基于普查样点的贵州省耕地土壤侵蚀空间分布

Spatial distribution of cropland soil erosion in Guizhou province based on sample data of the first national water census

坡耕地是贵州省土壤侵蚀的主要来源,严重的土壤侵蚀直接威胁区域粮食安全和生态环境可持续发展。为探讨贵州省耕地空间分布特征及土壤侵蚀强度,将第1次全国水利普查水土保持专项统计数据叠加到地貌类型分区上,对比分析贵州省耕地及其侵蚀强度的空间分布特征。结果表明:1)贵州省耕地占比空间分布格局明显,以印江、龙里、册亨一线为界,西多东少。2)随坡度增加,耕地土壤侵蚀模数呈相应增加趋势,在喀斯特区域表现的更明显;随坡长增加,耕地土壤侵蚀模数无明显变化趋势。3)全省耕地以中度侵蚀为主,占耕地面积的71. 17%;峰丛洼地和岩溶断陷盆地耕地侵蚀最为严重,剧烈侵蚀面积占比分别为34. 97%和15. 16%,因此这2个区应为贵州省水土保持防治的重点区域。研究结果可为贵州省水土保持规划及生态环境治理提供参考。

[Background] The Karst region of Southwest China is characterized with the fragile ecological environment. Guizhou province is suffering from high intensity of soil erosion and sloping cropland is the most vulnerable to soil erosion in this region. Soil erosion of sloping cropland in Guizhou province had been studied on a provincial scale,and the results are beneficial to providing a basis for promoting soil and water conservation in this region. The spatial distribution and erosion intensity of cropland are greatly affected by regional divisions by geomorphy and topographic factors;therefore,it is necessary to take regional divisions and topographic factors into consideration to determine key areas for ecological restoration in this region. [Methods]1) The digital map of regional divisions by geomorphy was created in ArcGIS 10. 2 software according to related articles. 2) By using SPSS 19. 0 software( Statistical Product and Service Solutions 19. 0),we explored the proportion of cropland area and the cropland soil erosion intensity in Guizhou province. 3) By using ArcGIS 10. 2 software,we built spatial distribution map of the proportion of cropland area and the cropland soil erosion intensity in Guizhou province. [Results]1) The spatial distribution pattern of cropland area proportion in Guizhou province was obvious,which decreased from west to east. The proportion of cropland in non-karst plateau was the lowest,on the contrary,it was the highest in western Karst plateau. 2) The cropland with slope gradient of 8-35° accounted for 91. 28% of the total cropland,and cropland with slope length > 25 m accounted for 97. 81%. With the increase of slope gradient,the soil erosion modulus increased correspondingly,especially in karst area;however,with the increase of slope length,the soil erosion modulus showed no obvious trend. 3) 71. 17% of the total cropland area in Guizhou province belonged to middle erosion( <200 t/km^2). The soil erosion in Peak-cluster depression and Karst fractured basin region were more serious with the acute erosion areas accounting for 34. 97% and 15. 16% of the total cropland,respectively. [Conculsions]On the whole,the Peak-cluster depression region and the Karst fractured basin region are the key areas for soil erosion control. These findings hold important implications for agricultural management,regional soil and water conservation and ecological management in Guizhou province.