Pyrosequencing-based assessment of soil microbial community structure and analysis of soil properties with vegetable planted at different years under greenhouse conditions

Soil microbes play an important role in maintaining soil health, and identifying microbial changes in greenhouse soils is vital for improving soil quality. This study was aimed to investigate the changes in microbial diversity and soil characteristics at different cultivation years in greenhouse vegetable production at different sites. Soil DNA was extracted, and bacterial v4-v5 16S rRNA and fungal internal transcribed spacer gene region were pyrosequenced to analyze the microbial communities. Soil properties and enzymatic activities were determined. Soil pH decreased and showed strong linkage to microbial community compositions, whereas soil organic matter increased. Significant increases were observed not only in the total but also in the available nitrogen (N) (AN), phosphorus (P) (AP), and potassium (K) (p < 0.05). Proteobacteria, Firmicutes, and Bacteroidetes were significantly enriched (p < 0.05) under different cultivation years, whereas Chloroflexi and Acidobacteria were significantly decreased. The predominant fungal phylum was Ascomycota whereas Basidiomycota and Actinomycetes exhibited significant decreases (p < 0.05). AP was strongly linked to bacterial structure, whereas AN was strongly related to fungal distribution. Our results suggest that soil bacteria and fungi respond differently to cultivation years under greenhouse conditions. This study provides insights into the improvement of soil quality in protected agricultural production.