ISSN 1000-3665 CN 11-2202/P

    夏藏滩滑坡轻度放牧和禁牧草地坡面土壤侵蚀特征

    Soil erosion characteristics on grassland slope under light grazing and closed grazing in Xiazangtan landslide

    • 摘要: 黄河上游巨型滑坡分布区正面临着草地退化、边坡水土流失等生态环境问题。因此,对黄河上游滑坡分布区不同条件草地坡面土壤侵蚀进行定量评价有助于解决相关的生态环境问题。文章选取位于黄河上游尖扎县的夏藏滩滑坡作为研究区,通过开展野外模拟降雨试验,探讨植被盖度(50%和80%)和降雨强度(0.42 mm/min和0.83 mm/min)对轻度放牧和禁牧草地坡面产流产沙过程及其特征的影响。结果表明:(1)增加植被盖度能有效延迟坡面初始产流时间以及降低坡面产流速率和产沙速率,植被盖度由50%增加到80%时,0.42 mm/min降雨强度下轻度放牧草地坡面初始产流时间延迟234.61%,平均产流速率和产沙速率分别降低29.46%和55.47%;(2)增大降雨强度会明显提前坡面初始产流时间以及提高坡面产流速率和产沙速率,降雨强度由0.42 mm/min增大到0.83 mm/min时,50%植被盖度的轻度放牧草地坡面初始产流时间提前40.91%,平均产流速率和产沙速率分别增大49.33%和28.86%;(3)草地禁牧可延迟坡面初始产流时间,降低坡面产流速率和产沙速率,0.42 mm/min降雨强度下,50%植被盖度的禁牧草地坡面相较于轻度放牧草地,初始产流时间延迟18.18%,平均产流速率和产沙速率分别降低10.39%和21.39%。研究结果可为黄河上游地区草地坡面土壤侵蚀评价及其防治提供参考和指导。

       

      Abstract: The giant landslide distribution area in the upper reaches of the Yellow River faces severe ecological and environmental challenges, including grassland degradation and slope soil erosion. Quantitative evaluation of soil erosion on grassland slope under different conditions in this region is therefore essential for addressing these issues. In this study, the effects of vegetation coverage (50% and 80%) and rainfall intensity (0.42 mm/min and 0.83 mm/min) on runoff and sediment yield process and its characteristics on slopes with light grazing and closed grazing grassland were investigated through simulated rainfall experiments in Xiazangtan landslide in Jianzha County, upper Yellow River. Results show that increasing vegetation coverage can effectively delay the initial runoff-yielding time and reduce both runoff yield and sediment yield rates on the slope. When vegetation coverage increased from 50% to 80%, the initial runoff-yielding time of light grazing grassland under 0.42 mm/min rainfall was delayed by 234.61%, while average runoff yield rate and sediment yield rate decreased by 29.46% and 55.47%, respectively. Higher rainfall intensity significantly accelerates the initial runoff-yielding time and increases both runoff yield and sediment yield rates. When the rainfall intensity increases from 0.42 mm/min to 0.83 mm/min, the initial runoff-yielding time of light grazing grassland with 50% vegetation coverage was 40.91% earlier, and the average runoff yield rate and sediment yield rate increase by 49.33% and 28.86%, respectively. Grassland grazing prohibition can delay the initial runoff -yielding time on the slope, and reduce the runoff yield rate and sediment yield rate. Under 0.42 mm/min rainfall, the initial runoff-yielding time of the closed grazing grassland with 50% vegetation coverage was delayed by 18.18% compared with the light grazing grassland, while the average runoff yield rate and sediment yield rate were reduced by 10.39% and 21.39% respectively. This study provides scientific basis and guidance for soil erosion evaluation and control of grassland slope in the upper reaches of the Yellow River.

       

    /

    返回文章
    返回