Effects of microbial diversity loss on the stability of CO2 production and N2O emission in agricultural soils.

ABSTRACT

The relationship between biodiversity and ecosystem stability is a hot topic in ecology. However, current studies focus mainly on aboveground system with plants, little attention has been paid to belowground system with soils. In this study, we constructed three soil suspensions with varying microbial diversity (100, 10-2, 10-6) by the dilution method and inoculated separately into agricultural Mollisols and Oxisols to examine the stability (indicated by resistance and resilience) of soil CO2 production and N2O emission to copper pollution and heat stress. Results showed that the stability of CO2 production in Mollisols was not influenced by microbial diversity loss, while the resistance and resilience of N2O emission in Mollisols were significantly decreased at the 10-6 diversity. In the Oxisols, the resistance and resilience of N2O emission to copper pollution and heat stress started to decrease even at the 10-2 diversity, and the stability of CO2 production decreased at the 10-6 diversity. These results suggested that both soil types and the identity of soil functions influenced the relationship between microbial diversity and the stability of function. It was concluded that soils with ample nutrients and resistant microbial communities tend to have higher functional stability, and that the fundamental soil functions (e.g., CO2 production) are more resistant and resilient than the specific soil functions (e.g., N2O emission) in response to environmental stress.