Professor Northeast Forestry University, China (People's Republic)
Drought events occur more frequently under the context of global change, with dramatic impacts on soil carbon (C) dynamics. Although numerous studies have investigated drought-induced changes in soil C decomposition, how plant-microbial interaction regulate responses of decomposition to drought remains unclear. We conducted a 9-year field experiment (2014 - 2022) of rainfall exclusion nested with root trenched treatments in a subtropical forest to examine the interaction of plant roots and microorganism on soil C decomposition under drought. Drought and root growth decreased soil C decomposition by 18.42% and 7.43%, respectively, with stronger root effect in ambient vs. drought environment. These changes in C decomposition were mediated by soil fungi and enzyme activity. Drought decreased soil C, nitrogen and phosphorus-degrading enzyme activity and bacterial diversity, but increase saprotrophic fungal diversity. Root growth increased enzyme activity and bacterial diversity. Variance partition analysis showed that microbial biodiversity explained more of the drought-induced variation in decomposition than did other variables. This study highlights the importance of microbial biodiversity in regulating the response of C decomposition to drought. Incorporating these evidences into into earth system models might improve model performance and projection of long-term soil C dynamics.
