Carbon loss due to grassland reclamation in the agro-pastoral ecotone of northern China

The conversion of grasslands to cropland can significantly impact the terrestrial carbon cycle, yet the effects on soil organic carbon (SOC) are not well quantified due to a lack of large-scale sampling data. This study aims to quantify changes in SOC resulting from grassland reclamation in the agropastoral ecotone of northern China through paired sampling of 101 cropland plots and 101 adjacent grassland control plots. Results indicate that grassland reclamation led to an average 16.07% decrease in surface SOC content (0–10 cm). Over 80% of the study area experienced a loss in SOC, while less than 20% showed an increase. These findings underscore the significant impact of grassland reclamation on SOC depletion and highlight the importance of land management strategies to mitigate carbon loss in this region.