Membrane-encapsulated controlled-release urea fertilizers based on acrylamide copolymers

About 40–70% of the applied urea fertilizer is lost to the environment, causing serious pollution. Controlled‐release technology is useful in increasing the efficiency of fertilizer urea as well as in checking environment pollution. Four laboratory‐level controlled‐release urea fertilizers were formulated based on polymers which are soil conditioners and then evaluated for their slow‐release property. Urea was coated with the copolymer of acrylamide and divinylbenzene/N,N′‐methylenebisacrylamide /tetraethyleneglycol diacrylate or pentaerythritol triacrylate and sealant materials (wax and polystyrene). Urea coated with co‐polymer of acrylamide‐tetraethyleneglycol diacrylate was found to be having a better slow‐release property among the systems prepared. © 1996 John Wiley & Sons, Inc.