Nanotechnology promotes the R&D of new-generation micronutrient foliar fertilizers

Foliar fertilizers have attracted increasing attention over the last few decades as they offer the most efficient way to correct micronutrient deficiencies and enhance the product yield and quality of crops and plants. The micronutrients are essential to physiological functions in plant metabolism, and leaf uptake has been extensively studied as a biological process, however, the mediating factors are still unsolved. This review presents the current efforts of chemical engineers and nanomaterial scientists to solve the problems by taking the advantages of nanotechnology and designing and developing new-generation long-term foliar micronutrient fertilizers. The important physiological functions of the most important micronutrients (zinc, manganese, copper, and iron) have been briefly reviewed to illustrate the significance of the relevant research. Current foliar fertilizers have then been assessed in terms of their solubility, morphology and surface properties. The new screening criteria of new-generation micronutrient foliar fertilizers have been put forward from the viewpoints of material engineers, and our recent research efforts using nanotechnology to design and develop new foliar fertilizers have been summarised. Finally, our opinions for further development of long-term micronutrient foliar fertilizers have been proposed based on the nanotechnology