Effect of nitrogen application at the jointing stage on grain yield and quality of Ningmai 16.

In this study,field experiments were conducted during 2008-2009 growing season to evaluate the effect of nitrogen fertilizer application to wheat variety 16 at the jointing stage on grain yield and quality.Nitrogen fertilizer was used at nine different rates of 0,37.5,75.0,112.5,150.0,187.5,225.0,262.5 and 300.0 kg·hm-2,respectively.The result showed that nitrogen fertilizer application at the jointing stage had a significant and positive effect on yield,and the average yield increased by 29.4% over the control.Nitrogen fertilizer with a rate of 225 kg·hm-2 resulted in the most significant yield improvement,with a net yield increase by 2281.0 kg·hm-2.However,if the amount of nitrogen fertilizer application was continued to increase,the grain yield would be declined.Nitrogen fertilizer application resulted in 14% and 19% increase in number of spikes and kernels per spike over the control.Protein content,wet gluten content,dough stability time and extensibility were also increased with nitrogen application increasing.In conclusion,Nitrogen fertilizer application of 225 kg·hm-2 at jointing stage would be sufficient to obtain optimum grain yield and better quality for Ningmai 16.