Agricultural Horizons: Research, Technology and Sustainable Development Vol. 1

Low nutrient and agrochemical use efficiency remains a persistent constraint in crop production, and interest has grown in whether engineered nanomaterials (ENMs) can improve the precision with which nutrients, protectants and stimulants are delivered to seeds and plants. This chapter reviews the evidence for the use of ENMs in seed quality enhancement, nutrient delivery, crop protection, abiotic stress mitigation and crop monitoring, covering metal and metal oxide nanoparticles, carbon dots, silica nanoparticles and polymer-encapsulated formulations.

The literature was searched systematically and studies were classified by evidence level, from in vitro assays through to commercially available products, so that proof-of-concept findings are not conflated with field-validated performance. Polymer-encapsulated nano-fertilisers have been reported to release nutrients over extended periods and to improve nutrient recovery relative to conventional soluble equivalents in specific crop and soil combinations, although reported gains vary widely and few have been reproduced across seasons or sites. Nano-enabled pesticide formulations can reduce the amount of active ingredient applied while maintaining efficacy under the tested conditions, but effects on beneficial organisms, residues and resistance selection are not well characterised.

Carbon dots have been reported to influence water uptake by seeds, germination rate and photosynthetic parameters, though their properties depend strongly on precursor, synthesis route and purification, and apparent effects can arise from residual molecular fluorophores rather than from the particles themselves. Nanoparticle seed priming has improved germination and vigour indices in aged seed lots in several species, but artificial ageing is not equivalent to natural storage, and short-term germination stimulation should not be reported as extended seed longevity.

Overall, selected ENMs show promise under laboratory, controlled-environment and limited field conditions. Consistency across environments, scalability, long-term environmental and human safety, regulatory feasibility and comparative cost-effectiveness against best available conventional technologies remain insufficiently established. Priorities for future work include minimum characterisation and reporting standards, harmonised experimental controls, independent replication, validated residue methods, multi-season field evaluation and life-cycle assessment.