不同降雨强度下地面坡度对红壤坡面土壤侵蚀过程的影响

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

通过室内模拟降雨试验,研究了不同降雨条件下地面坡度对红壤坡面产流过程和侵蚀过程的影响,结果表明,红壤坡面起始产流时间随坡度的增加有所提前,但不明显,坡面起始产流时间的早晚主要受降雨强度控制;坡面径流量随雨强的增大而增大,随坡度的变化比较复杂,在雨强为50mm/h时,径流量随坡度的增加而减小,在雨强为75mm/h时,径流量随坡度的增加先增大后减小;不同降雨强度下各坡度的侵蚀产沙率都是在降雨初期急剧上升,随后以指数下降,形成一个向左倾斜的曲线。坡度对坡面侵蚀产沙的影响随雨强的增大而增强;红壤坡面土壤侵蚀量随雨强的增大明显增大,随坡度的增加,在50mm/h小雨强时呈现先增加后减小的变化趋势,在坡度20°附近存在临界坡度;在75mm/h雨强下,侵蚀量随坡度增大而增大。

The simulated rainfall experiment was used to quantify the effects of slope gradients on runoff and soil erosion processes on red earth hillslopes under different rainfall intensity conditions.The results showed that the initial slope red soil runoff rates increased the time in advance with the slope,but weren＇t obvious,start time of slope runoff was mainly affected by rainfall intensity control sooner or later;slope runoff increased with rainfall intensity increases,with slope gradient was more complex,in the rain intensity of 50 mm/h,the runoff with slope decreased with increased in rainfall intensity for the 75 mm/h,the increase in runoff with slope then decreased;Under different rainfall erosion of the slope of the rainfall rates were in the initial sharp rise,followed by the index fell to form a lean to the left of the curve.Slope of the impact of slope erosion increased with rainfall intensity increased;The amount of red soil erosion increased with rainfall intensity increased significantly,with the slope of the increase in the 50 mm/h rain intensity at first increased and then decreased when the trend,there was a critical near the 20° slope;at 75 mm/h rain intensity,erosion increased with slope.