Effects of Irrigation and Urea Types on N Utilization,Yield and Quality of Maize

【Objective】The objective of this study is to investigate the effects of application rates of normal urea and controlled release urea on N utilization, yield and quality of summer maize under different irrigation levels. 【Method】Five nitrogen rates and two irrigation levels were designed to investigate the effects of water-nitrogen coupling on dry matter accumulation, leaf area index, grain yield, dry matter yield, the N uptake and grain protein yield of the summer maize in a randomized design. 【Result】 At the same irrigation level, compared with the control, nitrogen application enhanced dry matter accumulation and leaf area index. Dry matter accumulation and leaf area index of maize applied with controlled release urea were lower than those applied with normal urea before anthesis, but the situation was just contrary after anthesis. Increasing the nitrogen fertilizer rates enhanced total N uptake of maize, and excessive nitrogen increased the proportion of vegetative organs, thereby reduced the grain quality. At the same nitrogen level, dry matter accumulation, leaf area index and yield were increased with irrigation at filling stage, while N uptake amount before and after anthesis, grain protein content and yield were decreased with irrigation at filling stage. The coupling effects of water and controlled release urea on N uptake, grain yield and protein yield of maize were obviously higher than those of waterand normal urea. 【Conclusion】In conclusion, compared with normal urea, whatever with or without irrigation at filling stage, controlled release urea can coordinate the growth of shoot to get higher grain yield, and increase of soil moisture is beneficial to improve the superiority of controlled release urea.