基于USLE的敖汉旗土壤侵蚀空间分异特征研究

The Characteristics of Spatial Differentiation of Soil Erosion of Aohan Banner Based on USLE

基于DEM、降雨、土壤调查等基础数据,在GIS和RS技术的支持下,运用USLE模型估算敖汉旗的土壤侵蚀量,探讨了不同土地利用、坡度和坡向下的土壤侵蚀强度空间分布差异性。结果表明:敖汉旗土壤侵蚀面积占研究区总面积的31.86%,年土壤侵蚀量达183万t,土壤侵蚀模数为697 t/(km^2·a),属轻度侵蚀区。耕地土壤侵蚀模数最大,为820 t/(km^2·a),占侵蚀总面积83.00%的耕地对侵蚀总量的贡献率高达97.61%,是水土流失防治的重点;土壤侵蚀模数和侵蚀量随坡度的增大均呈现先增大后减小的趋势,二者最大值均出现在8°~15°;占研究区侵蚀总面积38.62%的坡度范围(5°~25°)对土壤侵蚀总量贡献率高达65.39%,是土壤侵蚀发生的主要坡度区域;阳坡土壤侵蚀较阴坡严重,二者对侵蚀量的贡献率分别为47.36%和45.59%,与土地利用、坡度相比,坡向对土壤侵蚀空间差异性的影响不显著。

The paper estimated the amount of soil erosion of Aohan Banner by using USLE model and studied the spatial differentiation of soil erosion intensity under the different conditions of land use,slope and slope direction with the support of GIS and RS technology based on the basic data of DEM,precipitation and soil survey. The outcomes show that the soil erosion area of Aohan Banner makes 31.86% of the total studied area,the annual total amount of soil erosion is 183×104 t and soil erosion modulus is 697 t/( km2·a),belonging to mild erosion region. The arable soil erosion modulus is the maximum 820 t/( km2·a) and the contribution rate to soil erosion of cultivated land which makes up 83.00% of the total eroded area is 97.61% where is the key place for soil and water loss prevention and control. The soil erosion modulus and soil erosion quantity show the trend of first increase and then decrease along with the increase of slope and the maximum value of the two all shows within 8° ～ 15°. The contribution rate to soil erosion of slope( 5° ～ 25°) which makes up 38.62% of the total eroded area of the studied area is 65.39% where is the main source area of soil erosion. The soil erosion of sunny slope is serious comparing with that of the shady slope and the contribution rate to soil erosion of the two is 47.36% and 45.59% respectively. The influence of slope direction to the spatial differentiation of soil erosion is insignificant comparing with land use and slope.