Nano-Fertilisers in Rice Production: A Critical Review of their Role in Enhancing Nutrient Use Efficiency, Yield and Sustainability

Abstract

Rice (Oryza sativa L.) is the primary caloric staple for more than half of the world's population, yet its production is increasingly constrained by the inefficiency of conventional fertilisation practices, mounting environmental burdens, and the imperative to sustain yields under a changing climate. Nano-fertilisers — nutrient-bearing materials with at least one dimension in the nanometre range — have attracted considerable scientific interest as a means of improving nutrient use efficiency, reducing environmental losses, and supporting sustainable rice production. This narrative review synthesises peer-reviewed evidence published between 2015 and 2026 on the formulation, mechanisms of action, agronomic performance, soil health implications, and sustainability credentials of nano-fertilisers in rice systems. The literature search was conducted since January 2026 to present, using the following electronic databases: Web of Science, Scopus, Google Scholar, and PubMed for general agricultural science and environmental literature. Key categories discussed include nano-urea, zinc oxide nanoparticles, selenium-based nanomaterials, nano-phosphorus carriers including hydroxyapatite, and silicon nanoparticles. Evidence from field and controlled experiments across South Asia, East Asia, and Africa demonstrates that nano-fertilisers can maintain or enhance grain yields whilst reducing the recommended dose of conventional nutrients by 25–30%, with attendant reductions in greenhouse gas emissions and nutrient leaching. Micronutrient nano-fertilisers, particularly nano-zinc applied as a foliar spray or soil amendment, improve grain zinc content substantially, offering a promising pathway for biofortification alongside yield gains. Silicon nanoparticles show particular efficacy in mitigating abiotic stresses including salinity, drought, and heavy metal toxicity. Despite these advances, concerns remain regarding phytotoxicity at supra-optimal doses, impacts on soil microbial communities, regulatory frameworks, cost of production, and scalability for smallholder farmers. The review identifies key knowledge gaps and calls for standardised field-scale evaluation protocols, long-term soil safety assessments, and integrated policy support to enable responsible commercialisation.