基于双土槽试验研究的黄土坡面侵蚀产沙过程

 定量分析梁峁坡面各侵蚀带之间侵蚀过程中的相互作用及其影响机理,将为坡面侵蚀预报模型的建立提供重要的理论基础。利用供沙土槽和试验土槽双土槽径流小区,研究不同上方汇流含沙量、不同降雨强度和不同地表面条件下的黏黄土陡坡面(15°)上方汇流汇沙,对坡下方侵蚀产沙过程的影响。研究结果表明:上方汇流汇沙对坡面侵蚀产沙过程有重要影响,上方来沙不但被径流全部搬运,而且上方来水在试验土槽引起了净侵蚀产沙量,坡面侵蚀现象为侵蚀-搬运过程占主导地位。对于疏松土和紧实土处理,上方汇流引起坡下方的净侵蚀产沙量,分别占试验土槽全部产沙量的31.1％-97.3％和45.1％-89.7％。上方汇流引起坡下方净侵蚀产沙量随降雨强度的增加而增加,同时受土壤容重和下垫面细沟侵蚀发展过程的综合影响。土壤容重影响坡面侵蚀的发生和发展,而坡面侵蚀产沙过程与细沟发育过程相对应。

Loess Hill Slope Erosion and Sediment Yield Process Using A Dual Box System

To quantify mutual influences and mechanisms of erosion processes about different erosion zones on loess ridge -mound-slope, which will provide important theoretic basis for constructing slope erosion prediction model. So a dual-box system of feeder box and test box with 15?gradient and clay loess was used to quantify effects of runoff and sediment from up-slope on down-slope erosion process under different sediment concentrations in up-slope runoff, rainfall intensities and soil surface conditions. The experiment results showed that runoff and sediment from up-slope have significant impacts on down-slope erosion process,sediment from up-slope was wholly transported, and runoff in up-slope caused the net sediment delivery (S) , sediment regime at down-slope is erosion-transported dominated. For the loose and compact surface treatments, the net sediment delivery (S) caused by up-slope runoff accounts for the total sediment delivery (S_ft) at sown-slope 31.7% to 97.3% and 45.1% to 89.7% separately. The net sediment delivery (S) increases with an increase of rainfall intensity. In addition, soil bulk density and rill erosion development have great effects on the sediment delivery (S) . Soil bulk density affects soil erosion process and the sediment delivery (S) during the run is associated with rill head-cut advance.