降雨对土壤胶体释放与迁移的影响研究

降雨作为影响水土流失的主要因子,对表层土壤垂直侵蚀的影响没有得到应有的重视,选取长春地区具有代表性的阶地农田的粘壤土、河漫滩的细砂土和黄土台地的粉壤土为研究对象,用实验室土柱淋滤模拟实验定量研究了降雨对表层土壤中胶体释放与迁移的影响能力,并首次从土壤胶体的释放与迁移的角度解释了土壤的垂直侵蚀作用,从而为长春市水土流失和水土污染防治提供了参考依据.结果表明,土壤环境中降雨对土壤胶体的释放与迁移的影响即对表层土壤垂直侵蚀的影响是不容忽视的,其释放与迁移随降雨周期均具有"脉冲"的规律,在淋滤初期胶体具有比较明显的释放,后来胶体就降到一个较低恒定的水平.降雨通过引起土壤水动力条件和土壤溶液化学两方面变化影响土壤胶体的释放和迁移,初始降雨对土壤表面的侵蚀作用比持续的降雨具有更明显的作用.由于土壤矿物和机械组成不同,降雨对3种土壤的垂直侵蚀程度不同,释放量(垂直侵蚀损失量)为农土土柱>河土土柱>黄土土柱,且介于30-120mg/m~3之间.

Study on the Release and Migration of Soil Colloids with Rainfall

As the main factor affactting soil erosion,the infuence of rainfall on vetical erosion of topsoil have not be payed much attention to.In this experiment,clay loam,fine sand and silt loam collected from the farmland,floodplain and Loess platform in Changchun seperately were chosen for the matrix to study the impact of rainfall on the release and migration compacity of soil colloids through soil column leaching quantitily,and explained the vetical erosion of topsoil basing on the release and migration of soil colloids,which supplied reference basis for soil erosion and soil ＆ water pollution control in Changchun.The study shows colloids have a certain stability and mobility,so the release and migration of the three kinds of soil colloids vetical erosion of topsoil should not be ignored,and their release and migration have a"pulse"rule with rainfall cycles.At initial rainfall,the release of soil colloids is clear,then falls to a lower level.By changing soil hydrodynamic and hydrochemieal,rainfall infulence the release and migration of soil colloids.The initial rainfall has an obvious impact on soil erosion than continous rainfall,As different composition of soil mineral and mechnical,rainfall has an different vertial erosion on three kinds of soil,and the release amount namely vertical erosion loss amout between 30 and 120g/m~3 of the soil is farmland soil column>floodplain soil column>loess soil column.