Abstract
Microbial communities and metabolic activities play key roles in carbon (C) turnover in terrestrial ecosystems, which are directly and indirectly affected by freeze-thaw cycles. However, the immediate and legacy effects of freeze-thaw periods on soil microbial community structure and C metabolic activity in agricultural ecosystems were still not fully understood. In this study, we evaluated the changes in soil microbial community structure and C metabolic activity during the freeze-thaw period and the growth season under the condition of warming and straw return. The results showed that the microbial biomass and the ratio of fungi to bacteria (F/B) were sensitive to freeze-thaw cycles and straw return. Both gradually decreased during the freeze-thaw period. The ratio of gram-positive to gram-negative bacteria (GP/GN) gradually increased during the freeze-thaw period. Then all these changes recovered during the growth season. Microorganisms have a certain self-regulating ability to deal with freeze-thaw stress. In contrast, microbial C use efficiency (CUE) did not significantly change during the freeze-thaw period, but increased during the growth season. Microbial CUE had no significant correlations with microbial biomass, the F/B, and the GP/GN, while it was negatively related with the ratio of dissoluble organic C to dissoluble total nitrogen (N) and the imbalance ratio between resources and microorganisms (C:N imbalance). These findings suggested that soil stoichiometric ratio played important role in regulating microbial CUE, instead of microbial community characteristics.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call