【摘要】 区域表土粒度分布特征可反映该区环境特征,研究风水复合侵蚀区小流域内部表土粒度分布特征,可为探究风水两相侵蚀作用机理提供一定的理论依据。通过野外表土空间采样和室内测定,对地处风水复合侵蚀区的东柳沟流域的表土粒度分布特征及其可风蚀性进行研究,结果表明:东柳沟流域各种土地利用类型的表土粒径主要为细砂粒(50~250μm),体积分数为56.59%~86.65%,属于风沙土。流域不同土地利用类型表土粒度性质存在显著差异,草地、农地、灌木地的平均粒径(Mz)分别为77.60,81.66,87.85μm,颗粒级配较细,而沙地、河道的Mz分别为126.36,151.80μm,颗粒级配较粗;流域表土粒径大部分表现出正偏和窄峰,颗粒分布较集中。从流域上游到中游,表土粒度表现出明显的粗化现象,具体表现为:除河道外,上游各土地利用类型表土的Mz均显著小于中下游(P<0.05)。而在流域中游,除草地、河道之外,其他土地利用类型的Mz与沙地之间没有显著性差异。对流域表土的可风蚀性颗粒分析结果表明,自上游到中游的各土地利用类型的易风蚀颗粒含量显著增加,草地、农地、灌木、河道分别增加了44.4%,54.23%,48.84%,33.76%。结论表明,流域中游是表土粒度分布最复杂、风蚀作用最强烈的区域,同时也是风蚀与水蚀叠加作用最为频繁的区域。更多还原

【Abstract】 The distribution characteristics of topsoil particle size can reflect the regional characteristics of the district environment,research on the internal topsoil particle size distribution of small watershed in wind water erosion region could provide a theoretical basis for exploring the mechanism of water and soil erosion.By field sampling and laboratory determination of surface space,study on surface soil particle size distribution characteristics and wind-erosion possibilities of Dong Liu Gou basin which located in the area of wind-water erosion.The results were as follows:soil particle size of Dong Liu Gou watershed was mainly concentrated in the fine sand(50~250μm),volume fraction between 56.59% ~86.65%,belonging to aeolian sandy soil.There was a significant difference between the state of the size among different land use types.The Mz of grassland,farmland and shrub were 77.60μm,81.66μm and 87.85μm respectively,in which the particle size distribution was small.While the Mz of sandy land and river channel was large,which were 126.36μm and151.80μm respectively in coarse particle size.Most of the topsoil particle size showed a positive bias and narrow peaks,particle distribution is more concentrated.The rough phenomenon of the topsoil grain size has been shown obvious from upstream to middle reaches,specific performances:the Mzof the land use in the upper reaches was smaller than that in the middle and lower reaches except the river channel(P<0.05).While in the middle reaches,there was not significant difference between sandy soil and other land types in Mzexcept the grassland and river channel.After analysis the possibility of wind erosion of the topsoil in the watershed,we found that the erodible particles content significantly increased from upstream to the middle reaches,which were increased by 44.4%,54.23%,48.84%,33.76% in grassland,cropland,shrub,river,respectively.The conclusion showed that the middle reaches was the region where the topsoil particle size distribution was most complex and the wind erosion was most intense,and also and also the major area where wind and water erosion interacted.更多还原