Effect of nitrogen and iron nutrition on some quantitative and qualitative characteristics in apple cv. ‘Granny Smith’

To evaluate the effect of different levels of nitrogen and iron on some quality indices and yield parameters of "Granny Smith" apple a factorial experiment, in a completely randomized block design with three levels of nitrogen (0, 144 and 288 g ammonium nitrate per tree( and three levels of iron (0, 1500 and 3000 mg Fe-EDDHA per tree) as soil application, was conducted during 2015. Nitrogen application increased chlorophyll index and yield efficiency. The highest chlorophyll index (58.77) and yield efficiency (0.889 Kg.m-2) were observed in 288 g/tree ammonium nitrate. Iron application increased pH of fruit juice and fruit iron concentration, and decreased leaf K concentration. Positive correlation between total antioxidants and leaf Fe concentration (r = 0.84), a* parameter and leaf Fe concentration (r = 0.68), leaf K content and leaf N content (r = 0.69), fruit K content and fruit N content (r = 0.74), leaf N and fruit N content (r = 0.66) was observed. In conclusion, nitrogen application at 288 g/tree was more effective in improving the mentioned characteristics. Iron nutrition had no much impact and seems that more concentrations of iron are required to a greater effect.