College of Geographic Science, Hunan Normal University, Changsha 410081, China.
Jiangxi Provincial Key Laboratory of Soil Erosion and Prevention, Nanchang 330029, China.
Int J Environ Res Public Health. 2023 Jan 24;20(3):2104. doi: 10.3390/ijerph20032104.
A deeper understanding of the rainfall-flow processes can improve the knowledge of the rain-driven erosional processes in coarse-textured agricultural soil. In this study, on the red soil slope farmland developed from weathered granite, a simulated rainfall experiment was conducted to study the characteristics of rainfall redistribution, the processes of surface-subsurface flow generation and prediction, and sediment production. Rainfalls with three intensities of 45, 90, and 135 mm h with a duration of 90 min were applied to the weathered granite red soil with the slope gradient of 10°. Under 45 mm h rainfall intensity, the output of rainwater was composed by subsurface flow and bottom penetration, accounting for 35.80% and 39.01% of total rainfall, respectively. When the rainfall intensities increased to 90 and 135 mm h, the surface flow became the main output of rainwater, accounting for 83.94% and 92.42%, respectively. Coarsened soil exhibited strong infiltration-promoting but poor water-storage capacities under light rainfalls. With an increased rainfall intensity, the surface flow coefficient increased from 19.87% to 92.42%, while the amount of subsurface flow and bottom penetration decreased by 1.3 and 6.2 L, respectively. For sediment production, the sediment concentration was raised from 1.39 to 7.70 g L, and D10, D50, and D90 increased by 1.50, 1.83, and 1.40 times, respectively. The content of coarse particles (>1 mm) in surface soil increased by 12%, while the content of fine particles (<0.5 mm) decreased by 9.6%. Under strong rainfalls, severe soil and water loss, coarsening soil surface, and large loss of fine particles became major problems. During rainfall, the subsurface flow and bottom penetration could be predicted well through quadratic equations of rainfall time, which transformed into time-dependent exponential functions after rainfall. The results provide a theoretical basis and data reference for soil erosion prevention and water management in coarse-textured agricultural lands.
深入了解降雨-水流过程可以提高对粗质地农业土壤中降雨驱动侵蚀过程的认识。本研究以风化花岗岩发育的赤红壤坡耕地为对象，进行了模拟降雨实验，研究了降雨再分配特征、地表-地下产流过程及其预测和泥沙产输规律。在坡度为 10°的条件下，用历时 90 分钟、强度分别为 45、90 和 135 mm h 的降雨对风化花岗岩赤红壤进行了模拟。在 45 mm h 的降雨强度下，坡面产流由地下径流和底孔流组成，分别占总降雨量的 35.80%和 39.01%。当降雨强度增加到 90 和 135 mm h 时，地表径流成为坡面产流的主要组成部分，分别占总降雨量的 83.94%和 92.42%。在小雨条件下，粗质地土壤表现出较强的入渗促进作用，但储水能力较差。随着降雨强度的增加，地表径流系数从 19.87%增加到 92.42%，而地下径流和底孔流的量分别减少了 1.3 和 6.2 L。就泥沙产输而言，泥沙浓度从 1.39 增加到 7.70 g L，D10、D50 和 D90 分别增加了 1.50、1.83 和 1.40 倍。表层土壤中粗颗粒（>1 mm）的含量增加了 12%，而细颗粒（<0.5 mm）的含量减少了 9.6%。在强降雨条件下，土壤和水流失严重、土壤粗化、细颗粒大量损失成为主要问题。在降雨过程中，通过降雨时间的二次方程可以很好地预测地下径流和底孔流，降雨结束后则转化为时间相关的指数函数。研究结果可为粗质地农业土壤的水土流失防治和水管理提供理论依据和数据参考。
