Interaction of Silicon Fertilizer, Soil, and Chinese Cabbage: Quality Enhancement and Rhizosphere Microbiome Remodeling

Background and Aims Chinese cabbage (Brassica rapa ssp. pekinensis) is a crucial leafy vegetable crop in China and globally. It ranks first in terms of planting area and output among all vegetables and is an important economic and livelihood-supporting crop. Methods This study investigated the effects of five concentrations (15, 24, 36, 60, and 72 L/hectare) of a Si-containing water-soluble fertilizer applied via root irrigation on cabbage cultivar 'Jingcui 60' under greenhouse conditions. Reselts Results showed that moderate Si application (T3 and T4) significantly promoted plant growth, with T3 increasing shoot fresh weight by 47.8%. Si fertilization also enhanced cabbage quality, with T4 increasing leaf amino acid content by 99% and T2 boosting soluble sugar content by 42.25%. Soil analysis revealed that Si increased soil EC, organic matter, and alkali-hydrolyzable nitrogen and enhancing soil enzyme activities. Microbial profiling showed that Si reshaped bacterial and fungal communities, in creasing bacterial richness, promoting beneficial genera like Bacillus, and suppressing pathogenic fungi such as Fusarium. Conclutions The 60 L/hectare application rate (T4) provided the most benefits. This study clarifies the soil-microbe-plant interactions in Si-mediated quality regulation and provides a basis for precise Si fertilizer application in sustainable leafy vegetable production.