Sustainable phosphorus delivery using advanced slow-release fertilizers: A review

Phosphorus, an indispensable macronutrient, is crucial for global agricultural productivity; however, its inefficient use and environmental losses are critical drawbacks. The current review comprehensively explores the chemistry, transformations, and dynamics of P in soil, and clarifies how P stratification, pH, and interactions with organic matter affect P's bioavailability. The changing field of P-based slow-release fertilizer research is systematically mapped using timeline analysis and keyword co-occurrence network analysis to identify key knowledge clusters and new avenues for investigation. The review critically assesses the agronomic performance and ecological effects of P fertilizers by further classifying them into water-soluble, citrate-soluble, and citrate-insoluble forms. Furthermore, the mechanism-based classification of slow-release fertilizers is discussed in comprehensive detail. The constraints imposed by inefficient P use and the resulting need for sophisticated fertilizer technologies are given particular attention. Recent nanotechnological developments in layered double hydroxides, graphene oxides, nanohydroxyapatite, polymeric nanomaterials, and nanoclays are examined as promising approaches to increase P availability while reducing environmental hazards. The review also covers sequential extraction techniques for measuring soil P fractions, providing insights into interactions between fertilizer and soil. All things considered, this paper emphasizes the critical need for a paradigm change towards slow-release, precision-engineered P fertilizers that balance environmental stewardship with agricultural productivity.