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汶川大地震使龙门山区的山地生态系统遭受了极大的破坏.通过四川盆地西缘龙门山区典型亚热带森林两种样地(滑坡体和森林)的对比,采用布设微型径流仪的方式,分别对降水、植被盖度、坡度与径流及土壤侵蚀的关系进行了定量研究;进而采取分级比较的方式,对不同强度的土壤侵蚀进行了分析.结果显示:1)滑坡体比森林样地产生更多的累积径流量和累积侵蚀量,且两者间存在着显著性差异;2)滑坡体样地上,地表径流量及土壤侵蚀量与坡度呈显著正相关(P<0.01),而森林样地的地表径流量及土壤侵蚀量与坡度也有正相关关系,但是并不显著;3)单位面积内滑坡体比森林对照样地产生更多的地表径流和土壤侵蚀,且地表径流与土壤侵蚀量均呈显著正相关,滑坡体样地单位地表径流量的增加导致更严重的土壤侵蚀;4)土壤侵蚀分级比较表明,滑坡体“强烈”以上等级的土壤侵蚀量所占比例居多,而森林对照样地上超过80%土壤侵蚀属于“轻度”.即使在“轻度”等级中,滑坡体产生的土壤侵蚀量(202.35 t/km2)比森林样地(0.52 t/km2)也高出400倍以上.
Wenchuan earthquake caused great damage to the mountain ecosystem in Longmen Mountain.By comparing the two sample plots (landslide body and forest) in the typical subtropical forest in the Longmenshan area on the west edge of Sichuan Basin, Precipitation, vegetation coverage, slope and runoff and soil erosion were quantitatively studied.Furthermore, the grading comparison was used to analyze the soil erosion with different intensities.The results showed that: 1) Landslide mass produced more than the forest plots (P <0.01). However, there was a significant difference between them on the runoff and cumulative erosion of landslides. (2) Landslides, surface runoff and soil erosion were positively correlated with the slope (P <0.01) There was also a positive correlation between surface runoff and soil erosion and slope, but not significant. 3) Landslides within unit area produced more surface runoff and soil erosion than forestland, and both surface runoff and soil erosion And the increase of surface runoff of landslide-like units led to more serious soil erosion. 4) Comparison of soil erosion classification showed that landslide body While the proportion of soil erosion in the forest reference area is “mild.” Soil erosion amount of landslide body (202.35 t / km2) is higher than that of the forest The plot (0.52 t / km2) is also more than 400 times higher.