Beyond Conventional Fertilization: Integrating Soil Stoichiometry, Microbiomes and Crop Demand for Sustainable Nutrient Management

Abstract

Synthetic fertilisers have supported modern crop production, but nutrient use efficiency remains constrained by losses, nutrient imbalances and the biological processes that regulate nutrient availability. This review examines sustainable nutrient management by integrating three complementary perspectives: soil ecological stoichiometry, soil and rhizosphere microbiomes, and dynamic crop nutrient demand. It synthesises evidence showing that carbon, nitrogen and phosphorus ratios influence microbial growth, nutrient immobilisation and mineralisation, while microbial communities regulate nitrogen transformations, phosphorus mobilisation and root access to nutrients. Crop nutrient requirements are shown to vary with genotype, phenological stage and root acquisition traits, making temporal and spatial synchrony between nutrient supply and crop demand essential. The review also evaluates microbial inoculants, organic amendments and precision nutrient-management approaches, emphasising that their effectiveness depends strongly on soil conditions, resource balance and biological context. An integrated diagnose–amplify–deliver framework is presented in which soil and microbial diagnostics guide the strengthening of biological nutrient supply and the targeted delivery of mineral nutrients according to crop demand. The synthesis indicates that this approach could improve nutrient use efficiency while reducing unnecessary nutrient surpluses, although its practical application requires locally calibrated indicators, field validation, reliable microbiome interventions and accessible decision-support tools. The framework also recognises contrasting regional priorities, from reducing excessive nutrient inputs to rebuilding fertility in nutrient-depleted systems.