Microbial communities play a crucial role in soil carbon cycling, influencing processes such as decomposition and organic matter turnover. While some microbial processes, like trace gas emissions and nitrification, are sensitive to community composition, the broader processes of decomposition and organic matter turnover are less so. The paper discusses how microbial community structure influences carbon cycling, emphasizing the importance of phylogenetic levels in defining functional groups. It argues that microbial community composition is more influential in the rhizosphere and detritus than in mineral soil, where physical access to substrates is the rate-limiting factor. Microbial allocation of carbon, such as through extracellular enzymes and polysaccharides, can significantly affect soil structure and function. The study highlights the need for further research on microbial community dynamics in different soil compartments, particularly in dead roots, which may be a major source of soil carbon. The paper also discusses the importance of microbial life history strategies and the role of physical and chemical factors in regulating microbial community composition and function. Overall, the study emphasizes the complex interactions between microbial communities and soil carbon cycling, and the need for continued research to better understand these processes.Microbial communities play a crucial role in soil carbon cycling, influencing processes such as decomposition and organic matter turnover. While some microbial processes, like trace gas emissions and nitrification, are sensitive to community composition, the broader processes of decomposition and organic matter turnover are less so. The paper discusses how microbial community structure influences carbon cycling, emphasizing the importance of phylogenetic levels in defining functional groups. It argues that microbial community composition is more influential in the rhizosphere and detritus than in mineral soil, where physical access to substrates is the rate-limiting factor. Microbial allocation of carbon, such as through extracellular enzymes and polysaccharides, can significantly affect soil structure and function. The study highlights the need for further research on microbial community dynamics in different soil compartments, particularly in dead roots, which may be a major source of soil carbon. The paper also discusses the importance of microbial life history strategies and the role of physical and chemical factors in regulating microbial community composition and function. Overall, the study emphasizes the complex interactions between microbial communities and soil carbon cycling, and the need for continued research to better understand these processes.