基于土壤颗分粒径的泥沙来源量化研究

[目的]揭示黄土高原风水复合侵蚀区风力作用对水蚀的影响，为具有不同泥沙粒径侵蚀物质来源识别提供一种有效的方法支撑，也为风水复合侵蚀区侵蚀泥沙来源辨识提供理论参考。[方法]以覆沙模拟风蚀产物，基于室内模拟试验，研究覆沙之后坡面侵蚀发育特征，同时为了有效区分不同时刻侵蚀物质的来源，尝试采用泥沙粒径作为指纹因子进行侵蚀泥沙来源贡献的辨识。[结果]不同泥沙粒径组的3个指纹因子(粒径范围分别为：26.303～34.674,104.713～138.038,138.038～181.970μm)通过检验被确定为最佳指纹因子。基于最佳指纹因子，通过多元混合模型计算得出，在对同一土槽进行的3个阶段模拟降雨试验中覆沙层和黄土层的平均泥沙贡献率分别为48.2%和51.8%,24.8%和75.2%,6.8%和93.2%,且MAF>0.8。覆沙层的泥沙贡献率为第一阶段试验>第二阶段试验>第三阶段试验，计算结果与DEM相吻合。[结论]泥沙源地和侵蚀泥沙中的不同泥沙粒径组可作为指纹因子进行泥沙来源辨别，复合指纹法具有较好的适用性。

Identification of Sediment Sources Based on Grain Size of Soil

[Objective] The research aims to reveal the influence of wind action on water erosion in the wind-water composite erosion area of the Loess Plateau, provide an effective method support for the identification of erosion material sources with different sediment particle sizes, and a theoretical reference for the identification of erosion sediment sources in the wind-water composite erosion area. [Methods] The wind erosion products were simulated by sand covering. Based on the indoor simulation experiment, the development characteristics of slope erosion after sand covering were studied, and in order to effectively distinguish the sources of erosion materials at different times, the sediment particle size was used as a fingerprint factor to identify the contribution of erosion sediment sources. [Results] Three fingerprint factors of different sediment particle size groups(particle size range: 26.303～34.674 μm, 104.713～138.038 μm, 138.038～181.970 μm)were identified as the best fingerprint factors by testing. Based on the best fingerprint factors, the average sediment contribution rates of the sand-covered layer and the loess layer were 48.2% and 51.8%, 24.8% and 75.2%, 6.8% and 93.2%, respectively, and the MAF was greater than 0. 8 in the three stages of simulated rainfall experiments in the same soil bin. The contribution rate of sediment in the sand-covered layer was in the order: the first stage test > the second stage test > the third stage test, and the calculation results were consistent with the DEM. [Conclusion] Different sediment particle size groups in sediment source area and erosion sediment can be used as fingerprint factors to identify sediment sources, and the composite fingerprint method has good applicability.