The Influence of Nitrogen Fertilization, Season of Application, and Orchard Floor Management on Fruit Quality and Leaf Mineral Content of 'Golden Delicious' Apple Trees

Abstract

‘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.