1988——2015年三峡库区典型流域土壤侵蚀强度时空变化——以大宁河流域和梅溪河流域为例

Study on the temporal and spatial variation of soil erosion intensity in a typical watersheds of the Three Gorges Reservoir Area from 1988 to 2015: A Case Based on the Daning and Meixi River Watersheds

研究高程-坡度-岩性组合形成的不同土地类型的土壤侵蚀时空演变有重要意义。选取大宁河流域和梅溪河流域,以1988年、2000年、2010年和2015年4期遥感影像为数据源,借助RS和GIS技术,通过计算土壤侵蚀强度综合指数和冷热点分析,探讨不同土地类型的土壤侵蚀分布及演变规律,揭示其现实与理论意义。结果表明:(1)流域土壤侵蚀正在发生转型,即两流域各土地类型的土壤侵蚀强度指数随着时间的变化而逐渐降低,土壤侵蚀量由增到减,土壤侵蚀状况呈现好转趋势;(2)就两流域土壤侵蚀空间数量变化而言,土壤侵蚀演变热点区多为中山陡坡石灰岩区,且大宁河流域土壤侵蚀状况优于梅溪河流域;(3)两流域土壤侵蚀演变主要分布于中山陡坡石灰岩和砂岩区,在坡度和岩性上具有相似性,在海拔上具有差异性;在同一土壤侵蚀强度下,两流域不同土地类型土壤侵蚀演变具有一定的相似性;(4)土地类型影响土壤侵蚀分布,探究人类活动下不同土地类型与土壤侵蚀响应耦合关系将是下一步研究的方向。

Learning the evolution of soil erosion is significant to understanding the response of land types under combinations of elevation, slope and lithology. This study takes the Daning River and Meixi River watersheds in the hinterland of the Three Gorges Reservoir area as examples on the base of remote sensing data from 1988, 2000, 2010 and 2015. Having calculated indices of comprehensive soil erosion intensity and hot spot analysis with the help of RS and GIS techniques, we explore the distribution and evolution laws of soil erosion under the coupling of land use type, such as elevation, slope and lithology, and finally reveal its practical significance. The results show the following：（1） soil erosion in the watersheds is undergoing transformation. Over time, the index of soil erosion intensity decreased gradually, and soil erosion showed an improving trend in different land types between the two watersheds; （2） for the spatial change in soil erosion in the two watersheds, the hot spot area of soil erosion is mainly distributed in medium mountains, steep slopes and limestone areas, and the state of soil erosion in the Daning River Watershed is better than that in the Meixi River Watershed; （3） the soil erosion evolution in the two watersheds occurred in areas with medium mountains, steep slopes and limestone or sandstone, and is similar in slope and lithology, with differences in elevation. The reasion is similar in evolution among different land type areas; （4） land type can affect the distribution of soil erosion. The next research direction will be to explore the relationship between different land types and soil erosion responses under human activities.