横坡垄作坡面径流冲刷条件下产流产沙研究

Study on Sediment Yield and Runoff under the Condition of Surface Erosion on Cross Slope Ridge Cropping

横坡垄作是一种广泛采用的耕作措施,具有较好的减流减沙的作用,但在地表径流冲刷下也会产生土壤侵蚀现象。本研究通过侵蚀槽模拟冲刷实验研究垄作措施条件下坡面土壤侵蚀过程。研究结果表明:①通过对照实验表明,横坡垄作措施条件下坡面的土壤侵蚀程度低。在10L/min的水流冲刷强度下,横坡垄作措施延缓了坡面初始产流时间,与裸地措施对比延缓时间增加了4.7倍。沟垄措施的减流减沙效果也较为显著,实验产流阶段,产流量和产沙量裸地措施分别是横坡垄作措施的1.1倍和1.4倍。②横坡垄作措施下土垄坡面侵蚀可分为蓄水阶段和产流阶段。由于沟垄沿坡面横向布设,地表径流进入沟道内下渗进入土壤需要一段时间,该阶段不产生侵蚀。当横向沟道内径流蓄满且来水速度超过下渗速度时,垄坡开始产生侵蚀,初期产生细沟,随后细沟迅速增大,拓宽,下切变深,汇流进入下一沟道,持续直到径流进入下一条沟道。产流前期产流产沙较小,但呈快速上升趋势。中后期,产流产沙均有所增加,后期产流、产沙达到最大之后(1.77L,30.53g),产流量趋于平稳,产沙量缓慢下降但整体小于裸地措施下的产流产沙量。

Cross slope ridge farming is a widely used farming measure,which can reduce runoff and sediment,but it will also produce soil erosion under the scouring of surface runoff.In this study,the erosion process of slope under ridge cultivation was studied by erosion trough simulation erosion experiment.The results show that:①the control experiment shows that the degree of soil erosion is low under the condition of cross slope ridge cultivation.Under the flow scouring intensity of 10L/min,the cross slope ridge cultivation measure delayed the initial runoff production time on the slope,and the delay time increased by 4.7 times compared with the bare land measure.In the experimental runoff yield stage,the runoff and sediment yield of bare land measures are 1.1 times and 1.4 times higher than that of cross slope ridge measures,respectively.②Soil ridge slope erosion under cross slope ridge cultivation can be divided into water storage stage and runoff production stage.As the furrows and ridges are arranged transversely along the slope,it takes a period of time for surface runoff to infiltrate into the ditch and soil,and there is no erosion at this stage.When the inner diameter of the transverse channel is full and the inflow velocity exceeds the infiltration velocity,the ridge slope begins to erode,and the rill is generated at the initial stage.Then the rill increases rapidly,widens,deepens the shear,and converges into the next channel until the runoff enters the next channel.The runoff and sediment yield in the early stage of runoff production is small,but it shows a rapid upward trend.In the middle and late stage,the runoff and sediment yield increased.After the runoff and sediment yield reached the maximum(1.77l,30.53g),the runoff tended to be stable,and the sediment yield decreased slowly,but it was less than the runoff and sediment yield under the bare land measures as a whole.