ISHS Acta Horticulturae 512: XXV International Horticultural Congress, Part 2: Mineral Nutrition and Grape and Wine Quality
FRUIT MINERAL CONCENTRATION AND QUALITY OF 'GALA' APPLES AS AFFECTED BY RATE AND TIMING OF FERTIGATED N |
| Authors: | D. Neilsen, G.H. Neilsen, J.W. Hall |
| Keywords: | firmness, fruit N, P, Ca, Mg, K, Malus domestica, N fertigation, soluble solids, titratable acidity |
| Abstract:
The effects of rate and timing of fertigated N on fruit quality were assessed for Gala apple. An experimental block of Gala on M·9 rootstock, planted in spring 1993 at a 1.25 × 3 m spacing was subjected to treatments involving the application of 3 rates of fertigated N (12, 24, 48 g N/tree/year) applied during 5 periods (0–2, 3–7, 8–12 weeks post bloom; 2 weeks preharvest; and last irrigation). Rate of fertigated N had a greater effect on fruit quality at harvest, 1994–97, than on fruit mineral concentration. Flesh firmness and titratable acidity decreased and soluble solids and starch index increased in response to higher N. Fruit colour was decreased in 1995 only in response to a higher N rate. Fruit firmness was the quality parameter most affected by alterations in timing of N-fertilization. N applications immediately following bloom decreased fruit firmness in years of low but not in years of high cropping intensity. Fruit Ca concentration and overall fruit quality remained high regardless of the rate or timing of N-fertilization. | |
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