Response of Soil Carbon Mineralization to Grassland Management Practices on the Qinghai‐Tibetan Plateau

Abstract Grassland management practices strongly influence soil carbon dynamics, yet their effects on carbon mineralization processes in high‐altitude regions remain poorly understood. We examined soil carbon mineralization patterns under four common grassland management practices implemented on the Qinghai‐Tibetan Plateau (i.e., seasonal grazing, continuous grazing, perennial artificial grasslands, and annual artificial grasslands) using a 147‐day incubation experiment. We also analyzed soil properties, microbial communities, and carbon degradation genes to understand the mechanisms driving carbon mineralization. We observed distinct depth‐dependent responses to management practices. In surface soils (0–0.15 m), seasonal grazing exhibited the highest cumulative carbon mineralization (2993.32 mg CO 2 ‐C kg −1 ), 1.5‐fold higher than annual artificial grasslands. However, in subsurface soils (0.15–0.30 m), continuous grazing showed the greatest cumulative carbon mineralization (2355.18 mg CO 2 ‐C kg −1 ), 1.5‐fold higher than perennial artificial grasslands. Collectively, soil properties, carbon degradation genes, and fungal diversity explained 74% of the variation in cumulative carbon mineralization, with soil properties showing the strongest direct effect (path coefficient = 0.62). Interestingly, bacterial diversity exhibited a negative relationship with cumulative carbon mineralization, suggesting previously underappreciated mechanisms of carbon preservation involving microbial‐derived compounds and their interaction with soil minerals. The variability in the abundance of specific carbon degradation genes across grassland management practices revealed that peroxidase and limonene 1,2‐epoxide hydrolase genes showed positive correlations with cumulative carbon mineralization. Our results suggest that optimal soil carbon management in high‐altitude grasslands is challenging and requires careful consideration of both grassland management practices and soil depth, especially spatial and temporal patterns of grazing pressure.