In order to provide evidence for the fine synthesis and scientific application of urea-formaldehyde (UF)

the study was to investigate the relationships between the nutrient release characteristics of UF and the driving factors

and the effects of optimized products on rape (Brassica campestris L.) growth. The response surface methodology was used to investigate the response of urea formaldehyde molar ratio (U/F)

temperature and time to the slow available nitrogen and activity index (AI) of UF. Meanwhile

the nitrogen (N) release rate of UF and soil N supply were measured in the rape pot experiment. The results showed that the quadratic polynomial mathematical model of the slow available N and AI of UF were established and both of them were significant. The slow available N and AI of UF fertilizer were mainly affected by U/F (X1)

followed by reaction time (X2). The optimal parameters for UF production

which with the highest AI and maximum slow available nitrogen content were: U/F 1.48

reaction temperature at 45.26 ℃ and reaction time for 1.71 h. Under these conditions

the slow-release effective nitrogen reached 12.63%

with AI as 67.86%. Meanwhile

the N release rate of UF in soil was slowly and soil inorganic N contents were increased with UF fertilization

especially in the later rape growth period. Compared with treatments of urea at the same rates of N application

the mixture of urea application and UF at 7∶3 ratio increased rape yields by 23.93%～24.50%. However

nearly the same yield occurred with single fertilization of UF. Moreover

even the rate of N application was reduced 20%

the mixture treatment still increased the rape yield by 8.38% compared to the high amount urea treatment. Eventually

the mixture of Urea and UF

were the best mode for gaining greatest yields of rape and higher N use efficiency.