ISHS Acta Horticulturae 564: IV International Symposium on Mineral Nutrition of Deciduous Fruit Crops
INFLUENCE OF DIFFERENT RATES OF NITROGEN ON FRUIT QUALITY, YIELD AND PHOTOSYNTHESIS OF 'FUJI' APPLE |
| Authors: | E. Fallahi, W. Michael Colt, B. Fallahi, I.-J. Chun |
| Keywords: | higher density, Malus x domestica, mineral nutrition, postharvest physiology |
| Abstract:
The influence of various rates of ground-applied nitrogen (N) on yield, fruit quality, leaf photosynthesis, and leaf mineral concentrations in 'BC-2 Fuji' apple (Malus domestica Borkh.) trees was studied over several growing seasons. Fruit skin red color decreased as the rate of N increased. Under the environmental conditions of this experiment, annual ground application of N for optimum fruit quality should be somewhere between 31.8 and 99.8 g/tree. Considering yield and fruit quality attributes (color, firmness, fruit size, and soluble solid concentrations), optimum leaf N should be between about 2.00% to 2.10 % dwt (preferably 2.05% dwt) during an "off-year" or light-crop-year and between about 2.22% to 2.38% dwt (preferably 2.30% dwt) during an "on-year" or heavy-crop-year for production of high quality 'Fuji' fruit. In general, leaf K decreased while leaf Mg and Mn increased with increase in N application. Fall application of N often resulted in lower leaf N, thus, better fruit color. Other fruit quality attributes were not consistently affected by time of N application. Leaf photosynthesis decreased between mid-June and mid-August. Trees receiving 31.8 g N/tree/year had lower leaf photosynthesis than those receiving higher rates of N. | |
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