ISHS Acta Horticulturae 114: Symposium on Research and Development on Orchard and Plantation Systems
EFFECTS OF PLANTING DENSITY, POSITION OF LEAVES IN THE TREE CROWN AND TYPE OF LEAF ON THE ACCUMULATION OF NUTRIENTS IN APPLE LEAVES |
| Authors: | J.L. Barrera-Guerra, K. Slowik |
| Abstract:
Studies on McIntosh and Macspur apple trees were carried out in a high density orchard where two levels of fertilization, under irrigation and without irrigation, were used. Information was obtained from six selected rows with four different planting densities (one, two, three and five row beds with 1 908, 2 640, 3 030 and 3 465 trees per ha, respectively). For foliar analyses samples were taken from the outer and inner parts of the tree and, at each place, from terminal shoots and from spurs. In both cultivars the N leaf content was significantly lower in leaves from the rows with more competition for light. Phosphorus was not greatly affected. K content was higher in the leaves from rows with more competition for light. Ca content was not affected by planting density, although in some cases it showed a tendency to be lower in leaves from the more dense planting. Fe was affected by widespread branching. Effects of planting density on Mg, Mn and Cu were indefinite. The K/Ca, N/Ca and K + Mg : Ca ratios appeared high because of the low Ca content. In McIntosh, K, Mg and Fe contents as well as K/Ca and K + Mg : Ca ratios were significantly higher in the inner part of the tree crown, while in Maospur in the same position only K and Fe contents were higher. As regards the type of leaf, both cultivars showed higher contents of N, P and K as well as higher N/Ca, K/Ca and K + Mg : Ca ratios in terminal leaves. Conversely, Ca, Mg, Mn and Fe contents were higher in spur leaves. | |
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