Perspectives in nanocomposites for the slow and controlled release of agrochemicals: Fertilizers and pesticides

Abstract

Agrochemical represented mainly by fertilizers and pesticides are vital inputs for agricultural production. However, their conventional application in field is poorly effective, with significant losses due mainly to volatilization and/or lixiviation of soluble agrochemicals. In some cases, the application exceeds two times the optimal quantity, meaning that other undesired consequences take part, such as environmental contamination or production of greenhouse gases. A considerable scientific effort has been made to develop viable systems for the controlled or slow delivery of agrochemicals, in order to adjust the nutrient availability in soil to minimal doses required for pest control or to levels needed by plants. Besides other technologies, the association of soluble materials containing fractions of minerals with very high surface area has shown to be an effective way for the optimization of agrochemical application, where the cation-exchange capacity (CEC) of minerals plays an important role. Then, the association of mineral structures (high CEC clays and layered double hydroxides, etc.) opens a new research field in the tailoring of nanocomposites, where the properties of minerals, polymers, and additives that are associated with agrochemicals (considered as the active moiety of the nanocomposites) can produce novel properties to the release control. Therefore, this chapter reviews the underlying principles in controlled or slow release of agrochemicals, the fundamentals of key technologies, and the current perspectives in the production of new materials, comparing their potential with conventional materials regularly produced.