Shrub encroachment increases mineral-associated organic carbon accumulation but exhibits low saturation in global grassland

This dataset is designed to investigate the mechanisms by which soil organic carbon (SOC) fractions (POC and MAOC) respond to environmental changes or management practices. Based on the research hypotheses that “POC is more sensitive to external disturbances than MAOC” and that “MAOC has carbon sequestration potential,” we conducted a systematic review of academic literature to extract sample sizes and standard deviations, and calculated the natural logarithm of the response ratio (lnRR$) as the core effect indicator. The dataset includes raw data (Data.xls), classification metadata (grouping.csv), and effect value files organized by category (SOC/POC/MAOC_lnRR.csv). The provided R scripts (meta_R code.R and MAOCsat_R code.R) document in detail the entire statistical process, from the construction of random-effects models to the analysis of carbon saturation potential. This dataset not only reveals differences in turnover among various carbon pools but also provides critical support for evaluating soil carbon sequestration potential and optimizing ecosystem carbon models. The provided code can be used to directly reproduce the analysis results or for further development.