Effects of different plant-derived fermentation products as soil amendments on microbial community structure and mitigation of soil degradation caused by replanting

Soil amendments play a pivotal role in revitalizing soil ecosystems degraded by continuous intensive farming practices. However, existing research primarily focuses on chemical or biological amendments, overlooking the potential of plant-derived fermentation products. The influence of plant fermentation products on diverse soil functions and their underlying connections with soil microbial communities remains elusive. This study delves into the effects of various plant fermentation products as innovative amendments on transplanted soil. We evaluated soil functions encompassing ginseng yield and quality, nutrient cycling processes, soil enzymatic activities crucial for primary production, and physicochemical properties. Our findings reveal that plant fermentation products effectively enhance soil functions, with XS (fine Manchurian wildginger and Shiso) exhibiting the most pronounced impact on restoring soil fertility compared to untreated aged ginseng soil. Furthermore, application of these products altered bacterial and fungal community compositions, marked by increased relative abundances of dominant bacterial phyla (e.g., Actinobacteria and Proteobacteria) and fungal phyla (e.g., Ascomycota and Basidiomycota). Notably, bacterial networks exhibited greater complexity post-treatment, suggesting a more responsive nature to environmental changes compared to fungi. Bacterial networks were dominated by positive interactions, significantly stronger than those in fungal networks. Functional predictions indicate that treatments involving plant fermentation products modified the metabolic capabilities of soil fungal communities. Additionally, these treatments significantly reduced plant disease incidence associated with transplantation, with XS being the most effective. In conclusion, our results demonstrate that plant fermentation products foster stronger intra- and inter-microbial interactions, thereby enhancing soil ecosystem multifunctionality and promoting sustainable agriculture.