Changes in the biological “regulators” of organic carbon mineralization in silted soils of check dams as a result of wet‐dry cycles

Abstract

AbstractClimate change is increasing the frequency of prolonged droughts and extreme rainfall events, with implications for ecosystem carbon (C) cycling and efforts to mitigate climate change. Exploring how wet and dry cycling events affect microbially mediated soil organic carbon (SOC) mineralization processes is critical for achieving global C neutrality targets. This study examines how drought, water stress, and wet‐dry cycles influence microorganisms and the SOC mineralization process. We found that wet‐dry cycles initially excited mineralization of SOC, but that soil mineralization gradually decreased as wet‐dry cycling continued. At the same time, the utilization of C sources by different microbial communities tended to change, from primarily carbohydrate, amines and acids to a single acid, esters, or alcohols. The limiting factors for SOC mineralization also varied when soils were exposed to drought, water stress, and wet‐dry cycles, and we quantified the direct and interactive contributions of each factor to SOC mineralization. The direct effects of the factors under drought and water stress were 0.70 and 0.74, while the interaction of the elements was only 0.29 and 0.24. The direct effects of the factors were only 0.30 under wet‐dry cycling conditions. Based on the results of this study, we propose a pathway for soil biological regulation of SOC mineralization during drought, water stress and wet‐dry cycles, in order to further clarify the microbial regulation mechanism related to SOC mineralization.