福贡县土壤侵蚀时空变化及其影响因素分析

Spatiotemporal Changes and Influencing Factors of Soil Erosion in Fugong County Based on GIS

开展福贡县土壤侵蚀时空动态变化分析,对当地的水土流失防治和国土空间规划具有重要意义。研究基于降雨、土地利用、土壤和植被覆盖度等数据,采用GIS技术和RUSLE模型分析了福贡县2002年、2010年和2018年的土壤侵蚀时空变化和影响因素。结果表明:(1)福贡县土壤侵蚀强度主要以微度侵蚀和轻度侵蚀为主;2002—2010—2018年平均土壤侵蚀模数不断下降,微度侵蚀面积不断增加,福贡县土壤侵蚀状况呈现改善趋势;(2)福贡县土壤侵蚀严重区主要分布在怒江两岸,近16 a福贡县74.73%以上的区域土壤侵蚀强度未发生改变,整体好转,表明退耕还林等工程实施对抑制土壤侵蚀强度有一定效果;(3)土地利用类型是福贡县土壤侵蚀的主要影响因子;各因子解释力的大小依次为:土地利用类型、植被覆盖度、年均降雨量、海拔、坡度。海拔1005~1523 m、坡度>35°、年均降雨量1482~1671 mm、植被覆盖度<0.3、土地利用类型为未利用地的区域被识别为高风险侵蚀区。结合福贡县实际,坡耕地应为福贡县土壤侵蚀治理的重点区域。

Carrying out the analysis of the temporal and spatial dynamics of soil erosion in Fugong County is of great significance to the local soil erosion control,ecological environment construction,and land and space planning.Based on rainfall,land use,soil and vegetation coverage data,GIS technology and the RUSLE model were used to calculate the spatiotemporal changes of soil erosion in Fugong County in 2002,2010 and 2018,and to analyze the influencing factors.The results show that:(1)the soil erosion intensities in Fugong County were mainly micro-erosion and light-erosion which accounted for more than 91%of the total area of the study area;the average soil erosion modulus from 2002 to 2010 to2018 continued to decline,the slightly eroded area continued to increase,and the soil erosion situation in Fugong County was showing an improvement trend;(2)the severe soil erosion areas in Fugong County mainly distributed on both banks of the Salween River;in the past 16 years,more than 74%of the areas in Fugong County had not changed the soil erosion intensity;the overall improvement had shown that the implementation of projects such as returning farmland to forests had a certain effect on suppressing soil erosion intensity;(3)land use type was the dominant factor on the spatial distribution of soil erosion in Fugong County;the explanatory power of each factor decreased in order:land use type>vegetation coverage>average annual rainfall>Altitude>slope;the q value of the land use type factor was the largest,which was the dominant factor in the spatial distribution of soil erosion in Fugong County;areas with an altitude of 1005~1523 m,a slope of>35°,an average annual rainfall of 1482~1671 mm,a vegetation coverage of<0.3,and an unused land use type were identified as high-risk erosion areas.Based on the actual situation of Fugong County,sloping farmland should be a key area for soil erosion control in Fugong County.