粗颗粒土壤坡面侵蚀泥沙颗粒特征

Characteristics of Erosion and Sediment Particles on Coarse Texture Soil Slope

为揭示粗颗粒土壤坡面侵蚀机理,采用湖北通城县、江西赣县、福建长汀县、广东五华县4个样地的4种粗颗粒土壤(分别定义为TCA、GXA、CTA、WHA)进行室内模拟降雨试验,研究粗颗粒土壤坡面侵蚀过程及侵蚀泥沙颗粒组成的变化规律。结果表明:(1)4种土壤的地表径流随着降雨时间的增长呈现出先增加后递减并趋于稳定的规律;(2)4种土壤的侵蚀特征存在差异,土壤侵蚀速率表现为WHA>TCA>GXA>CTA;(3)4种土壤的侵蚀泥沙中颗粒分布百分比大小均为砂粒>黏粒>粉粒>砾石。不同土壤侵蚀泥沙富集率表现出明显差异;(4)水流功率与土壤侵蚀速率的相关性显著,用幂函数可以准确描述其关系。在表达式中引入土壤黏粒含量、砾石含量后模型更加可靠(D_(r)=0.001ω^(1.163)C_(l)^(-4.069),R^(2)=0.82;D_(r)=0.003ω^(1.149)G_(r)^(-1.934),R^(2)=0.84),提高了模型预测土壤侵蚀速率的精度,在实际应用中具有更广的适应范围与现实价值。

To reveal the slope erosion mechanism of coarse texture soil in China,we conducted the indoor rainfall simulation experiments with the four coarse texture soils(sieved soils of TCA,GXA,CTA,WHA from the counties of Tongcheng,Ganxian,Changting and Wuhua,China)to discussed the slope erosion process and sediment particle composition of coarse texture soil.The results showed:(1)The changes of surface runoff characteristics of the soils were significant.The surface runoff increased with the extension of rainfall time,and then decreased and tended to be stable.(2)The erosion characteristics of the soils were different,and the soil erosion rate decreased in the order of WHA>TCA>GXA>CTA.(3)The percentage of grain distribution in erosion sediment of the soils decreased in the order of Clay>Silt>Sand>Gravel.The enrichment ratio of different soils showed obvious difference.(4)There was a significant correlation between water flow power and soil erosion rate,and the relationship between them could be accurately described by power function.The model was more reliable after introducing the soil clay and gravel contents in the expression(D_(r)=0.001ω^(1.163)C_(l)^(-4.069),R^(2)=0.82;D_(r)=0.003ω^(1.149)G_(r)^(-1.934),R^(2)=0.84).The accuracy of predicting soil erosion rate was improved with a wider range of application and more realistic value in practice.