锡林郭勒草原土壤碳氮分布及其影响因素研究

Study on Soil Carbon and Nitrogen Distribution and Its Influencing Factors in Xilingol Steppe

为阐明锡林郭勒草原土壤碳、氮空间分布特征及其环境影响因素,本研究以锡林郭勒不同生境草原土壤为研究对象,分析草原土壤碳、氮含量的空间分异规律,探究草原环境气候因子变化趋势及其对土壤碳、氮动态的驱动关系。结果表明:(1)锡林郭勒草原土壤有机碳含量平均为1.46%,表现为草甸草原>典型草原>盐生草甸>沙地典型草原>荒漠草原;土壤全氮含量平均为0.26%,表现为草甸草原>典型草原>沙地典型草原>荒漠草原>盐生草甸;(2)不同类型草原土壤有机碳含量均呈现出随着土壤深度增加而降低的变化趋势,但土壤全氮有明显的垂直空间异质性,草甸草原及盐生草甸土壤全氮含量随土层加深而降低,其余类型草原均以中间层含量最高,表层及深层土壤全氮含量较低;(3)锡林郭勒草原浅层土壤有机碳含量与土壤含水率、土壤容重及土壤孔隙度呈显著相关性,土壤全氮含量与土壤pH值及土壤含水率显著正相关(;4)锡林郭勒草原土壤有机碳含量受气候因素的影响较为显著,呈明显的相关性,土壤全氮含量受气候因素影响较小。

In order to clarify the spatial distribution characteristics of soil carbon and nitrogen in Xilingol Steppe and the mechanism of environmental impact,this study took the grassland soils in different habitats of Xilingol as the research objects,analyzed the spatial differentiation law of soil carbon and nitrogen content,and explored the change trend of grassland environmental climate factors and the driving relationship of soil carbon and nitrogen dynamics.The results showed that:(1)In Xilingol Steppe,the average content of organic carbon was 1.46%,with meadow steppe>typical steppe>salt meadow>typical steppe in sandy land>desert steppe;the average content of total nitrogen was 0.26%,with meadow steppe>typical steppe>typical steppe in sandy land>desert steppe>salt meadow.(2)The soil organic carbon content in different steppe types showed a trend of decreasing with the increase of soil depth,but there was obvious vertical spatial heterogeneity for soil total nitrogen content.The soil total nitrogen content in meadow steppe and salt meadow decreased with the increase of soil depth,and the middle layer of other steppe types had the highest content,and the soil nitrogen content of surface and deep soil layer was lower.(3)In shallow soil of Xilingol Steppe,soil organic carbon content was significantly correlated with soil water content,bulk density and porosity,and soil total nitrogen content was significantly positively related to soil pH value and soil water content.(4)Soil organic carbon content was significantly affected by climate factors with an obvious correlation,while soil total nitrogen content was less affected by climate factors.