<p>Phosphate fixation in calcareous soils represents a major agronomic and environmental constraint because alkaline conditions and abundant CaCO₃ rapidly convert applied phosphorus into poorly available forms. Traditional phosphate fertilizers are often unsuitable, dissolving too quickly and forming insoluble calcium phosphates, thereby decoupling nutrient supply from plant demand. This review highlights recent advances in nanoclay-phosphate assemblies as next-generation fertilizers designed to overcome these limitations. We discuss the physicochemical mechanisms of phosphate adsorption, intercalation, and controlled-release from nanoclays, focusing on montmorillonite, layered double hydroxides, and related aluminosilicates. The integration of computational tools, including molecular dynamics, density functional theory, and machine-learning, for predicting phosphate-clay interactions, release kinetics, and plant uptake is also examined. Special attention is given to rhizosphere-scale processes, where root exudates, local pH fluctuations, and transporter activity interact with nanoclay carriers to trigger demand-driven phosphorus release. Agronomic studies demonstrate enhanced P-use efficiency, reduced nutrient antagonism, and improved crop performance under calcareous, saline, and drought-prone conditions. Rather than serving as an exhaustive survey of all nano-enabled phosphorus fertilizers, this article presents a forward-looking mechanistic roadmap integrating soil chemistry, rhizosphere biology, computational modeling, and data-driven design principles for nanoclay-phosphate systems. By emphasizing predictive and soil-specific fertilizer engineering, the review outlines future directions for developing intelligent phosphorus delivery platforms for calcareous agricultural systems.</p> Graphical Abstract <p></p>