Fertilizers

This chapter describes the main features of fertilizers, which are the products used to supply nutrients to plants. Currently, these products not only contain nutrients but may also enhance the capacity of plants to absorb nutrients. Traditionally, most mineral fertilizer production was based on nonrenewable and sometimes strategic resources. This can constrain future agricultural sustainability and food security. Thus, special attention is paid nowadays to fertilizer production based on circular economy approaches. Most of the fertilizers used in agriculture are those for supplying primary macronutrients, i.e., N, P, and K. Nitrogen fertilizers are very soluble, and their selection and application should be intended to minimize losses. Phosphorus fertilizers are distinguished mainly by their solubility which determines how and when they can be used. Potassium fertilizers are highly soluble, but losses are not limiting since K is retained in soil. Deficiencies of micronutrients are usually controlled with forms bound to organic compounds (complexes or chelates) which solves immobilization reactions or limitations to be absorbed by plants under certain soil conditions.