Chapter 5 - Methods for controlled release of fertilizers

Abstract

Controlled-release fertilizers (CRFs) are advanced form of fertilizers that release nutrients into the soil in a controlled way that matches the need of a growing crop. The advantage of CRF is that it significantly delays or extends its availability for plant uptake and use after application. This may occur by a variety of mechanisms like coating with semipermeable or impermeable coatings, protein materials, or other chemically decomposable forms, by slow hydrolysis of water-soluble low molecular weight compounds or by occlusion. The coating material controls water penetration and availability of nutrients in forms preferred by plants and helps in maximizing crop yields.