FIGURE 2.

The main zones in soil, the characteristics that regulate microbial functioning within each zone, and the dominant guilds of microbes present. In litter and the rhizosphere (outlined in green), microbial community composition likely affects both the rate of processes and the fate of C. In mineral soil (outlined in brown), microbial community composition likely only controls the fate of C. In dead roots, community composition probably regulates both rate and fate, but little research has been done on this compartment.