Application of organic fertilizer improves microbial community diversity and alters microbial network structure in tea (Camellia sinensis) plantation soils

Abstract Soil microbiomes contribute to plant growth, health and agricultural production. However, the influence of long-term application of different fertilizers on soil microbial diversity and community structure of tea (Camellia sinensis) plantations remains unclear. Here it was hypothesized that organic fertilizer treatment (OF) would significantly improve the microbial diversity and alter the microbial community structure, leading to the support of more soil ecosystem functions in tea plantation. To test this, we investigated microbial communities of tea plantation soils under different long-term fertilization treatments using both high-throughput 16S rRNA gene Illumina sequencing and molecular ecological network analysis. Soil samples (Red soils, classified as Haplic Acrisol) were collected from 5 large experimental tea plantations under different long-term fertilization treatments (organic fertilizer (OF), chemical fertilizer (CF) and non-fertilizer (NF)) in central south of China in August 2017. Soils under OF treatment had higher microbial diversity compared with soils under other treatment regimes. Unweighted principal coordinate analysis (PCoA) results revealed a clear separation among the groups of tea plantation soils under the three treatment regimes. Relationship analysis between soil properties and microbial communities showed that pH and nitrate nitrogen (NO3-N) concentration were key physicochemical factors that significantly influenced microbial diversity and community structure. Furthermore, network analysis indicated that the network of OF treatment soils contained more functionally interrelated microbial modules than soils with CF treatment and that the topological roles of characteristic microorganisms and key microbial organisms were significantly different between CF and OF treatments. Relative to CF treatment, the relative abundances of organisms belonging to chemoheterotrophy, fermentation, nitrogen fixation, and aerobic nitrite oxidation functional groups in tea plantation soils under OF treatment were significantly increased by 28.74%, 110.10%, 41.16% and 556.64%, respectively (p