Abstract: 【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 nutrient（r＝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】The imitationof 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.

Key words: Slow/controlled release compound fertilizer, Nitrogen form, Release kineticsNitrogen use efficiency