Responses of cut-lily quality and rhizosphere soil microecology to different microbial inoculants

Continuous cropping obstacles and soil-borne diseases have long constrained the development of the cut lily industry, and microbial inoculants have become an important tool for achieving green production. To screen for efficient inoculants suitable for cut lily and to reveal the mechanisms of action, this study used the dominant cultivar 'Siberia' (Lilium 'Siberia') as material and conducted a field experiment under solar greenhouse conditions in Lingyuan, Liaoning Province, using three commercial microbial inoculants: Treatment A (Shentai Trichoderma combination, containing Trichoderma harzianum and its metabolites), Treatment B (Moon composite inoculant, containing Trichoderma, Purpureocillium lilacinum, Bacillus subtilis, etc.), and Treatment C (Fengde composite inoculant, mainly Bacillus subtilis). The study systematically measured lily growth and commercial traits, soil physicochemical properties, and rhizosphere microbial community structure, and analyzed the linkage mechanism of "inoculant-soil physicochemical properties-rhizosphere microbial community-comprehensive lily quality." The results showed that Treatment A (Shentai Trichoderma combination) had the best comprehensive effect, significantly increasing plant height, stem diameter, and green leaf rate, and reducing leaf yellowing and abscission index. At the same time, it significantly increased soil total nitrogen, total phosphorus, available nitrogen, and organic matter content, and optimized the rhizosphere microecological environment. Further microbial community analysis indicated that Treatment A specifically enriched putatively beneficial taxa such as Pseudomonas and Streptomyces, and functional fungi such as Trichoderma and Mucor, while reducing the relative abundance of potentially pathogenic taxa such as Fusarium and Rhizoctonia. It also increased the modularity and proportion of positive correlations in the bacterial-fungal co-occurrence network, forming a stable growth-promoting and disease-resistant functional module. This study clarifies the core effects of the Trichoderma-based inoculant on lily growth, soil improvement, and rhizosphere microecological regulation, suggests a mechanism by which it synergistically improves cut lily quality and stress resistance through optimizing soil nutrients and reshaping microbial community structure, identifies a promising inoculant formulation with potential for green lily production, and provides a theoretical basis and technical support for the sustainable development of the cut lily industry.