Geographical variations in soil properties and bacterial community diversity across major lavender (Lavandula angustifolia Mill.) cultivation regions in the Ili River Valley

The Ili region hosts China's largest lavender cultivation base, yet soil bacterial diversity in its primary cultivation areas remains understudied. To address this, we compared soil bacterial communities across four major cultivation counties (Chabuchar, Agricultural Research Institute, Yining, and Huocheng). Essential oil profiles, soil properties, and bacterial community characteristics were analysed to elucidate microbial variations and environmental interactions. The results showed that: (1) The essential oil yield (1.14%) and linalool content (41.04%) in the Huocheng County cultivation area were significantly higher than those in other areas, and the essential oil quality was relatively the best; (2) the soil bacterial communities in different main cultivation areas shared certain commonalities. At the phylum level, Proteobacteria, Acidobacteriota, Gemmatimonadota, and Actinobacteriota were the dominant phyla, and their relative abundances varied by region and soil layer, and (3) the redundancy analysis results showed that soil bacterial communities were comprehensively affected by environmental factors such as pH, total nitrogen, total phosphorus, soil organic carbon, longitude, and altitude. The significant positive correlations between the abundance of Vicinamibacteraceae (Acidobacteriota) in Huocheng County soils and both soil total phosphorus and linalool content suggest a putative mechanism whereby this bacterial taxon enhances lavender terpenoid synthesis by facilitating phosphorus cycling. Overall, these results suggest that geographically driven climatic variations dynamically alter the soil bacterial community, thereby influencing lavender growth and the final essential oil quality.