In order to study the effects of different fertilization methods on the microbial community structure and diversity of tobacco planting soils under continuous cropping conditions, Illumina Miseq high-throughput sequencing technology was used and Metagenomics analysis was conducted to analyse the soil microbial communities under different fertilizer treatments. The control was inorganic compound fertilizer for tobacco: the application amount was 600 kg/ha, and N:P₂O₅:K₂O = 10:10:24. Based on the same rates as for the inorganic fertilizer, microbial fertilizers from different sources were added as other treatments. Xiangyun Guansheng organic fertilizer containing Bacillus amyloliquefaciens with an effective viable bacteria count of 0.02 B/g was used at a rate of 750 kg/ha. Midu Guofa Organic Fertilizer, whose main component is animal and plant compost, was also used. Fujian Sanju Solid Bacterium Fertilizer which contains Bacillus amyloliquefaciens, Arthrobacter tabacum and Bacillus jelly, with an effective viable bacteria count of 0.02 B/g, was used at a rate of 750 kg/ha; Fujian Sanju liquid bacteria fertilizer containing Bacillus mucilaginosus was used at a rate of 15 000 ml/ha.

Results showed that: (1) The amount of valid sequence data obtained after sequencing allegations was distributed between 37 417 - 390 002.75 reads, the average length was distributed between 259.8 - 271.7625 bp, and the number of operation classification units (OTUs) in each sample were distributed between 455.75 - 642.25. (2) The Wayne diagram showed that a total of 2143 OTUs were obtained, with a total of 88 OTUs. (3) Alpha diversity analysis showed that the richness of the microbial community in the soil treated with microbial fertilizer gradually increased according to the ACE index and Chao index, while no obvious changes were observed in the other treatments. This increase in the microbial community and diversity is more obvious according to the Shannon index and Simpson index. The diversity of microbial species in all the soil samples was increased. (4) Community structure analysis showed that the soil bacteria types in the sampled soil were categorized into 16 phyla, 44 classes, 45 orders, 45 families, 45 genera, and Ascomycota, Basidiomycota, and Zygomycota were in higher abundance. (5) The colony heat map showed that all the organic fertilization treatments increased the bacterial community composition in the soil compared with the control in which inorganic fertilizer was applied. The treated samples also had more bacterial diversity than that in the control. Conclusion: The bacterial structures of organic fertilizer groups were more closely aggregated than those of the inorganic fertilizer group, which indicated that the addition of microbial organic fertilizers could significantly change the bacterial structure of the soil in the case continuous tobacco cropping.