Active restoration of degraded alpine grassland weakens mineral-associated soil organic carbon retention

Active restoration is predominant to reverse grassland degradation and soil organic carbon (SOC) loss. However, early studies focused on the bulk soil carbon (C) dynamics upon grassland degradation and restoration, with limited evidence involving SOC fractions. Here, we explored how the particulate and mineral-associated OC (POC and MAOC), metal-bound OC, soil aggregate-associated OC, SOC molecular structure, and microbial-derived OC respond to grassland degradation and restoration on the Tibetan Plateau, and also studied the effects of active restoration on SOC fractions across grassland ecosystems through a global-scale meta-analysis. We found that POC and soil aggregate-associated OC contents substantially decreased, while MAOC content remained stable after grassland degradation. In contrast, short-term active restoration induced significant decrease in MAOC and metal-bound OC due to lower soil pH, but POC content remained stable, indicating that grassland restoration resulted in a d..., , , # Active restoration of degraded alpine grassland weakens mineral-associated soil organic carbon retention

## Data files include:

**Supplementary_data_1.xlsx**: Experimental design parameters, edaphic properties, physico-chemical protection, and soil organic carbon (SOC) content (total and fractions) for paired grassland treatments (intact, degraded, restored) across three geographically distinct sites. All data were collected by the authors. Blank cells represent missing data.

| variables | units | description |
| :------------- | :-------------- | :----------------------------------------------------------------------- |
| Land type | categorical | the paired treatments (i.e., intact, degraded and restored grassland)  |
| Site | categorical | the paired treatments by three geographically spaced demonstration sites |
| Sampling | categorical | five replicates measured 30 m ...,