鄂尔多斯市1988-2000年土壤水力侵蚀与土地利用时空变化关系

土地利用是引起土壤侵蚀的重要驱动过程。基于1988年和2000年TM影像数据和气候、土壤、植被及DEM等数据，运用通用的土壤流失预报方程（RUSLE），对鄂尔多斯市1988-2000年间的土壤水力侵蚀进行定量估算，揭示期间水力侵蚀的时空变化特点，并对土地利用类型与土壤侵蚀的关系进行分析。结果显示：1988-2000年间，研究区土壤水力侵蚀时空变化较为明显。时间变化上侵蚀强度明显减弱，除了微度侵蚀从53.16%剧增至81.24%以外，中度、强度、极强度和剧烈侵蚀类型均有较大幅度的下降；空间变化亦很明显，2000年与1988年相比，剧烈侵蚀只有准格尔旗东南部还有少量分布，强度侵蚀和极强度侵蚀主要分布在准格尔旗境内。土地利用方式对土壤侵蚀有明显的影响，高覆盖草地和水域的土壤侵蚀强度较小。此外，不同土地利用类型的平均土壤侵蚀模数和土壤强度指数均有大幅度的下降。其中未利用地的下降幅度最大（68.14%），其次为低覆盖度草地（64.09%），耕地的下降幅度最小（49.62%）。研究结果表明，鄂尔多斯土壤水力侵蚀治理的重点区域是东北部，改变土地利用方式，增加水土保持工程措施，加强采矿迹地的修复重建等是有效防治土壤水力侵蚀的重要措施。

The Temporal and Spatial Variability Relationship of Soil Water Erosion and Land Use Type in Ordos during the Period of 1988-2000

Land use is an important cause of soil erosion process. Based on the TM image data, climate, soil, vegetation and DEM data etc. in 1988 and 2000, this paper used the Revised Universal Soil Loss Equation (RUSLE) to estimate the amount of soil water erosion of Ordos city which was located in the farming-grazing transitional zone during the period of 1988 - 2000 and revealed the characteristics of temporal and spatial variability of soil water erosion and then analyzed the relationship between land use types and soil water erosion. The results showed; in 1988 the average soil erosion modulus was 2772. 07 t/(km~2 · a) and in 2000 the average soil erosion modulus was 1101. 06 t/(km~2 · a). During the 12 years, the change of temporal and spatial variability of soil water erosion was more obvious. The erosion intensity decreased significantly, besides the area of slight erosion sharply increased from 53. 16% to 81. 24% , the area of remaining soil erosion types had sharp fall. Spatial variation was also very obvious. Compared with 1988, severe erosion was only distributed in the southeastern part of Jungar Banner and strong erosion and very-strong erosion were mainly distributed in the Jungar Banner in 2000. The land use type had a significant impact on soil erosion. High-coverage grassland and water bodies had small contribution to soil water erosion. Besides that the average soil erosion modulus and soil erosion intensity index of the land types had highly declined. The unused land had the biggest drop which was 68. 14% and next was the low-coverage grassland which dropped by 64. 09%. The smallest decline was the farmland which was 49. 62%. The key region of soil water erosion control was the northeastern part and the effective control measures of soil water erosion were to change the patterns of land use, increase the engineering measures of soil and water conservation, improving the area of high-coverage grassland and enhance the reparation and reconstruction of mining slash etc.