基于GIS和USLE的钦江流域土壤侵蚀评估

Assessment of Soil Erosion in Qinjiang Watershed Based on GIS and USLE

在GIS和RS技术支持下，基于USLE模型对钦江流域土壤侵蚀进行了定量评估，并分析了不同海拔、不同坡度、不同土地利用类型下土壤侵蚀强度特征和规律。结果表明：（1）钦江流域年均土壤侵蚀模数为2608．87t／（km2·a），属中度侵蚀，远大于水利部规定的南方红壤丘陵区土壤允许流失量500t／（km2·a）的标准；（2）随高程升高，土壤侵蚀强度呈递减趋势。0～240m高程带是土壤侵蚀防治的重点区域。（3）随坡度增大，土壤侵蚀强度呈递减趋势。15。以下坡度带是钦江流域土壤侵蚀重点预防和治理区域。（4）不同土地利用类型的土壤侵蚀强度差异显著，旱地、草地和未利用地大部分处于强度侵蚀以上，是控制流域整体土壤侵蚀状况的关键土地利用类型。

Soil erosion intensity of Qinjiang watershed was evaluated based on USLE model by applying GIS and RS technology, and analyzing characteristics and disciplines of different elevation, slope and land use types. The results show that： （1） the average soil erosion rate in the whole year was 2 608.87 t/（km2 · a）, belonging to the moderate erosion, but this level was larger than the soil loss tolerance of 500 t/（km2 · a） in north red soil region ruled by the Ministry of Water Resources; （2） based on different altitude gradient in the research area, soil erosion intensity was in reverse proportion to the increase of the elevation gradient, so, the 0-240 m elevations was the key area of soil erosion prevention; （3） based on different slope gradient in the study area, soil erosion intensity was in reverse proportion to the increase of the slope gradient, the slope less than 15° was the key area of soil erosion prevention and management; （4） soil erosion intensity differ- ences under different land use types in study area were significant. Dry farmland, grassland and unused land mainly distributed in the serious erosion area, which was the key land use type to control the whole soil ero- sion intensity in watershed.