Soil organic matter contents modulate the effects of bacterial diversity on the carbon cycling processes

Purpose Bacterial diversity drives multifunctionality in ecosystems, including carbon cycling, while a comprehensive understanding of how carbon contents modulate microbial function through bacterial diversity is unknown. The exact extent of the contribution of organic matters contents to carbon cyling process will be investigated using a dilution-to-extinction methods in soils. Materials and methods We conducted a dilution-to-extinction experiment to manipulate the bacterial diversity in soils amended with five different organic matter contents. Meanwhile, the abundance and community structure of bacteria were detected by quantitative PCR and high-throughput sequencing, respectively. Furthermore, the dehydrogenase activity, cellulase enzyme activity and β-glucosidase enzyme activity were detected. Results and discussion The co-occurrence patterns of sensitive bacterial communities in the soil with 5 organic matter contents showed that organic matter content had a strong effect on sensitive bacterial network complexity. The degree of functional redundancy varied with soil organic matter contents, which was attributed to the interactions among organisms. Conclusions Soil carbon contents exerted a strong influence on ecosystem function, and bacterial diversity plays a predominant role in soil with low organic content. Our findings showed the contribution of bacterial diversity in modulating soil function and shed new light on the role of microbial groups in land restoration.