Smart-delivery systems in Nano-Enabled Agriculture. The current state-of-the-art on nanohydroxyapatite

The development of nanotechnologies in the last 25 years has considerably improved, even revolutionized, many technology and industry sectors: information technology, medicine, transportation, energy, environmental science, and everyday products, as well. Nano-enabled agriculture (NEA) describes the application of nanotechnology in agriculture to improve the performance of agrochemicals. NEA mainly focuses on improving the agrochemical uptake efficiency by crops, enhancing plant growth and food safety, and mitigating the environmental impacts of agriculture. However, nanotechnology applications in the agricultural chain are still marginal and have not yet made it to the market in comparison with other industrial sectors. Compared to other productive sectors, the main reason for the slow development of the NAE is due to the specific peculiarities of agriculture. The use of renewable materials deriving from plant and animal waste biomass to produce nanosized delivery systems in NEA represents a crucial step towards the fulfillment of a circular economy. A paradigmatic example concerns the valorization of hydroxyapatite (nHAP). The paper provides updates on the use of nHAP for sustainable crop phosphorus fertilization and the development of nanohybrids to provide other macro-nutrients loaded on the nHAP structure.