Production, Mechanisms, and Performance of Controlled-Release Fertilizers Encapsulated with Biodegradable-Based Coatings

It is estimated that up to 50% of conventional fertilizers are lost once applied to agricultural soils (i.e., due to leaching and/or evaporation) or remain in the matrix due to poor nutrient use efficiency (NUE) by the crops. Controlled-release fertilizers (CRFs) might overcome both issues, and the use of extracted biobased polymers (or biodegradable materials) from organic waste (e.g., food losses or agrowaste) as coating agents is an ecological alternative aligned within the concept of a circular economy. This review is divided into two main sections: (i) sustainable CRF production (i.e., organic residues, value-added polymers used as capping agents, encapsulation methods) and (ii) a description of the nutrient release mechanism (i.e., a brief overview of nutrient release models applied to CRFs, and to the biodegradation process). The information provided in this manuscript will be relevant to guide future research in the field with the aim of promoting a sustainable approach in the use of fertilizers as well as other agrochemicals in agriculture.