模拟降雨下坡面草带分布对产流产沙过程的影响

为深入探讨坡面植被分布对产流产沙过程的影响,定量分析植被分布与坡面产流产沙的关系,通过人工降雨试验,在15°坡面条件下,对不同植被覆盖度（40%,60%）、不同降雨强度（30,60,90 mm/h）和不同植被分布位置（相对距离为0,0.2,0.4,0.6,0.8,1.0）条件下的坡面产流产沙进行观测,分析不同植被分布条件下的水土保持作用,提出了不同覆盖度下控制水土流失的植被优化配置。结果表明：（1）在一定坡度和降雨强度条件下,不同植被分布条件下坡面产流率和产沙率均表现为先迅速增加后趋于稳定的变化趋势;（2）坡面平均产流率和产沙率随着相对距离的增加表现出先减小后增大的趋势,植被相对距离为0.2的坡面的平均产流率在不同实验条件下均为最小;（3）通过随机森林算法发现,降雨强度和植被覆盖度对产流具有重要影响,降雨强度和植被相对距离对产沙具有重要影响;（4）当植被覆盖度为40%时,以减少径流和泥沙为主要目标的最优化植被相对位置分别为0~0.36,0~0.31;当植被覆盖度为60%时,以减少径流和泥沙为主要目标的最优化植被相对位置分别为0~0.43,0~0.22。表明坡面植被分布对产流产沙有重要的影响,在相同植被覆盖度条件下,草带的相对距离越小,对减少径流和泥沙的作用较好。研究成果可为生态恢复过程中植被的优化配置提供理论依据和数据支撑。

Effect of Grass Belt Distribution on Runoff and Sediment Yield Under Simulated Rainfall

In order to deeply explore the influence of slope vegetation distribution on the process of sediment and runoff yield, and quantitatively analyze the relationship between vegetation distribution and sediment and runoff yield on slope, through artificial rainfall test, under the condition of 15° slope, the sediment and runoff yield process were observed under the conditions of different vegetation coverages (40% and 60%), different rainfall intensities (30, 60 and 90 mm/h) and different vegetation distribution positions (relative distance 0, 0.2, 0.4, 0.6, 0.8 and 1.0). The effects of soil and water conservation under different vegetation distribution conditions was analyzed, and the optimal vegetation allocation for controlling soil and water loss under different vegetation coverages was proposed. The results showed that:(1) Under a certain slope and rainfall intensity, the runoff and sediment yield increased rapidly at first and then tended to be stable under different vegetation distribution conditions. (2) In this study, the average runoff and sediment yield firstly decreased and then increased with the increasing of the relative distance. The average runoff yield of the slope with the relative distance of 0.2 was the minimum under different experimental conditions. (3) The random forest algorithm showed that rainfall intensity and vegetation coverage had important impact on runoff yield, and rainfall intensity and vegetation relative distance had important impact on sediment yield. (4) When the vegetation coverage was 40%, the optimal vegetation relative positions were 0 to 0.36 and 0 to 0.31, respectively, with the main objective of reducing runoff and sediment. When the vegetation coverage was 60%, the optimal relative vegetation positions were 0 to 0.43 and 0 to 0.22, respectively, with the main goal of reducing runoff and sediment. This study showed that slope vegetation distribution had an important impact on sediment yield and runoff. Under the same vegetation coverage, the smaller the relative distance of the grass belt was, the better the effect of reducing runoff and sediment. The research results could provide theoretical basis and data support for optimal allocation of vegetation in the process of ecological restoration.