Urea–hydroxyapatite-montmorillonite nanohybrid composites as slow release nitrogen compositions

Abstract Nanohybrid composite was developed by the encapsulation of urea modified hydroxyapatite nanoparticles into the nanolayers of montmorillonite. The nanohybrid composites were synthesized by two approaches; solution phase synthesis and liquid assisted grinding techniques and were tested for their slow release nitrogen in soil. The characterization results revealed the successful realization of a nanohybrid containing urea modified hydroxyapatite nanoparticles encapsulated in montmorillonite. The release behavior of urea in different pH values indicated a slow and sustained release of nitrogen. The rate of release of N was significantly lower in the nanohybrid composite prepared using solvent assisted grinding techniques. Pot trials conducted using Oryza sativa (rice) demonstrated a significant yield enhancement with the novel plant nutrient system. Montmorillonite nanohybrid composite thus prepared can be used as an environmentally friendly fertilizer formulation which could be extended to solve one of the major problems faced in the global fertilization of low nitrogen use efficiency in agriculture.