Influence to the Rate of Nitrogen Fertilizer Application on Summer Maize Yield, Net Return,Agronomic Efficiency and Nitrogen Use Recovery

Effective nitrogen management remains one of the most challenging tasks for sustainable agriculture.This field experiment was conducted in a randomized design with three replicates to study the influence of nitrogen application rate on summer maize yield,net return,and agronomic efficiency of nitrogen application as well as nitrogen use recovery.The results showed that nitrogen application increased significantly biomass,grain yield and net return of summer maize in the range of 0～350 kg/hm2 N applied.The highest yield(9 897 kg/hm2)and net return(14 790 yuan/hm2)were obtained by the N treatment of 210 kg/hm2(N210).Compared with the treatment of no nitrogen application(N0),yield increased by 1 712 kg/hm2 or 20.9% with N agronomic efficiency of 8.2 kg/kg,net return increased by 2 132 yuan/hm2,and nitrogen use recovery was obtained by 38.6% at mean time.The relation of nitrogen application rate and yield,net return was fit by the quadratic function,and the highest rate and optimum rate of nitrogen application were calculated by 235 and 194 kg/hm2,respectively.This will provide theoretic and practice guide for rational fertilization for summer maize in southern region of Shanxi province.