Integrated Nutrient Management for Sustained Soil Health and Rice Productivity: A Contemporary Review

Abstract

Rice systems must deliver high, stable yields while restoring soil function and lowering nutrient losses. Integrated nutrient management (INM) offers a practical pathway by coordinating organic resources, balanced mineral fertilization, biological inputs, and site-specific decision tools within water regimes typical of paddy agriculture. This review synthesizes recent field experiments, long-term trials, and global syntheses across irrigated and rainfed ecologies to evaluate how INM components—manures and composts, green manures and residue return, biochar and silicon sources, balanced N-P-K with secondary and micronutrients, enhanced-efficiency nitrogen products, deep placement and split timing, microbial inoculants, and digital/site-specific nutrient management—shape soil health and rice productivity. Evidence shows that partial substitution of mineral fertilizers with well-managed organic inputs, coupled with balanced macronutrients and critical micronutrients, enhances soil organic carbon, aggregation, microbial biomass, and enzyme activity while sustaining or modestly increasing yields. Enhanced-efficiency fertilizers and deep placement reduce volatilization, leaching, and nitrous oxide formation, particularly when synchronized with alternate wetting and drying at mild thresholds. Microbial products deliver context-dependent benefits that are most reliable when paired with organic substrates and moderate mineral doses; silicon nutrition strengthens stress tolerance and nutrient capture in constrained soils. Effective scaling depends on simple diagnostics, low-friction decision support, reliable input quality, and phased adoption that prioritizes nutrient balancing and water–nitrogen synchronization before layering additional practices. Priority research needs include defining optimal organic–mineral ratios by soil and climate, quantifying pool-specific carbon responses, standardizing inoculant quality, integrating water scheduling into nutrient advisories, and expanding large-N trials on micronutrients and silicon. Overall, INM enables rice systems to reconcile productivity, resilience, and environmental performance.