same rainfall intensity,the time of the initial runoff were shortened with the increasing slope gradients on red soil,slope angle and runoff volume were positively correlated;under the same slope gradient,both the time of initial runoff and runoff volume decreased with the increasing rainfall intensity.(2) The effects of slope gradients on the sediment yieldwere more complicated,an increasing slope gradient generally increased the average sediment yield,which had greater volatility under 15°.(3) The contribution of slope gradients to runoff volume was more than 60％,and to sediment yield was above 30％.These findings provided theoretical basis for erosion prediction and prevention in erosion area of red soil.