影响呼伦贝尔草原土壤有机碳空间变异的主导因素OA北大核心CSTPCD

[Background]Soil organic carbon(SOC)is a key component of the global carbon cycle in grassland ecosystems.In the context of climate change and grassland soil degradation,the study of the grassland carbon cycle has garnered extensive attention,particularly the in-depth analysis of the dynamics and driving factors of soil organic carbon in grasslands at different temporal and spatial scales.However,the estimation of long-term dynamic changes and the analysis of drivers for spatial variation in grassland SOC are primarily based on remote sensing modeling methods and simulation predictions,rather than direct measurements.[Objective]The aim of this study was to evaluate the relative importance of SOC spatial variation factors and their variation characteristics in different periods of Hulunbuir grassland.[Method]Based on the data of the second national soil survey in the 1980,the soil profiles of 31 sample sites in Hulunbuir grassland in 2022 were collected again,and the SOC changes and driving factors of Hulunbuir grassland were quantitatively analyzed in these two periods by establishing a multivariate linear model and a generalized additive model.[Result]From 1980 to 2022,the SOC of Hulunbuir grassland increased from 17.25 g·kg-1 to 17.62 g·kg-1 in 40 years,with an increase of 0.37 g·kg-1.The relative importance of climatic factors increased from 22.1％in the 1980 to 72.9％in 2022,compared with a decrease in the relative importance of the topography and utilization intensity factors,which decreased from 38.8％and 39.2％in the 1980 to 13.5％and 13.5％in 2022,respectively.[Conclusion]The climatic factors,topography and use intensity jointly dominated the spatial variation of soil organic carbon in Hulunbuir grassland.Over the past 40 years,the climate factors have evolved from a secondary contributor to grassland SOC change to a major controlling factor.