Abstract: The nitrogen liquation of coated urea（LP30）were resolved based on reaction rate theory with culture experiment method under different temperatures. The results showed that the nitrogen liquation of coated urea（LP30）could be obeyed to the first-order reaction model. Liquation rate constant（k）was dependent on temperature. When the liquation rate constants changed from 0.0081～0.0425, activation energy was 75733 J.mol-1 in range of 10℃～25℃.The days of temperature switch method could apply and estimate the liquation amount of coated urea based on reaction rate theory in natural conditions.

Key words: Reaction rate theory, Days of temperature switch（DTS）, Coated Urea, Liquation character