Mechanisms controlling soil carbon turnover and their potential application for enhancing carbon sequestration
Two major mechanisms, (bio)chemical alteration and physicochemical protection, stabilize soil organic carbon (SOC) and thereby control soil carbon turnover. With (bio)chemical alteration, SOC is transformed by biotic and abiotic processes to chemical forms that are more resistant to decomposition and, in some cases, more easily retained by sorption to soil solids. With physicochemical protection, biochemical attack of SOC is inhibited by organomineral interactions at molecular to millimeter scales. Stabilization of otherwise decomposable SOM can occur via sorption to soil surfaces, complexation with soil minerals, occlusion within aggregates, and deposition in pores inaccessible to decomposers and extracellular enzymes. Soil structure (i.e.,more »