Biodegradable Polymer Encapsulated Nickel Nanoparticles for Slow Release Urea Promotes Rhode Grass Yield and Nitrogen Recovery

There is a pressing need for the development of sustainable and high-use efficiency nitrogen (N) fertilizer formulations to ensure food security and climate change mitigation. Recently, nanotechnology has shown a potential to contribute to sustainable agrochemicals production by the coating of organic and inorganic nanomaterials. Here we explored the use of nickel encapsulated nanoparticles with different biodegradable coatings such as: starch, polyvinyl alcohol (PVA), gum arabica, gelatin, molasses and paraffin wax (PW) to improve the physical properties of conventional N fertilizer under soil plant system. The results revealed that coating urea granules with nickel encapsulated nanoparticles significantly increased N availability and thereby the dry matter yield of Rhode grass. The coating materials reduce the dissolution and enhance the impact resistance of granules. The UC-5 treatment containing starch, PVA, molasses, PW and Ni-NPs gives the best results in the terms of release rate (77.96% of urea release after 120 min relative to 100% urea release for uncoated granule), crushing strength (70 ± 0.27 N) and Rhode grass dry matter yield (58.55 g pot⁻¹). The results showed that the UC-5 treatment greatly enhanced soil mineral nitrogen relative to uncoated and urea coated with NiO-NPs only. Therefore, this formulation would be considered for improving plant N uptake under sustainable and clean agriculture. Graphical Abstract: [Figure not available: see fulltext.]