Comparison of Foliar and Soil N Applications on Growth of 'Golden Delicious' Apple

This experiment was carried out to compare the effectiveness of foliar and soil N applications on plant tissue and soil nitrogen status and growth of 'Golden Delicious' in Zanjan, Iran. The experiment included a control (no N) and 3 N treatments where the same amount of N was applied once every two weeks starting on early June. Nitrogen (as urea 46% N) was applied by: 1) foliar sprays only, 2) soil surface addition only, and 3) soil and foliar combination (every month either soil or foliar). Apple growth was influenced by N application, but there were no significant differences among different N treatments. There was no significant difference between fruit mineral concentration (except N). All N treatments significantly increased leaf N concentration, compared to the unfertilized control, but there were no significant differences between N treatments. Foliar application increased reserve N concentration in both fruit and leaf Leaf N concentration varied during the growth season. Both soil N application alone and soil-foliar combined N applications significantly increased the vegetative growth (shoot length), while foliar N application alone did not affect new shoot length. At the end of the growing season, all N treatments had a higher shoot length, while the control treatment had less shoot growth. Foliar-applied N can be more efficient than soil applied N. A combination of soil-applied and foliar applied N is recommended for N-nutrient management.