Abstract:

Agricultural carbon emissions account for about 25% of the annual global CO₂ emissions. To achieve the goal of carbon neutrality in China before 2060, the absorption and emissions of CO₂ in agriculture need to reach a dynamic balance. Soil organic carbon (SOC) mineralization is a biochemical process of microbial decomposition of SOC which provides nutrients for crop growth and releases greenhouse gases such as CO₂ to the environment. SOC mineralization in farmland is closely related to crop nutrient supply, carbon sequestration and CO₂ emission, but SOC mineralization is affected by many factors. Soil tillage is the key factor driving farmland soil carbon fixation, and the impact of tillage methods on SOC is an important part of agricultural ecosystem carbon cycle research. Soil aggregates with different particle sizes are regarded as biochemical reactors for microbial carbon mineralization to produce CO₂. The mineralization and decomposition of SOC can not be separated from the use of microorganisms and corresponding enzymes. Therefore, the tillage methods directly change the structure of soil aggregates, then change the microbial groups in soil, and ultimately affect SOC mineralization. This review summarized the effects of tillage methods, soil aggregates and associated soil microorganisms on SOC mineralization in farmland, aiming to reduce the occurrence of SOC mineralization in farmland, and provide theoretical support for China to achieve the goal of “double carbon” (peaking carbon emissions and achieving carbon neutrality).

Key words: organic carbon mineralization, soil tillage, soil organic carbon, aggregates, microorganisms