THE INFLUENCE OF NITROGEN-FERTILIZATION, SEASON OF APPLICATION, AND ORCHARD FLOOR MANAGEMENT ON FRUIT-QUALITY AND LEAF MINERAL-CONTENT OF GOLDEN DELICIOUS APPLE-TREES

'Golden Delicious' apple trees were grown under 3 orchard floor management systems (grass sod, vegetation control to July or vegetation control year-round) and 3 rates of nitrogen (30, 60 or 180 kg N ha-1) applied in the spring (1980-83) or the fall (1984-87). Fruit at harvest from grassed plots tended to be firmer, lighter in color, higher in acidity, higher in K and slightly higher in Ca compared to those from non-grassed plots. Leaf N was lower and leaf K was higher from grassed plots than non-grassed plots. High rates of N tended to give greener fruit, higher leaf N and lower leaf K. A lower leaf N content was observed in 1985-87 than in 1981-83 and is assumed to be an effect of time of N application rather than one caused by tree factors.