Nanocomposite Reduces Volatile and Aqueous Reactive Nitrogen Losses From Soil Compared to Conventional and Alternative Fertilisers

ABSTRACT Reactive nitrogen losses from agriculture contribute substantially to greenhouse gas emissions, water pollution and ecosystem degradation. Controlled‐release fertiliser technologies offer potential solutions, yet few comprehensively evaluate performance across multiple nitrogen loss pathways and soil types. This study evaluated the environmental performance and agronomic efficacy of urea‐doped amorphous calcium phosphate (U‐ACP) nanoparticles compared to conventional urea across three contrasting soil types (sandy, sandy loam, clay loam) using lettuce ( Lactuca sativa ) as a model crop. U‐ACP nanoparticles (20–100 nm) were synthesised and characterised for dissolution kinetics in simulated soil environments. Controlled glasshouse experiments (8 weeks, 100 kg N ha − 1 application rate) quantified gaseous emissions (ammonia, nitrous oxide, nitric oxide), aqueous leaching losses, soil biochemical properties, plant nitrogen uptake and functional gene abundances for nitrogen cycling processes. U‐ACP demonstrated significantly reduced reactive nitrogen losses across all pathways and soil types. Cumulative ammonia volatilisation decreased by 53%–57% in sandy and sandy loam soils compared to conventional urea ( p < 0.001), whilst nitrous oxide emissions declined by 19%–27% across all soil types ( p < 0.001). Total nitrogen leaching concentrations were 44% lower in sandy soils where losses are typically highest ( p < 0.001), with ammonium leaching reduced by 71%–85% across soil types. Cumulative gaseous nitrogen losses decreased by 20%–48% depending on soil type. Despite these substantial reductions in nitrogen losses, U‐ACP maintained comparable plant biomass whilst achieving 52%–89% higher nitrogen uptake index across soil types ( p < 0.001). U‐ACP also supported enhanced soil microbial functionality, with significantly elevated complete ammonia oxidiser (comammox) and alkaline phosphatase ( phoD ) gene abundances ( p < 0.05). Calcium phosphate‐based nanocomposite fertilisers offer a viable pathway towards sustainable intensification of agriculture by simultaneously reducing environmental nitrogen pollution whilst maintaining or improving crop productivity across diverse soil conditions.