Agricultural Impacts on Soil Particulate Organic Carbon: The Role of Edaphic Factors in Global Tillage and Fertilization Responses

ABSTRACT Particulate organic carbon (POC) is a key indicator of soil health and plays a critical role in ecosystem functioning and land productivity. Its dynamics are strongly influenced by environmental disturbances and anthropogenic land‐use practices. However, the mechanisms by which agricultural practices regulate POC remain insufficiently understood. In this study, we synthesized 1179 paired observations from global agricultural landscapes to examine how common agricultural practices, tillage and fertilization, alter POC concentration and to identify the underlying mechanism modulated by edaphic and environmental factors. We found that tillage disrupts soil structure, alters bulk density and pH, and accelerates carbon decomposition, resulting in POC losses. In contrast, fertilization, particularly with organic amendments, enhances POC by promoting carbon inputs and supporting microbial turnover. Random forest model indicates that edaphic characteristics are the primary regulators of POC responses, while structural equation modeling demonstrates that total soil carbon mediates the effects of management practices on POC concentration. Overall, soil‐specific properties constrain plant inputs, physical protection, and microbial turnover, fundamentally determining POC responses to agricultural practices. These findings highlight the importance of targeted land management strategies to mitigate degradation and promote ecological restoration.