长江中上游坡耕地侵蚀产沙调控理论与实践

Theory and practice of sediment erosion control on slope cropland in upper and middle reaches of Yangtze River

针对以往长江中上游坡耕地水土流失研究中忽视壤中流,侵蚀产沙调控措施缺乏理论依据等问题,以人工模拟降雨实验为手段,基于细沟侵蚀临界坡长等理论,提出了既能截、排地表径流,又能排导壤中流的新型截水沟布局技术,改变了传统截、排水沟的设计思路。其原理是,在坡面截、排水沟的设计和布局中,以坡面细沟发育临界坡长为截水沟布设间距,阻断细沟发生,有效减少坡面侵蚀产沙和面源污染物;截获的坡面污染物通过梯级网络化调控体系排、蓄、集,经处理后可再次利用。该技术有效改善了坡耕地季节性干旱、缺肥以及河流水质问题,为长江中上游地区坡耕地侵蚀产沙调控提供了新思路。

Regulation of subsurface flow is often neglected in the study of soil and water loss on the slope cropland in the upper and middle Yangtze River, and measurements regarding sediment yield control is lack of theoretical basis. To solve these prob- lems, a new intercepting ditch, which not only can intercept, discharge surface runoff hut also discharge subsurface flow, was re- searched and developed based on critical slope length theory of rill erosion and artificial rainfall test, which changed the tradition- al designing idea of intercepting and draining ditch. The principles are： in the layout of intercepting and draining ditches, the ditches＇spacing is determined according to the critical slope length of rill erosion to prevent rill erosion and effectively reduce the slope erosion, sediment yield and surface non - point pollutants. The intercepted materials can be reused after draining, storing, collecting by cascade network. This technology can effectively improve problems of seasonal drought, fertilizer deficiency and wa- ter quality of slope cropland, providing new idea for the control of land erosion and sediment yield.