CONTROLLED RELEASE PLANT NUTRIENTS

摘要

Plant nutrients that are released in soil over a controlled period of time a re comprised of plant nutrient particles containing urea and on the surface of the particles a water insoluble, biodegradable, interpenetrating polymer network comprised of a biuret, a urethane and tung oil; more specifically, a n interpenetrating network comprised of the reaction product of the urea and a n isocyanate reactive with urea, the reaction product of the isocyanate and an alcohol reactive with isocyanate to form a urethane, and the reaction produc t of the urethane and tung oil. A method of making the controlled release plan t nutrient conveniently and economically is also disclosed.