黄麻土工布覆盖对花岗岩红壤表土坡面侵蚀特性的影响

[目的]探究黄麻土工布覆盖条件下花岗岩红壤表土坡面侵蚀特性,为花岗岩红壤区坡面土壤侵蚀防治提供科学依据。[方法]通过室内模拟降雨试验,在2个坡度(5°和15°坡度)、3种密度(无覆盖,6 cm×6 cm及3 cm×3 cm网格)的黄麻土工布覆盖条件下,研究极端降雨条件下(90 mm/h)花岗岩红壤表土的坡面侵蚀特性,并观测径流系数、土壤侵蚀速率、泥沙颗粒变化规律及富集率等指标。[结果]坡面径流随降雨历时增加而增加,土壤侵蚀速率则相反,表明侵蚀过程是一个分离受限的过程。和对照组相比,黄麻土工布覆盖在不同试验条件下都具有明显的减流减沙作用。另外,由侵蚀泥沙的粒径分选规律可知,坡面土壤中的黏粒和粉粒大小的颗粒倾向于被优先选择性搬运,其结果致使坡面石英粗颗粒富集,在缓坡(5°)与高密度黄麻土工布覆盖条件下(3 cm×3 cm网格)尤为突出。坡面石英粗颗粒随降雨历时增加不断富集进一步增加了原位坡面的侵蚀抗性,产生了土壤侵蚀速率随降雨历时不断降低的现象。[结论]高密度黄麻土工布的覆盖能够有效地减流减沙,增加原位坡面抗蚀性,是一种有效的水土保持措施,在今后的土壤侵蚀防治和劣地恢复工作中应该被重视。

Effects of Jute Geotextile Covering on Erosion Characteristics of Granite Red Soil Slope

[Objective] The slope erosion characteristics in the granite red soil under different jute geotextile covering conditions were studied in order to provide a scientific basis for regional soil erosion control. [Methods] The slope erosion characteristics of granite red topsoil were investigated in terms of runoff coefficient, soil erosion rate, particle size distribution, and the enrichment ratio of eroded sediment through rainfall simulation experiments under the extreme rainfall intensity (90 mm/h) at slopes with 5° and 15° slope gradients and three different jute geotextile mulching conditions (uncovered, 6 cm×6 cm, and 3 cm×3 cm). [Results] The runoff increased with rainfall duration, in contrast to a decrease in the soil erosion rate, indicating a detachment-limited erosion process. Compared to the uncovered treatment, jute geotextile mulching obviously reduced runoff and sediment under different experimental conditions. Additionally, sorting of the eroded sediment revealed that the clay-and silt-sized particles along the slope were preferentially and selectively transported, resulting in the enrichment of quartz coarse particles on the slope surface, especially at the gentle slope (5°) and high jute geotextile coverage (3 cm×3 cm). With rainfall duration, the continuous enrichment of quartz coarse particles on the slope further enhanced the erosion resistance of in-situ slope, corresponding to the gradual decrease of soil erosion rate with rainfall duration. [Conclusion] High-density jute geotextile covering can effectively reduce the runoff and sediment, and can increase the erosion resistance of in-situ slope, suggesting its potential as an effective measure for soil erosion prevention and restoration.