[Objective] The aim was to explore scientific application of N fertilizer for summer maize species.[Method] A test was designed to research effects of N quantities on Zhengdan No.958,Xundan No.20,Nonghua No.101 and Xianyu No.335 in terms of yield,economic benefits,accumulated nitrogen and use efficiency of N fertilizer.[Result] The increase of N fertilizer improved yields of summer maize dramatically.Specifically,with low N quantity,yield and net revenue of Zhengdan No.958 reached 18.19% and 3 158 yuan/hm^2,respectively,and yields and net revenues of Jundan No.20,Nonghua No.101 and Xianyu No.335 were 17.31% and 2 642 yuan/hm^2,25.03% and 3 726 yuan/hm^2,17.41% and 3 182 yuan/hm^2,accordingly.With N quantity increased,agricultural efficiency of Zhengdan No.958 reduced significantly and the agricultural efficiencies showed little differences among Xundan No.20,Nonghua No.101 and Xianyu No.335.[Conclusion] In practice,Zhengdan No.958 is suitable to be applied with N at low quantity,and Xundan No.20,Nonghua No.101 and Xianyu No.335 are suitable to be applied with N at high quantity.
