锡林郭勒草地景观系统土壤容重空间变异及其与风蚀的关系

Landscape Scale Spatial Variation of Soil Bulk Density and Its Relationship with Wind Erosion in Xilinguole Grassland

[目的]探究锡林郭勒草地在景观尺度上土壤容重空间分布规律及其与风蚀的关系,为有效进行草原风蚀防治提供理论参考。[方法]对锡林郭勒草原不同地形和土地利用条件下土壤容重的空间变异性进行调查分析,主要采用环刀法、吸管法、TOC法测定土壤容重、机械组成和有机碳含量。[结果]锡林郭勒草原土壤容重呈现中等空间变异性;容重随地形变化在轻牧区表现为:迎风坡>背风坡>平地,而在中牧和重牧区的变化与之相反,且海拔与容重呈负相关性;在同样地形条件下,不同土地利用容重变化规律为:重牧区>耕地>中牧区>轻牧区>禁牧区。[结论]研究区土地利用类型是影响容重最主要的因素。容重与风蚀速率呈现明显的负相关性,容重可作为评估本区域风蚀发生与影响强度的一个重要参考指标。

[Objective] Identifying the spatial variation of soil bulk density at landscape scale, and the relationship between bulk density and wind erosion in Xilinguole grassland in order to provide references for wind erosion control in grassland.[Methods] The spatial variation of soil bulk density in different topographies and land uses in Xilinguole grassland was investigated and analyzed. Soil bulk density, mechanical components and organic carbon were measured using cutting ring, straw method and TOC method, respectively.[Results] Soil bulk density had moderate spatial variability. In terms of topography, bulk density in lightly grazed grassland followed：windward 〉 leeward 〉 flat area, vice versa the rank was reversed in moderately and heavily grazed grasslands. Elevation had negative correlation with bulk density. Bulk densities of different land uses ranked as：heavily grazed grassland 〉 arable land 〉 moderately grazed grassland 〉 lightly grazed grassland 〉 ungrazed grassland.[Conclusion] Land use is the main factor affecting soil bulk density in the study area. Bulk density and wind erosion rate showed high negative correlation, hence it can be used as an important reference index to assess the occurrence and intensity of wind erosion in this area.