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选取20°长期耕作紫色土坡面径流小区进行模拟降雨试验,分析坡面土壤的颗粒组成及其变异,比较侵蚀泥沙颗粒组成的过程变化及其与坡面土壤颗粒组成的差异。结果表明,紫色土具有较宽变幅的颗粒组成,0.002～0.25mm的颗粒含量最高,坡面土壤存在较大的异质性;降雨初期侵蚀泥沙中<0.05mm的单粒和微团聚体含量都在65%以上,富集率分别为1.30,1.44,整个泥沙中的富集率分别为1.12,1.10,是侵蚀泥沙的主体,这其中又主要是0.002～0.05mm的粉粒和微团聚体;泥沙中<0.01mm的物理性粘粒及>0.25mm的水稳性团聚体富集率分别为1.10,1.16;随着降雨时间延长,单个泥沙样的颗粒组成逐渐接近雨前表土。
The 20 ° long-term cultivation of purple soil slope runoff plot was simulated rain test, the particle composition and variation of slope soil were analyzed, the process variation of erosion sediment particle composition and the difference with the slope soil particle composition were compared. The results show that the purple soil has a wider amplitude of particle composition, the content of 0.002 ~ 0.25mm particles is the highest, the slope soil has a greater heterogeneity; the initial rainfall early erosion of <0.05mm single grain and microaggregate The content is above 65%, the enrichment rates are 1.30 and 1.44, respectively. The enrichment rates in the whole sediment are 1.12 and 1.10, respectively, which is the main body of erosion and sediment, of which the main is 0.002 ~ 0.05mm powder and Microaggregates; the sediment concentration of <0.01mm physical clay and> 0.25mm water-stable aggregates were 1.10 and 1.16, respectively; with the extension of rainfall time, the single sediment-like particle composition gradually approached the rain Topsoil.