Urea, a rich source of nitrogen, is widely used as an agricultural fertilizer in developing areas, unfortunately its rapid decomposition leads to waterway eutrophication and nitrogen dioxide emissions, limiting the amount of N absorbed by crops.

Urea-hydroxyapatite nanohybrids for slow release of nitrogen. Source: ACSAs a result, farmers must apply more fertilizer in a cost-inefficient and environmentally damaging process to boost food production.

Researchers from the UK and Sri Lanka have devised a more sustainable approach to fertilizer application. Urea solubility is reduced by incorporation into a matrix of biocompatible hydroxyapatite nanoparticles. The nanofertilizer slowly releases N in water, 12 times slower than urea itself.

Field tests on rice farms showed that the nanohybrid formulation halved fertilizer requirements. The researchers contend their development could improve the yield and environmental sustainability of agriculture.