土体构型影响下红壤坡地壤中流和地表径流交互作用侵蚀机理

The interaction between subsurface seepage flow caused by solum configuration patterns and rainfall surface runoff is the major cause of serious soil erosion in cultivated slop land of red soil. Large outdoor soil water seepage lysimeter and artificial rainfall simulator in Jiangxi Eco-Science Park of Water and Soil Conservation will be used to study the process of the seepage of surface runoff and the formation of subsurface seepage flow in red soil slop in this research, which are both influenced by solum configuration patterns, adopting the methods including outdoor investigations, indoor experiments and outdoor monitoring. The process of rainfall- infiltration - runoff generation and the mechanism of sediment yield caused by soil erosion under the interaction between subsurface flow and surface runoff will be investigated in slop land of red soil by means of measuring the hydraulic characteristics of subsurface flow and overland flow and the process of sediment yield by slope erosion. According to the relationship between hydrodynamic process and soil erosion under the interaction of interflow and surface runoff，a soil erosion modle of red soil slop land will be established. The findings will provide theoretical basis for revealling the process and mechanism of soil erosion in red soil slope land and scientific basis for prevention and control of soil erosion in southern hilly area.

土体构型所引起的壤中流和降雨地表径流交互作用是引起红壤坡耕地侵蚀严重的重要原因。本研究借助于江西省水土保持科技园内的野外大型土壤水分渗漏和人工模拟装置，采用野外调查、室内试验和野外监测相结合的研究方法，研究土体构型影响下红壤坡面径流入渗和壤中流形成过程；通过测定壤中流和坡面水流的水力学特性及坡面侵蚀产沙过程，探讨红壤坡耕地降雨-入渗-产流过程和壤中流与地表径流交互作用下侵蚀产沙机理；根据壤中流与地表径流交互作用下的水动力过程与土壤侵蚀之间的关系，建立基于红壤坡地壤中流和地表径流交互作用的红壤坡耕地土壤侵蚀模型。研究成果将为揭示红壤坡耕地土壤侵蚀过程和机理提供理论基础，并为南方丘陵区水土流失防治提供科学依据。

土体构型引起的壤中流和地表径流交互作用是引起红壤坡耕地侵蚀严重的重要原因。本研究借助于江西省水土保持科技园内的野外大型土壤水分渗漏和人工模拟降雨装置，采用野外调查、室内试验和野外监测相结合的研究方法，研究土体构型影响下红壤坡面壤中流形成过程和侵蚀响应。在此基础上，构建了壤中流与地表径流交互作用的土壤侵蚀模型。研究结果发现：（1）土壤剖面构型对土壤的入渗和产流能力有明显影响。与均质土构型相比，具有耕层土壤剖面构型的土壤累积入渗量减小，入渗能力减弱，坡面壤中流和泥沙产生量较大。同时耕层深度对壤中流和泥沙产生量也具有显著的影响，耕作层厚度越深，壤中流占比越小，侵蚀强度越剧烈。HYDRUS可以较好地模拟土体影响下的红壤水分入渗和壤中流过程，模拟精度可达0.72以上。（2）地表覆盖和雨型对降雨产流产沙造成显著驱动差异。枯落物敷盖壤中流产流率最高，植草覆盖其次，裸露最低。长历时小雨强大雨量和长历时大雨强大雨量等连阴雨型是植草覆盖和枯落物覆盖主要的地表产流、壤中流和产沙类型。短历时大雨强小雨量暴雨类型是裸露地表产流和产沙的主要雨型。（3）壤中流产流具有明显的季节性。春季降雨-产流模式属于“低地表径流-高壤中流”，而夏季降雨表现出“高地表径流-低壤中流”模式。（4）不同深度壤中流对土壤侵蚀的作用不同。30 cm壤中流对地表土壤侵蚀具有抑制作用，而60 cm壤中流却对地表侵蚀具有促进作用。由此可知，壤中流的产生一方面减少了地表径流，另一方面使土壤抗蚀性减弱，其对土壤侵蚀的作用时促进还是抑制取决于量的多少。(5)构建的考虑壤中流和地表径流交互作用的土壤侵蚀模型可以较好的模拟研究区泥沙侵蚀量。该项目发表论文7篇，其中SCI论文2篇。