Characteristics of maize residue decomposition and succession in the bacterial community during decomposition in Northeast China

Microbes are decomposers of crop residues, and climatic factors and residue composition are known to influence microbial growth and community composition, which in turn regulate residue decomposition. However, the succession of the bacterial community during residue decomposition in Northeast China is not well understood. To clarify the property of bacterial community succession and the corresponding factors regulating this succession, bags containing maize residue were buried in soil in Northeast China in October, and then at different intervals over the next 2 years, samples were analyzed for residue mass and bacterial community composition. After residue burial in the soil, the cumulative residue mass loss rates were 18, 69, and 77% after 5, 12, and 24 months, respectively. The release of residue nitrogen, phosphorus, and carbon followed a similar pattern as mass loss, but 79% of residue potassium was released after only 1 month. The abundance, richness, and community diversity of bacteria in the residue increased rapidly and peaked after 9 or 20 months. Residue decomposition was mainly influenced by temperature and chemical composition in the early stage, and was influenced by chemical composition in the later stage. Phyla Actinobacteria, Bacteroidetes, and Firmicutes dominated the bacterial community composition in residue in the early stage, and the abundances of phyla Chloroflexi, Acidobacteria, and Saccharibacteria gradually increased in the later stage of decomposition. In conclusion, maize residue decomposition in soil was greatly influenced by temperature and residue composition in Northeast China, and the bacterial community shifted from dominance of copiotrophic populations in the early stage to an increase in oligotrophic populations in the later stage.