Vertical distribution of bacterial community in purple soil of winter-flooded paddy fields in different seasons

Abstract:

[Background] Soil bacteria are very sensitive to environmental changes and thus are important index of soil environmental quality. [Objective] To study the vertical distribution of soil bacteria in purple soil of winter-flooded paddy fields in different seasons and reveal the relationship between soil bacterial community structure, species diversity and soil environmental factors. [Methods] Purple soil of winter-flooded paddy fields were taken as the research object in this study. Soil samples at different depths were collected in August 2020 (summer) and January 2021 (winter) separately. Illumina MiSeq high-throughput sequencing of 16S rRNA gene of soil bacteria was performed to analyze the vertical distribution of bacterial community composition and diversity in different seasons. [Results] The bacterial ACE index, Chao1 index and Shannon index were higher in summer than in winter, and decreased with the increase of soil layers. The dominant bacterial phylum in purple soil of winter-flooded paddy fields were Proteobacteria, Chloroflexi, Acidobacteria, Nitrospirae, Actinobacteria and Planctomycetes, and the dominant bacterial genera were Desulfobacca, Haliangium, Anaeromyxobacter, Candidatus_Omnitrophus and Defluviicoccus. The relative abundances of Chloroflexi, Actinobacteria, Anaeromyxobacter and Candidatus_Omnitrophus were higher in summer, while those of Proteobacteria, Nitrospirae, Desulfobacca, Haliangium and Defluviicoccus were higher in winter. The redundancy analysis (RDA) and correlation analysis of environmental factors showed that total nitrogen (TN), soil organic matter (SOM) and soil redox potential (Eh) were the main factors that significantly affected the bacterial community structure in purple soil. [Conclusion] This study enriched the understanding of bacterial community composition and diversity in purple soil of winter-flooded paddy fields, and confirmed that there were differences in different seasons.