基于RUSLE模型的安徽郎溪县土壤侵蚀时空变化及其影响因素分析

Temporal and spatial changes of soil erosion and its influencing factors in Langxi County,Anhui Province based on RUSLE model

为配合正在安徽省郎溪县开展的1∶50000土地质量地球化学调查评价项目,给郎溪县土地质量地球化学调查与评价提供丰富的遥感层面数据,同时为地方政府对土地利用规划、农作物种植、农业林业生产管理、地质灾害治理和生态环境保护等方面提供数据支撑,本文基于RUSLE模型、GIS与RS技术获取了郎溪县2010年、2020年土壤侵蚀空间分布及2011—2020年的平均土壤侵蚀空间分布,探究在强降水事件及长时序、常态化下郎溪县土壤侵蚀的时空变化及其主要影响因素。结果表明:郎溪县土壤侵蚀等级较高区域主要集中于东北侧和西南侧丘陵山区,2010年平均土壤侵蚀模数为549.148 t/(km^(2)·a),2020年为704.924 t/(km^(2)·a),土壤侵蚀减弱区域占全县面积的9.3%,土壤侵蚀增加区域占全县面积的44.0%,因此,2020年强降水事件对郎溪县土壤侵蚀影响显著,且土壤侵蚀加剧的主要影响范围集中于微度侵蚀和轻度侵蚀层面,并多发于高植被覆盖且低地势耕地区域。2011—2020年间的平均土壤侵蚀模数为443.923 t/(km^(2)·a),相对于2010年,土壤侵蚀强度整体呈减弱趋势,其中,土壤侵蚀减弱区域占全县面积的14.1%,土壤侵蚀增加区域仅占全县面积的3.3%,且土壤侵蚀加剧区域主要分布于丘陵山区。

In order to serve the 1∶50000 land quality geochemical survey and evaluation project being carried out in Langxi County,Anhui Province,provide it with rich remote sensing data,and give data support to the local government in land use planning,crop growing,agricultural and forestry production management,geological hazard control and ecological environmental protection,etc.,based on RUSLE model,GIS and RS technology,we obtained the spatial distribution of soil erosion in 2010 and 2020 and the average spatial distribution of soil erosion from 2011 to 2020 in Langxi County,and explored the temporal and spatial changes of soil erosion and its main influencing factors that are premised on heavy precipitation events,long time series and normal conditions.The results show that high-grade soil erosion is mainly concentrated on the northeastern and southwestern sides of hilly and mountainous areas,the average soil erosion modulus was 549.148 t/(km^(2)·a)in 2010 and 704.924 t/(km^(2)·a)in 2020,the area with reduced soil erosion accounted for 9.3%of the whole county area and the area with increased soil erosion accounted for 44.0%of the county area.Therefore,heavy precipitation events in 2020 had a significant impact on soil erosion in Langxi County,and the increased soil erosion was concentrated at the level of micro and mild erosion,mostly in the cultivated land area with high vegetation coverage and low terrain.From 2011 to 2020,the average soil erosion modulus was 443.923 t/(km^(2)·a).Compared with 2010,the soil erosion shows a decreasing trend as a whole,the area with reduced soil erosion accounted for 14.1%of the county area,while the area with increased soil erosion accounted for only 3.3%of the county area,mainly in the hilly and mountainous areas.