丹江口市土壤侵蚀敏感性时空变化特征

土壤侵蚀是丹江口库区主要的生态问题之一，明确丹江口市土壤侵蚀敏感性的时空变化特征有助于深入认识丹江口库区的土壤侵蚀机理，也可为保护库区水环境提供依据。基于修正的通用土壤流失方程（RUSLE），结合丹江口市多山、地形破碎的地形特征，选择降雨侵蚀力、土壤可蚀性、地形起伏度、植被覆盖度、沟壑密度5个因子构建土壤侵蚀敏感性评价体系，借助ArcGIS 10.2平台，综合评价2012—2017年丹江口市土壤侵蚀敏感性，并分析研究区在不同下垫面要素下土壤侵蚀敏感性的空间分布特征。结果表明：丹江口市土壤侵蚀敏感性整体呈现南北高、中间低的态势，主要表现为轻度敏感和中度敏感，高度及以上敏感区仅占研究区总面积的13.53%；5年间丹江口市中度敏感、轻度敏感、不敏感区面积呈增加趋势，高度敏感和极敏感区面积呈下降趋势；疏林地和未利用地是研究区高敏感性土地利用类型；研究区土壤侵蚀敏感性随坡度增大呈先升高后降低趋势。研究成果可为丹江口市土壤侵蚀机理研究和水土保持及生态环境建设提供参考。

Spatial and temporal variations in soil erosion sensitivity in Danjiangkou City

Soil erosion is a major ecological problem in Danjiangkou reservoir area. Therefore, understanding the soil erosion mechanism of Danjiangkou reservoir area and conserving the water environment of the reservoir area is critical. Based on the revised universal soil loss equation(RUSLE) and the terrain characteristics of mountainous and broken terrain in Danjiangkou City, five factors, including rainfall erosivity, soil erodibility, topographic relief, vegetation coverage, and gully density were selected to develop a soil erosion sensitivity evaluation system. With the help of ArcGIS 10.2 platform, the soil erosion sensitivity of Danjiangkou City from 2012 to 2017 was comprehensively evaluated and the spatial distribution characteristics of soil erosion sensitivity in the study area under different underlying surface elements were analyzed. The results showed that the soil erosion sensitivity of Danjiangkou City was generally high in the northern and southern regions and low in the central region. Soil erosion sensitivity was characterized majorly as marginal and moderate sensitivity. Highly sensitive and extremely sensitive areas accounted for 13.53% of the total study area; during the five years, the moderately sensitive, marginally sensitive, and insensitive areas in Danjiangkou City showed an increasing trend, while the highly sensitive and extremely sensitive areas showed a downward trend; sparse woodland and unused land were highly sensitive land use types in the study area. The potential risk index of soil erosion in the study area increased initially and decreased later with the increase in slope. The research findings can serve as a reference for studying the soil erosion mechanism and developing strategies for the conservation of soil, water, and the overall ecosystem in Danjiangkou City.