贺兰山低山区土壤抗蚀性的空间差异性

Spatial Variations in Soil Erosion Resistance in Low Elevation Areas of Helan Mountains

[目的]对宁夏回族自治区贺兰山低山区表层土壤抗蚀性空间变化特征进行分析,为该区的环境保护、生态建设及生态治理提供科学依据。[方法]通过对贺兰山低山区不同海拔表层土壤进行野外取样与室内测定分析,运用统计学方法筛选出表层土壤可蚀性关键因子,构建贺兰山低山区土壤抗蚀性综合评价模型,并采用该模型对贺兰山海拔1300~1800 m区域土壤抗蚀性强弱进行研究。[结果]①土壤含水率、总孔隙度、黏粒、粉粒含量以及分形维数与海拔具有显著正相关关系,容重和砂粒含量与海拔为显著负相关关系,这7个土壤因子均为中度、弱度变异性,可初步选为土壤可蚀性影响因子;②土壤孔隙特征类与土壤粒径类影响因子之间存在明显显著相关并相互影响,因子之间存在明显的信息重叠现象;③通过构建土壤抗蚀性综合评价模型,随着贺兰山海拔高度由1800 m降低为1300 m,其土壤抗蚀性由强到弱,且与海拔呈显著正相关关系。[结论]贺兰山低山区土壤性质和土壤抗蚀性与海拔显著相关,可通过制定专门的保护措施与土壤修复方案改善土壤的结构与质量,加强土壤抗蚀性,促进该区域生态建设和增强水土保持功能。

[Objective]The spatial variations in surface soil erosion resistance in the low elevation areas of the Helan Mountains in Ningxia Hui Autonomous Region were analyzed to provide useful references to environmental protection and ecosystem management and construction in this ecologically vulnerable area.[Methods]A field survey and laboratory measurements of the surface soil samples collected across the low elevation area of the Helan Mountains were conducted.The key factors determining surface soil erodibility were identified and a comprehensive evaluation model of soil erosion resistance was constructed to analyze the soil erosion resistance in the areas 1300-1800 m in elevation.[Results]①The soil moisture content,total porosity,clay,silt content,and fractal dimension had significantly positive correlations with elevation and the bulk density and sand content had significantly negative correlations with elevation.These seven soil factors showed variability at weak or moderate levels.Therefore,they can be selected as the influencing factors of soil erodibility.②Significant correlations between the influencing factors of soil porosity and soil particle size were found,suggesting information redundancy.③The comprehensive evaluation model of soil erosion resistance suggested that soil erosion resistance weakened as the elevation decreased from 1800 to 1300 m,showing a significantly positive correlation with elevation.[Conclusion]The soil properties and soil erosion resistances were significantly related to elevation in the low elevation area of the Helan Mountains.Special protection measures and soil remediation programs should be formulated to improve the soil structure and quality,strengthen soil erosion resistance,and enhance the functioning of soil and water conservation.