Tools for Nano-Enabled Agriculture: Fertilizers Based on Calcium Phosphate, Silicon, and Chitosan Nanostructures

The Green New Deal requires a profound transformation of the agricultural sector, which will have to become more sustainable and ensure universal access to healthy food. Thus, it will be essential to introduce radical technological innovations. Nanotechnologies have the potential to produce a significant boost to the improvement of the food system. Within this context, in the next years, a strong challenge will need to be faced regarding developing new and more efficient uses of nutrients in agriculture, being the nutrient use efficiency (NUE) paramount in sustaining high crop productivity without depleting biodiversity, and altering both the natural and agricultural systems. Nutrients leaching causes environmental pollution and water eutrophication, while nutrient excess favors pest and weed widespread. Therefore, it will be mandatory to improve plant nutrition efficiency without affecting agricultural productivity and economic sustainability. A promising alternative consists of the introduction of the so-called nanomaterial enhanced fertilizers and plant growth stimulators. Such innovation includes nanotechnological solutions that can improve nutrient delivery for a more finely tuned, accurate, and saving-resources distribution of nutrients. This review provides a critical view of the latest advances in nanofertilizer research, mainly referring to nano-hydroxyapatite, silica nanoparticles, and chitosan-derived nanostructures.