黄土区典型流域土壤有机碳-无机碳转化及驱动因素OA

The soil carbon pool in arid and semi-arid regions maintains dynamic balance to dominate the car-bon cycle through the sequestration and decomposition of soil organic carbon(SOC)and the precipitation and reformation of soil inorganic carbon(SIC).In nutrient-poor drylands,SIC constitutes the dominant fraction,yet the mechanisms underlying SOC-SIC transformation remain poorly understood.In this study,field sampling and carbon stable isotope analysis were conducted in the Manliangou watershed,Inner Mongolia,the transfor-mation mechanisms of soil organic-inorganic carbon and their driving factors have been revealed.Results show that artificial forests and grasslands significantly enhance SOC content,with the highest levels in the forest land,while SIC can be accumulated in deeper layers;bare gully slopes exhibit the highest surface SIC con-tent.Soil respiration on bare gully slopes releases the largest amount of CO2,leading to stronger SOC-SIC transformation than that in restored areas,although the overall transfer amount is relatively low(0.039 g/kg).Particulate organic carbon dominates SOC-SIC transformation in grasslands,while woodland is driven by soil moisture.