College of Forestry, Guizhou University, Guiyang 550025, China.
Int J Environ Res Public Health. 2021 Dec 30;19(1):357. doi: 10.3390/ijerph19010357.
Soil erosion of sloped lands is one of the important sources of substantive sediments in watersheds. In order to investigate erosion characteristics of sloped lands during rainfall events in the Three Gorges Reservoir Area, erosion processes of purple and yellow soils under different slope gradients and rainfall intensities were studied by using a rainfall simulator. The results showed that the sediment concentration in runoff was closely correlated with rainfall intensity. The sediment concentration in runoff gradually rose to a peak with time, and then gradually declined and approach a steady rate during simulation rainfall events. The particle size distribution of surface soils before the rainfall was different from that after the rainfall. Soil erosion mainly resulted in the loss of fine particles of surface soil through runoff, and the fine particles of soil were enriched in sediments. Soil erosion rates were gradually increased with the slope gradient when the slope gradient was less than 10°, and significantly increased when the slope gradient was more than 10°. The slope factor of yellow soil could be fitted well to that calculated by the formula of Universal Soil Loss Equation (USLE). The trend of the slope factor of purple soil was similar to that of the slope factor that was derived from USLE. Therefore, the effect of slope gradients on soil erosion need to be further researched when USLE was applied to predict erosion in purple soil area.
坡地土壤侵蚀是流域内大量泥沙的重要来源之一。为了研究三峡库区降雨条件下坡地的侵蚀特征，采用人工模拟降雨装置，研究了不同坡度和雨强下紫色土和黄壤坡面的侵蚀过程。结果表明，坡面径流产沙浓度与雨强密切相关。在模拟降雨过程中，坡面径流产沙浓度随时间逐渐上升至峰值，然后逐渐下降并趋于稳定。降雨前和降雨后的地表土壤粒径分布不同。土壤侵蚀主要通过径流导致表层土壤细颗粒的损失，土壤细颗粒在泥沙中富集。当坡度小于 10°时，土壤侵蚀率随坡度梯度逐渐增加，当坡度大于 10°时，土壤侵蚀率显著增加。黄壤的坡度因子可以很好地拟合通用土壤流失方程（USLE）计算的坡度因子。紫色土的坡度因子趋势与 USLE 导出的坡度因子相似。因此，在应用 USLE 预测紫色土地区的侵蚀时，需要进一步研究坡度对土壤侵蚀的影响。
