基于GIS的贡山县土壤侵蚀动态变化研究

GIS-based Study on the Dynamic Changes of Soil Erosion in Gongshan County

为了解贡山县土壤侵蚀状况,对后续水土保持建设提供科学支撑和理论基础,以GIS为平台,利用DEM、土壤、降雨量以及遥感影像等数据,运用RUSLE模型研究了贡山县1996年、2006年、2012年、2018年土壤侵蚀强度的时空动态变化特征。结果表明:(1)贡山县4个时期年均土壤侵蚀模数分别为1627.39,750.8,831.82,788.25 t/(km^2·a),整体呈现明显下降的趋势,降幅为51.56%,同时植被覆盖率上升12.9%,说明土壤侵蚀状况趋于好转。(2)空间上,贡山县土壤侵蚀强度以微度和轻度侵蚀为主,均占研究区侵蚀总面积89.4%以上,土壤侵蚀较为严重的区域是怒江和独龙江沿河两岸,主要发生强度及以上的侵蚀。(3)土壤侵蚀强度等级转移矩阵表明,微度侵蚀和轻度侵蚀的变化率较小,并且侵蚀程度较弱等级向侵蚀程度较强等级转换的比率均低于高侵蚀等级向低侵蚀等级转换的比率。(4)一般情况下,坡度越大的区域土壤侵蚀等级越高且研究区主要的土壤侵蚀坡度段在大于25°侵蚀坡上,是贡山县土壤侵蚀防治的主要区域。

To understand the status of soil erosion in Gongshan County and provide scientific support and theoretical basis for the subsequent soil and water conservation construction,based on GIS and the RUSLE model,the spatial-temporal characteristics of soil erosion in Gongshan County in 1996,2006,2012 and 2018 were studied by using DEM,soil data,rainfal us data and remote sensing images.The results showed that:(1)the average annual soil erosion modulus of four periods in Gongshan County were 1627.39,750.8,831.82,788.25 t/(km^2·a),respectively,and the overall trend presented a significant decline with the decreasing rate of 51.56%,while vegetation coverage increased by 12.9%;(2)spatially,soil erosion intensity in Gongshan County was mainly very slight erosion and slight erosion,accounting for over 89.4%of the total erosion area of the study area,the areas with more serious soil erosion distribute along the banks of the Nujiang River and the Dulong River;(3)the soil erosion intensity grade transfer matrix indicated that the rate of change of very slight and slight erosion is small,and the conversion mode is mainly conversion of high-grade to low-grade;(4)soil erosion tended to be serious with the increase of slope gradient;the main slope gradient susceptible for soil erosion in the study area is greater than 25°,which is the main area for soil erosion control in Gongshan County.