Rhizosphere microbial stability and phosphorus availability drive garlic growth differences

Background The rhizosphere microbiome and soil nutrients are critical for crop growth, but their roles in regulating garlic productivity remain unclear. This study aimed to identify key factors driving growth differences in adjacent garlic fields with uniform management. Methods Rhizosphere soils from two adjacent plots (H: vigorous growth; L: stunted growth) were analyzed for physicochemical properties and microbial communities via 16S rRNA and ITS sequencing, combined with network analysis and redundancy analysis (RDA). Results Results showed significantly higher available phosphorus (AP) in H than L. Bacterial communities in H exhibited greater stability and core diversity, with distinct compositional clustering between sites (PERMANOVA, P < 0.001). RDA indicated AP strongly correlated with bacterial community structure (R²=0.7638, P=0.009), and H was enriched with phosphorus-transforming taxa (e.g., Arthrobacter, Thauera). Hierarchical partitioning highlighted bacterial communities as the primary driver of growth differences, followed by AP. Conclusions These findings reveal that AP availability and rhizosphere bacterial stability, mediated by phosphorus-transforming microbes, collectively shape garlic growth, providing insights for optimizing garlic cultivation through microbial management.