暴雨条件下典型红壤区生物结皮坡面水土流失过程研究

为探明暴雨条件下典型红壤区生态恢复工程实施后生物结皮覆盖对坡面水土流失过程的影响,通过模拟降雨和室内分析试验,探究不同结皮覆盖度(0,20%,40%,60%,80%)坡面的土壤物理属性、水动力学特征及产流产沙过程。结果表明:(1)生物结皮覆盖下的红壤坡面土壤黏结力平均增加13.26%,土壤容重与穿透阻力平均分别减小8.97%和61.51%,表明生物结皮可有效增强红壤区坡面土壤稳定性,提升土壤抗蚀能力;(2)相较对照坡面,其余盖度坡面均可有效改善水流流态,坡面径流剪切力介于0.08~0.12。水流功率和断面单位能量分别减小12.22%~78.89%,8.32%~53.15%,坡面阻力系数增大1.09~1.50倍;(3)各生物结皮盖度坡面减流、减沙效益分别介于12.50%~78.76%,17.03%~94.31%,其中高覆盖度(80%)坡面土壤侵蚀强度较小。研究结果为有效防治红壤区坡面水土流失工作提供理论依据和实践参考。

Soil Erosion Process on Slope with Biological Soil Crusts Under Rainstorm in Typical Red Soil Region

In order to reveal the effect of biological soil crusts on process of soil and water loss on the slope after the implementation of ecological restoration project in typical red soil region under rainstorm, simulated rainstorm experiments and indoor experiments were conducted. In this research, the soil physical properties, hydrodynamic characteristics, runoff and sediment yield processes of slopes with different biological soil crusts coverages (0, 20%, 40%, 60% and 80%) were explored. The results showed that: (1) Under different coverages of biological soil crusts, the soil cohesion of red soil slope increased by 13.26% on average, while the soil bulk density and penetration resistance decreased by 8.97% and 61.51% on average, respectively, indicating that biological soil crusts effectively enhanced soil stability and soil anti-erodibility in red soil area. (2) Compared with the control slope, biological soil crusts effectively improved the flow pattern of slope, and the values of runoff shear stress ranged from 0.08 to 0.12. The water flow power and section unit energy reduced by 12.22%~78.89% and 8.32%~53.15%, respectively, and the slope resistance coefficient increased by 1.09~1.50 times. (3) The benefits of runoff reduction and sediment reduction on the slope surface of each biological crust coverage were between 12.50% and 78.76%, 17.03% and 94.31%, respectively, in which the soil erosion intensity of the slope with high coverage (80%) was the lowest. The results provided theoretical basis and practical references for effective prevention and control of soil and water loss on slope in red soil area.