Comparative Analysis of Effects of Nutrient Management Practices on Soil Microbiome and Rhizosphere Chemistry in Brinjal (Solanum melongena L.)

Brinjal (Solanum melongena) is one of the most tropical vegetable crops cultivated worldwide. Rhizosphere microbial dynamics play a crucial role in plant nutrition, providing valuable insights into soil fertility and sustainable agricultural practices. This study aims to identify sustainable nutrient management practices for brinjal, focusing on the rhizosphere microbiome by examining various nutrient management approaches, including integrated nutrient management (INM), inorganic fertilization, and organic fertilization. Root architectural analysis, LC-MS-based metabolite profiling, and shotgun metagenomics were employed to assess the various nutrient management-induced changes in metabolites and the microbial community. The result suggested that superior root features, including volume (16.3 cm3), surface area (399.48 cm2), and total root length (794.89 cm), were achieved under INM. Additionally, it encompassed the highest number and diversity of root metabolites, including both primary and secondary compounds. This can be the reason for INM maintaining a balance between the representation of bacteria (87.4%) and fungi (12.4%), with Actinomycota and Ascomycota being the dominant groups. Further diversity analyses revealed that INM soils supported the highest microbial richness and OTU abundance, while inorganic fertilization favored greater evenness of taxa but lower richness. Organic soils harbored unique, less abundant taxa, reflected in higher Fisher’s alpha values. The beta diversity analysis indicated distinct microbial community structures across different treatments. Therefore, INM is a sustainable solution for brinjal cultivation, since it improves crop performance, soil health, and microbial ecosystem services.