Integrated Nutrient Management (INM) practices that combine organic manures, biofertilizers, and reduced chemical inputs significantly enhance soil microbial diversity and nutrient availability over multiple cropping seasons. This integrated approach improves the biological, chemical, and physical properties of soil, promoting a healthy and diverse microbial community in the rhizosphere. The organic matter from manures and compost serves as an energy source for microbes, while biofertilizers (beneficial microorganisms) aid in processes like nitrogen fixation and phosphate solubilization, further enriching microbial activity.

The application of organic amendments provides readily available carbon sources that stimulate the growth and metabolic activity of beneficial soil microorganisms. These microbes play key roles in the decomposition of organic matter, mineralization of nutrients, and formation of stable humus, which improves long-term nutrient cycling. INM promotes a diverse microbial community, including nitrogen-fixing bacteria, phosphate-solubilizing microbes, and decomposers, thereby enriching the soil microbiome. The inclusion of biofertilizers (such as Azotobacter, Rhizobium, Azospirillum, Pseudomonas, and Trichoderma) further enhances microbial-mediated nutrient mobilization. These microbes improve nutrient solubility, increase nutrient uptake efficiency, and help in maintaining microbial equilibrium, particularly in the rhizosphere. Over multiple cropping cycles, INM leads to an accumulation of organic matter, which not only improves microbial habitats but also stabilizes microbial functional diversity. This results in sustained microbial-driven processes like nitrogen fixation, phosphorus solubilization, and micronutrient transformation, ultimately improving nutrient availability without environmental degradation.

Over successive seasons, INM improves soil organic carbon, cation exchange capacity, moisture retention, and nutrient cycling efficiency, resulting in more sustained and balanced nutrient availability. Additionally, these practices reduce dependency on synthetic fertilizers, minimizing soil degradation and nutrient leaching. In contrast, continuous use of chemical fertilizers alone can reduce microbial biomass and limit microbial diversity, particularly through soil acidification and lack of organic substrates. INM, therefore, represents a microbially favorable nutrient strategy that aligns soil biological health with sustainable crop production