Applications and perspectives of using nanomaterials for sustainable plant nutrition

Nanotechnology opens a large scope of novel applications in the fields of plant nutrition needed to meet the future demands of the growing population because nanoparticles (NPs) have unique physicochemical properties, i.e. high surface area, high reactivity, tunable pore size, and particle morphology. Management of optimum nutrients for sustainable crop production is a priority-based area of research in agriculture. In this regard, nanonutrition has proved to be the most interesting area of research and concerns with the provision of nano-sized nutrients for sustainable crop production. Using this technology, we can increase the efficiency of micro- as well as macronutrients of plants. In the literature, various NPs and nanomaterials (NMs) have been successfully used for better nutrition of crop plants compared to the conventional fertilizers. This review summarizes these NPs and NMs into macro-, micro-, and nanocarrier-based fertilizers and plant-growth-enhancing NPs with unclear mechanisms, describing their role in improving growth and yield of crops, concentration/rate of application, particle size, mechanism of action if known, toxic effects if any, and research gaps in the present research. Moreover, future research directions for achieving sustainable agriculture are also discussed in the appropriate section and at the end in the concluding remarks section.