广西是我国喀斯特地貌分布主要区域之一,水土流失危害严重,利用第一次全国水利普查水土保持专项数据,以实际侵蚀调查单元和侵蚀地块为基础,统计和分析了广西侵蚀地块不同土地利用情况和地形特点以及土壤侵蚀空间分布规律。结果 表明:广西土地利用类型以为林地、耕地为主。整体地形崎岖,侵蚀地块破碎,平均坡长为35.60 m,平均坡度为18.49°。坡长、坡度空间分布规律基本一致,由西北向东南递减。随着坡度增加,各土地利用土壤侵蚀模数均呈先增大后减小的趋势,坡度临界值为25°～40°,坡长小于70 m时,土壤侵蚀模数随坡长增加不断增大,坡长对土壤侵蚀的影响稍大于坡度。广西土壤侵蚀强度以微度至轻度为主,各土地利用中耕地土壤侵蚀状况最严重,特别是15°以上的陡坡耕地对区域水土流失贡献最大。
Guangxi is one of the major regions with karst distribution, and the soil erosion in this region is very serious. According to the First National Water Census, we calculated and analyzed the characteristics of soil erosion in different land uses and topographies based on field erosion survey units and erosion plots. The results show that the forestland and cultivated land are the main land use types in Guangxi, the overall terrain is hilly and rough, and the erosion site is fragmentarily distributed in the area with an average slope length of 35.60 m and an average slope gradient of 18.49°; the spatial distribution of slope length and gradient is similar, decreasing from northwest to southeast. With the increase of slope gradient, the soil erosion modulus of each land use increases at first and then decreases, and the critical slope gradient is between 25°～40°. When the slope length is less than 70 meters, the soil erosion modulus increases with the slope length, and the influence of slope length on soil erosion is slightly larger than that of the slope gradient. The soil erosion intensity in Guangxi varies from mild to slight level. The soil erosion of the cultivated land is the most serious; especially the steep slope cropland above 15° has the biggest contribution to soil erosion in this region.
