Soil Microbial Community Composition and Diversity Response to Varying Farmland Types

ABSTRACT Elucidating soil microbial community responses to different farmland types in metropolitan suburbs is vital for optimizing crop production management and preserving soil health. This study investigated four farmland types: dryland (DL), irrigated land (IL), paddy land (PL), and orchard (OL). Through high‐throughput sequencing and statistical methods including one‐way ANOVA and multiple comparisons, we compared soil physicochemical properties with microbial community structure and diversity. In OL, available phosphorus (AP) and total potassium (TK) contents were significantly higher than in other types. In IL, total nitrogen (TN) and total phosphorus (TP) were significantly elevated, whereas PL soils exhibited a significantly lower pH. PL harbored the highest number of unique bacterial and fungal operational taxonomic units. Proteobacteria dominated across all sites, with Bacteroidetes particularly abundant in PL and DL, and Firmicutes and Actinobacteria enriched in IL and OL. Clustering analysis of dominant genera revealed that DL, OL, and IL communities clustered together, distinct from PL. Bacterial richness (observed species) and diversity (Shannon index) were highest in PL and OL; fungal richness peaked in OL, while fungal diversity was greatest in IL. Redundancy analysis and Spearman's rank correlation analysis showed that TK, pH, TP, and available potassium (AK) were primary drivers of microbial community shifts; dominant genera and their diversity correlated with bulk density (BD), pH, AK, and TK. These results demonstrate marked differences in microbial community structure, diversity patterns, and physicochemical properties among metropolitan suburban farmland types, reflecting distinct microbial responses to farmland types.