Soil pH modulates the global stabilized soil organic carbon

Soil mineral-associated organic carbon (MAOC) constitutes over 50% of total soil organic carbon (SOC) and serves as a key determinant of its long-term stabilization. Although soil pH is recognized as a "master variable" in biogeochemical cycles, it remains unclear how soil pH influences MAOC and SOC at large spatial scales. To address this knowledge gap, we conducted a continental-scale survey in China and synthesized global observations from literature, totaling 1300 independent observations. We analyzed the relationships between SOC and MAOC across pH gradients and assessed the contributions of other environmental factors to MAOC variability.