Abstract
Structural barriers and nutrient scarcity constrain medicinal plant cultivation in coastal saline soils. To address these challenges, we investigated a physical-chemical-microbial synergistic remediation strategy using Fenlong-ridging (FR) and a composite modifier (CM) by evaluating four soil treatments: conventional tillage; FR only; a CM only and FR combined with a CM (FR_CM). A comparative analysis of the four treatments revealed FR_CM to be the most influential strategy for improving coastal saline soil. The FR_CM treatment reduced soil electrical conductivity and bulk density by 78.38% and 29.31%, respectively; enhanced soil nutrient content and Isatis indigotica Fortune biomass by 68.91-114.29% and 126.52%, respectively; induced significant reorganization of microbial community structure at the phylum/OTU levels; elevated microbial network parameters, including positive/negative correlation ratios, modularity, and average path length; and enriched functional taxa such as fermentation and chitinolysis, while enhancing stress-tolerant phenotypes and suppressing potentially pathogenic phenotypes. This work establishes a theoretical foundation and technical paradigm for microbial-mediated remediation in saline-alkali ecosystems to assist crop-to-environment adaptation strategies and maintain sustainable medicinal plant production.