Theory and practice of sediment erosion control on slope cropland in upper and middle reaches of Yangtze River
ZHANG Pingcang;DING Wenfeng;Soil and Water Conservation Research Institute,Yangtze River Scientific Research Institute;
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 problems,a new intercepting ditch,which not only can intercept,discharge surface runoff but also discharge subsurface flow,was researched and developed based on critical slope length theory of rill erosion and artificial rainfall test,which changed the traditional 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 water quality of slope cropland,providing new idea for the control of land erosion and sediment yield.