College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, 310058, China.
Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Hangzhou, 310058, China.
Environ Sci Pollut Res Int. 2019 Nov;26(31):32559-32573. doi: 10.1007/s11356-019-06486-z. Epub 2019 Oct 18.
The method of indoor artificial rainfall simulations was applied to compare the characteristics of runoff and sediment yield under different slope gradients (5°, 8°, 15°, and 25°) and rainfall intensities (30, 60, 90, 120, and 150 mm/h) for two kinds of different hillslopes with weathered granite and with exposed soils respectively from the laterite layer (L-soil) and sand layer (S-soil). The results show that the distribution of runoff yield significantly varied with soil types as the surface flow was predominant for L-soil while interflow was the main runoff form for S-soil. Both surface flow and sediment yield of L-soil was more than that of S-soil, and the changing trends for L-soil were more regular. The relationships between surface flow, sediment yield, and rainfall intensity can be expressed by power functions (R > 0.68). Interflow was positively related to slope gradient and displayed a single peak curve with the prolongation of runoff time. For S-soil, the surface flow increased with increasing slope gradient under light rainfall intensities but showed a decreasing trend under heavy rainfall intensities. Surface flow for L-soil showed a decreasing trend with increasing slope gradient under all rainfall intensities. The combined effects of slope gradient and rainfall intensity on runoff and sediment yield could be accurately described by linear correlation equations (R > 0.59). The impact of rainfall intensity on surface flow and sediment yield was much greater than that of slope gradient. Slope gradient presented a more significant effect on interflow. The eroded sediment consisted of a relatively higher content of clay, silt, and fine sand, which was approximately 1.26 times greater than the original soils. There was a grading limit of particle size (0.25 mm) for sediment transport. These results not only demonstrate the effects of rainfall intensity and slope gradient on sloping runoff and sediment yield but also provide valuable information for loss prediction and conservation of soil and water.
采用室内人工降雨模拟方法，对比分析了风化花岗岩和红土风化壳上的表土（L 土）和砂土层（S 土）在不同坡度（5°、8°、15°和 25°）和不同雨强（30、60、90、120 和 150mm/h）下的产流产沙特征。结果表明，产流特征受土壤类型影响显著，L 土以地表径流为主，S 土以壤中流为主要产流形式。L 土的地表径流和产沙量均大于 S 土，且 L 土的变化趋势更为规律。地表径流和产沙量与雨强之间的关系可用幂函数（R>0.68）表示。壤中流与坡度呈正相关，随产流时间延长呈单峰曲线变化。小雨强下，S 土的地表径流量随坡度增加而增大，大雨强下则呈减小趋势。各雨强下 L 土的地表径流量均随坡度增加而减小。产流和产沙的综合效应可通过线性相关方程（R>0.59）准确描述。雨强对地表径流和产沙的影响大于坡度，坡度对壤中流的影响较大。侵蚀泥沙中粘粒、粉粒和细砂含量相对较高，约为原状土的 1.26 倍。泥沙输移存在粒径分级界限（0.25mm）。这些结果不仅揭示了雨强和坡度对坡面产流产沙的影响，还为水土流失预测和防治提供了有价值的信息。
