Home-field advantage in soil respiration and its resilience to drying and rewetting cycles

Climate change is expected to increase extreme weather events, such as more extreme drought and rainfall incidences, with consequences for ecosystem carbon (C) cycling. An understanding of how drying and rewetting (DRW) events affect microbe-mediated soil processes is therefore critical to the predictions of future climate. Here, a reciprocal-transplant experiment was conducted using two soils originated from distinct climate and agricultural managements to evaluate how soil biotic and abiotic properties regulate soil respiration and its resilience to simulated DRW cycles. We found that regardless of the DRW intensity, the effects of microbial community on soil respiration and its resilience to DRW cycles were dependent on soil type. Soil microbial communities yielded higher respiration rates and resilience in native than foreign soils under both one and four DRW cycles, supporting the "home-field advantage" hypothesis. Structural equation modeling demonstrated that soil pH and total C directly influenced soil respiration, but effects of soil abiotic properties on respiration resilience were mediated by microbial communities. Among microbial drivers, the microbial C utilization capacity (as characterized by community-level physiological profile, C-acquisition enzyme activities and microbial metabolic quotients) was the best predictor of respiration resilience to DRW cycles, followed by microbial biomass carbon/nitrogen ratio and microbial community composition. Our study suggests that soil microbial communities may have adapted to their historical conditions, which facilitates the resilience of soil respiration to changing environments, but this adaptation may accelerate C loss from soils facing increasingly variable climate.