Manure Application Affects Soil Bacterial Community Structure in the Maize-wheat Rotation System of North China Plain

A 2-year maize-wheat rotation experiment was conducted to clarify the characteristics of soil bacterial community under reduced fertiliser-N application rate on the North China Plain. Treatments were conventional fertilisation (CF), 80% fertiliser-N input (80%N) and 80% fertiliser-N plus manure input (80%NM) in the wheat season, while the fertilisation regimes of previous maize were consistent. Results showed that 80%NM increased wheat ear·m-2 and 1,000-grain weight by 5.1% and 7.5%, and it also increased soil C/N ratio (by 29.1%) and dissolved organic N content (by 41.6%), compared with CF, although the difference in crop yields between treatments was not significant. Values of soil bacterial α-diversity parameters (observed species, chao1 estimator, evenness and Shannon’s diversity index) were improved under 80%NM, but not under 80%N. Compared with CF, 80%NM increased the abundance of phyla Firmicutes and Gemmatimonadetes but decreased the abundance of phylum Acidobacteria. Redundancy analysis indicated that organic C, dissolved organic N and C/N ratio were major environment variables affecting the distribution of bacterial phyla. These results suggest that manure application can improve soil fertility and productivity under reduced fertiliser-N application rate.