沂蒙山区土壤侵蚀时空变化及其驱动因素分析

Analysis of Temporal and Spatial Changes and Driving Factors of Soil Erosion in the Yimeng Mountainous Area

北方土石山区是我国土壤侵蚀最严重的地区之一,研究北方土石山区土壤侵蚀的时空变化对于水土保持规划及生态环境建设具有重要意义。以北方土石山区典型代表沂蒙山区为对象,基于地理信息系统(GIS)和遥感(RS)技术,利用修正版通用土壤流失方程(RUSLE)分析2000—2018年沂蒙山区土壤侵蚀的时空变化,并运用地理探测器对其驱动因素进行研究。结果表明:(1)沂蒙山区2000、2005、2010、2015和2018年5个时期的平均土壤侵蚀模数分别为5129.01、6661.76、6344.00、3493.23和5669.03 t·km^(-2)·a^(-1),整体呈现先升高后降低的趋势,同时土壤侵蚀强度向低等级转化趋势明显,说明土壤侵蚀状况趋于好转。(2)土壤侵蚀较为严重的区域主要分布在西部和北部,主要发生强烈及以上等级的侵蚀(≥5000 t·km^(-2)·a_(-1)),强烈以下等级的侵蚀(<5000 t·km^(-2)·a^(-1))主要分布在西南部和中东部。(3)各时期驱动因子的解释能力不同,土地利用类型起主导作用,对土壤侵蚀的解释力在42.52%~66.84%之间。土地利用类型为草地、地形地貌为中起伏中山、坡度位于15°~20°区间以及植被覆盖度处于0.4~0.6区间的地区是沂蒙山区土壤侵蚀防治的重点区域。

The rocky areas of northern China are among the most risky areas for soil erosion in China.The research on the temporal and spatial changes of soil erosion in these areas is of great significance to soil and water conservation planning and ecological environment construction.Based on GIS and RS technology,and by using the RUSLE model,this study takes the Yimeng Mountainous Area-a typical rocky area in northern China as the research area,to calculate the temporal and spatial changes of soil erosion in this area from 2000 to 2018.Through combining the data of topography,slope,altitude,vegetation,land,and rainfall,Geodetector was used to conduct quantitative attribution research on soil erosion.The results show that:(1)The average soil erosion modulus for the five periods were 5129.01,6661.76,6344.00,3493.23,and 5669.03 t·km^(-2)·a^(-1),respectively,in 2000,2005,2010,2015 and 2018.The tendency was to increase at first and then decrease,and the conversion mode was mainly conversion of high-grade to low-grade,indicating that the soil erosion of Yimeng Mountainous Area had been improved.(2)The soil erosion in the west and north of the study area was more severe,and the soil erosion intensities were mainly serious and above grades,while the areas with erosion intensity of less than serious grades were mainly located in the southwest and the central-east.(3)The explanatory ability of the driving factors was different in each period,and land-use type played the most prominent role,with its quantitative attribution to soil erosion ranging from 42.52% to 66.84%.The areas with the land-use type as grassland,with the topography as middle relief mountains,with the slope between 15°-20°,and with the vegetation coverage between 0.4-0.6,are the key parts for soil erosion control in the Yimeng Mountainous Area.