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全球变化引起了一系列环境效应,土壤侵蚀是全球变化最为敏感环境效应之一。选择生态极其脆弱区小江流域作为研究对象,通过遥感影像和雨量站点获取3期土地利用和降雨变化信息,结合区域基础地理信息数据,利用通用土壤流失方程(USLE模型)对该区域土壤侵蚀对土地利用和降雨变化的响应进行了分析。研究表明:(1)降雨量在1981～1990年为降雨量较小年份,1991～2000年为降雨量较大时间段,2001～2005年降雨量开始急剧减少;(2)1987、1995和2005年的平均侵蚀量分别为:70.58、80.08和79.81t/(hm2.a),中度侵蚀以上面积分别占总面积的29.92%、33.83%和33.18%,其中极强度侵蚀分别占9.15%、12.81%和12.63%;(3)在分布特征上,强度侵蚀和极强度侵蚀主要分布在小江流域的中下游地段。极强度侵蚀主要分布在中海拔区域(1 600～2 800m),所占的比例呈持续下降的趋势,但在高海拔区域,极强度侵蚀呈增加趋势;同时,极强度侵蚀集中分布在高坡度段(>35°)上,占其面积的85%以上,且呈持续增加趋势,在中坡度段(15°～35°)上,极强度侵蚀呈现明显的减少趋势。USLE模型可以较好的反映出全球变化条件下土壤侵蚀效应,为合理开发土地资源和人类经济活动提供科学依据。
Global change has caused a series of environmental effects, and soil erosion is one of the most sensitive environmental effects of global change. Based on the data of regional basic geographic information and the common soil loss equation (USLE model), this paper selects the soil erosion of the region as the research object, obtains the information of three land use and rainfall changes from remote sensing images and rainfall sites, Use and response to rainfall changes were analyzed. The results show that: (1) The rainfall was from 1981 to 1990 with a small amount of rainfall, and from 1991 to 2000, it was a period of heavy rainfall. Rainfall began to decrease sharply from 2001 to 2005; (2) In 1987, 1995 and 2005 The average annual erosion rates were 70.58, 80.08 and 79.81 t / (hm2.a), respectively. The area above the moderate erosion accounted for 29.92%, 33.83% and 33.18% of the total area respectively, of which the extremely intensive erosion accounted for 9.15% 12.81% and 12.63% respectively. (3) On the distributional characteristics, the intensity erosion and extremely intense erosion are mainly distributed in the middle and lower reaches of the Xiaojiang River Basin. The extremely intensive erosion mainly distributes in mid-altitude area (1 600 ~ 2 800m), the proportion of which shows a continuous downward trend, but in the high-altitude area, the intense erosion shows an increasing trend; meanwhile, the extremely intensive erosion concentrates In the high slope section (> 35 °), it accounts for more than 85% of its area, and shows a continuous increasing trend. At the middle slope section (15 ° ~ 35 °), the intense erosion shows a significant decreasing trend. The USLE model can better reflect the soil erosion effect under the global change conditions and provide a scientific basis for the rational development of land resources and human economic activities.