Abstract: Waste foamed polystyrene was used as the main materials to produce coated fertilizer of urea. Ethyl acetate or toluene was the solvent. Dibutyl phthalate was selected as plasticizer to reduce the brittleness of polystyrene. SBS resin was used as enhancer to improve the adhesion of polystyrene film. The concentration of coating solution was 12 %, containing 3 % plasticizer and 1 % enhancer. The amount of coated materials was 10 %. Dissolution rate of nitrogen in the water and soil was determined. The initial dissolution rate of slow-release fertilizers in water was lower than 40 % and the cumulative dissolution rate in soil was significantly lower than that of no-coated urea.

Key words: plasticizer, enhancer, polystyrene, coated-fertilizer, release performance