不同近地表水文条件下紫色土坡面土壤侵蚀过程研究

Soil Erosion Process on Hillslopes of Purple Soil Under Different Near-Surface Hydrological Conditions

采用模拟降雨试验,研究了自由下渗(free drainage)、土壤水分饱和(saturation)、壤中流(seepage) 3种近地面水文条件下紫色土坡面土壤侵蚀过程。结果表明,近地表水文条件会对紫色土坡面侵蚀过程产生重要影响。在地面坡度5°～15°条件下,当地表水文条件由自由下渗演变为土壤水分饱和时,坡面侵蚀量由1.31～2.02 g/(min·m^2)增加到1.83～5.50 g/(min·m^2);当地表水文条件由土壤水分饱和变为壤中流时,坡面侵蚀量达到4.40～16.41 g/(min·m^2)。土壤水分饱和条件下坡面侵蚀量是自由下渗的1.40～2.73倍;壤中流条件下坡面侵蚀量是自由下渗时的3.36～8.12倍,是土壤水分饱和时的2.40～2.98倍。同时,坡面坡度对紫色土坡面侵蚀过程有重要的影响。

Soil erosion processes on hillslopes of purple soil under three near-surface hydrological conditions of free drainage, saturation and seepage were studied by stimulated rainfall experiments. Results showed that near-surface hydrological conditions greatly affecting soil erosion processes on hillslopes of purple soil. At slope gradients from 5° to 15°, erosion rate from hillslopes shifted from 1.31-2.02 g/（min ·m^2） under free drainage to 1. 83-5. 50 g/（min ·m^2） under saturation condition; under seepage condition, erosion rate reached to 4.40-16.41 g/（min ·m^2）. Erosion rate under saturation condition was 1.40-2.7.3 times greater than that under free drainage; erosion rate under seepage condition was 3.36-812 times greater than that under free drainage and was 2.40-2.98 times higher than that under saturation condition. Meanwhile, slope gradient had a great impact on purple soil erosion processes.