复合指纹法定量示踪泥沙来源——以南流江上游子流域为例

Quantitative Tracing of Sediment Sources in the Nanliu River Basin by Composite Fingerprint Method

[目的]为研究桂南沿海丘陵台地自治区级水土流失重点治理区南流江流域内沉积泥沙来源,[方法]故以南流江上游泥沙关系变化剧烈的大会坡流域作为研究区,根据流域要素特征划分沉积岩和火成岩两种潜在物源类型,利用统计学方法筛选出最优指纹因子组合,运用多元混合模型定量分析泥沙源地的侵蚀产沙率。[结果]从33个指纹因子中筛选出6个最优指纹因子组合(K_(2)O_(3)、B、Cu、Pb、pH、Sb),总判别率高达83.1%;利用多元混合模型(拟合优度值达90.04%)得出大会坡侵蚀泥沙来源地贡献率分别为:沉积岩表层土壤占77.04%,火成岩表层土壤占22.96%。[结论]沉积岩表层土壤区是南流江流域土壤侵蚀最为严重的岩性类型。上述结果表明,沉积岩表层土壤应该是后续南流江上游水土保持关注的重点区域。

In order to study the source of sediment in the Nanliu River Basin,the key control area of soil erosion in hilly plateau autonomous region of southern Guangxi.[Method]The Dahuipo River Basin,where the sediment relationship in the upper reaches of the Nanliu River has changed dramatically,was taken as the research area,and two potential provenance types,sedimentary rocks and igneous rocks,were divided according to the characteristics of basin elements,and the optimal combination of fingerprint factors was screened by statistical method,and the erosion and sediment yield of sediment sources were quantitatively analyzed by multivariate mixed model.[Result]Six optimal fingerprint factor combinations(K_(2)O_(3),B,Cu,Pb,pH,Sb)were selected from 33 fingerprint factors,and the total discrimination rate was as high as 83.1%.By using the multivariate mixed model(goodness of fit reached 90.04%),the contribution rates of erosion sediment sources on the slope are as follows:the top soil of sedimentary rocks accounts for 77.04%,and the top soil of igneous rocks accounts for 22.96%.[Conclusion]The surface soil area of sedimentary rocks is the most serious lithologic type of soil erosion in the Nanliu River Basin.The above results show that the surface soil of sedimentary rocks should be the key area of soil and water conservation in the upper reaches of the Nanliu River.