基于RUSLE模型的南方丘陵山区土壤侵蚀研究

土壤侵蚀已成为世界范围内的生态环境问题,是水土保持的重要内容。本文基于GIS技术和RUSLE模型对南方丘陵山区4个主要省份——湖南、江西、浙江和福建的土壤侵蚀状况进行了定量研究,分析了土壤侵蚀空间分布特征以及与坡度、海拔间的关系。结果表明:研究区内年均土壤侵蚀量为2.46亿t/a,平均土壤侵蚀模数为421.81t/(km2?a);研究区水土保持状况良好,土壤侵蚀面积中,只有13.41%的面积存在着较高程度的侵蚀,局部区域表现为强烈侵蚀;空间上,湖南和江西的土壤侵蚀呈现块状分布,浙江和福建的土壤侵蚀则呈现出点状分布,湖南整体的水土保持状况不如其他3个省份;研究区内土壤侵蚀与坡度和海拔关系密切,微度侵蚀在各海拔和坡度等级下分布面积最大(均大于75%),强度以上的侵蚀分布面积很小(均小于1.5%),坡度15~25°和海拔200~500m的区域是研究区内土壤侵蚀最为强烈的区域。

Study of Soil Erosion in the Southern Hillside Area of China Based on RUSLE Model

Soil erosion is a major ecological and environmental issue globally. As an important content of soil and water conservation, soil erosion by water is a primary cause of soil degradation and is significantly threatening the environment. Based on GIS and RUSLE models, we conducted quantitative research on the quantity and spatial distribution of soil erosion in four provinces (Hunan, Jiangxi, Zhejiang and Fujian) comprising the Southern Hillside Area. In addition, relationships between the distribution characteristics of soil erosion and influencing factors (e.g. slope and elevation) were analyzed. We found that the annual amount of soil erosion was 246 million tons and the mean soil erosive modulus is 421.81t/km². Soil and water conservation good across the study area, and only 13.41% of the soil erosion area has a higher degree of erosion. Spatially, soil erosion in Hunan and Jiangxi were characterized by a block distribution; soil erosion in Zhejiang and Fujian were characterized by a point distribution. Soil and water conservation in Hunan were worse than the other provinces. The degree of soil erosion in the study area was closely related to slope and elevation. At different levels of slope and elevation, the slight erosion had the largest area (more than 75% of the area of soil erosion). Otherwise, the area of intense erosion and higher degree erosion was small compared to the slight soil erosion degree (less than 1.5% of the total). The slope 15~25° and elevation from 20~500m suffered the most intensive erosion.