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Fertilizer utilization rate has been the focus of academic and government in China,Urea,as the most important nitrogen fertilizer,easily occurs volatilization,leaching and runoff,Now,slow/controlled release urea can effectively solve this important problem,However,the materials used in slow-release urea may usually cause high cost and environment pollution,due to their non-biodegradability and complex preparation processes.Therefore,In this project,Polyphenol,a natural compound,will be used on slow-release urea because it is biodegradable and cheap.We develop a solvent-free method and molten Urea state to prepare between the three(Poly(dimethyldiallylammonium chloride)solution(PDDA),polyphenol,metal ions)and the built-in network slow-release urea by the similar as gel action based on coordination chemistry.The structure was characterized by FT-IR and SEM.The slow/controlled release properties in water/soil and pot culture experiments were studied.The results show that this method is easy to prepare slow-release urea,and has a good slow-release effect.It has a better promotion to seed germination rate,seedling rate and so on.This slow-release urea is non-toxic,safe and biodegradable,theoretical basis will be provided for the research and appliance of the development of the technology of melting urea by spraying granulation.