晋西黄土区坡耕地不同下垫面水土流失对侵蚀性降雨的响应

Response of Soil and Water Loss on Different Underlying Surfaces of Sloping Farmland to Erosive Rainfall in the Loess Area of Western Shanxi Province

为了揭示晋西黄土区不同类型坡耕地的产流、产沙及入渗规律,以4种下垫面(玉米、马铃薯、弃耕地、裸地)径流小区为研究对象,采用水量平衡的方法,分析了降雨因子对地表径流深、泥沙流失量和入渗率的影响。不同下垫面径流小区的径流深、泥沙流失量从小到大依次表现为玉米地<马铃薯地<弃耕地<裸地,入渗率则反之。与玉米地相比,马铃薯地、弃耕地和裸地的径流深增加了58.95%,146.85%,261.48%;泥沙流失量增加了50.45%,94.98%,240.06%;入渗率下降了5.68%,14.25%,25.36%。玉米地、马铃薯地、裸地径流深与I10,I30,P×I10,P×I30呈较好的幂函数关系,弃耕地径流深与之呈较好的一次函数关系,泥沙流失量也表现出相似趋势。入渗率随雨强增大呈减小趋势。与马铃薯地、弃耕地和裸地相比,玉米地在不同程度上有减流减沙、增加入渗的特性。

In order to investigate characteristics of runoff,sediment and infiltration of sloping farmlands under different land uses in the loess area of western Shanxi,four underlying surfaces(maize,potato,abandoned farmland,bare land)were used as research objects in runoff plot experiment.Water balance methods were used to analyze the relationship between rainfall and runoff depth,sediment loss and infiltration rate.The runoff depth and sediment loss for the four underlying surface plots increased in the order:maize<potato<abandoned farmland<bare land,but the order for the infiltration rate was on the contrary.The runoff depths in potato,abandoned farmland,and bare land plots increased by 58.95%,146.85%,and 261.48%,respectively,compared with that in the maize plot,and the losses of sediments increased by 50.45%,94.98%,and 240.06%,respectively,and the infiltration rates decreased by 5.68%,14.25%and 25.36%,respectively.A significant power function relationship between runoff depth and I10,I30,P×I10,P×I30 in maize,potato land and bare ground was found,but a linear function between runoff depth and these parameters in abandoned farmland existed.A similar trend as above was also found for amount of sediment loss.The infiltration rate decreased with the increase of rain intensity.Compared with potato,the characteristics of reducing runoff and sediment and increasing infiltration to a certain degree were observed in abandoned farmland and bare land,maize fields.