Soil is the largest reservoir of terrestrial carbon (C) containing twice as much as the atmosphere and three times that in global vegetation. Enhancing the potential of agricultural soils to sequester C has implications for decreasing atmospheric CO2. Within soil, organic matter (OM) represents a significant pool of C. The decomposition of soil OM and breakdown of plant residues can be linked to C sequestration in agricultural soils as a portion of the decomposed C becomes assimilated into the microbial biomass and thus forms part of the stable OM pool. Microbial decomposition of this OM varies with OM quality, inherent soil properties, for example pH, and resident microbial communities and their functions. While the role of bacteria and fungi in OM decomposition has been the subject of numerous studies, the dynamics and functioning of the microorganisms involved remain under explored. In particular the succession and co-occurrence patterns of soil microbial communities during decomposition are poorly understood. Here we investigated, over the course of a 6 month incubation experiment, the influence of soil pH and plant residue quality on the dynamics and successional patterns of the microbial decomposer communities and subsequent impact on soil C. We utilised a barcoded sequencing approach and network analysis of bacterial 16S rRNA and fungal ITS to determine the key microbial groups involved in residue decomposition. As soil microbial communities mediate OM decomposition through the actions of their enzymes we also assessed OM and plant residue decomposition processes by determining the abundance of some of the genes associated with this process, for example laccases involved in lignin decomposition and cellobiohydrolases involved in cellulose decomposition.