【Objective】This paper was to explore the release characteristics of different forms of N
nutrients(NH4+-N,NO3--N,urea-N,DON
and total N)of uncoated slow/controlled-release compound fertilizer(CRF)and N uptake and use efficiency of rice.【Method】Water dissolution,soil leaching and pot experiment methods were started.【Result】Results showed that the dynamics of N release of CRF could be quantitatively described by three equations:the first-order kinetics
equation(Nt =N0(1-e-kt)),Elovich equation(Nt=a+blnt)and parabola equation(Nt=a+bt0.5).However,the imitation of the first-order kinetics equation was the best for different forms of N nutrien(tr=0.9569**～0.9999**).By Nt =N0(1-e-kt)equation,the release potentials of different forms N(N0 values)in the CRF were in accord with the accumulated nitrogen release amount and in the order of Total N>DON>Urea-N> NH4+-N>NO3--N in water,and Total N>NH4+-N>DON>Urea-N>NO3--N in soil.The rate constants of N release(k values and b values)of different forms of N was in the order of Total N>DON>NH4+-N>NO3--N in water.However,the k values was in the order of Urea-N>DON>NH4+-N>Total N>NO3--N;and the b values was Total N>NH4+-N>DON>NO3--N>Urea-N in soil.Compared to the common compound fertilizer(CCF),the N use efficiency,N agronomic efficiency and N physiological efficiency of CRF increased by 11.4%,8.32 kg·kg-1 and 5.17 kg·kg-1,respectively.The correlation analysis indicated that the ratios(between different forms of N and Total N in CRF)and N uptake by rice were positively significant of very significant.【Conclusion】Theimitationof the first-order kinetics equation(Nt =N0(1-e-kt))is the most practical for the release characteristics of different forms of N
nutrients.Compared to the only Urea-N of common compound fertilizer,different forms of N nutrients of CRF is in favor of rice.