Innovative NPK Fertilizers based on Polyacrylamide and Polyvinyl Alcohol with Controlled Release of Nutrients

Abstract The aim of the present work was the preparation and properties evaluation of two innovative fertilizers based on multicomponent polymers characterized by a controlled release of nutrients. One method was based on a multi-component liquid containing different amounts of microelements NPK 12-5-6 fertilizers with polyacrylamide hydrogel beads. The second method concerned the cross-linking of biodegradable polyvinyl alcohol with multi-component NPK fertilizers. Polyacrylamide-based compositions with the highest amount of NPK salts as well as polyvinyl alcohol-based fertilizers in dense gel form, based on 60 phr crosslinking concentrate have shown optimal properties. Regardless of the type of fertilizers used, their components were released slowly. The obtained fertilizers were classified according to the kinetics of nutrient release. Fertilizers made from polyacrylamide based fertilizers have been classified into a group of controlled release fertilizers (CRF), while those made from biodegradable environmentally friendly polyvinyl alcohol have been defined as slow released fertilizers (SRF).