ISHS Acta Horticulturae 383: Mineral Nutrition of Deciduous Fruit Plants
EFFECT OF FRUIT LOAD ON LEAF NUTRIENT CONTENT OF APPLE TREES |
| Authors: | A. Sadowski, M. Kepka, F. Lenz, G. Engel |
| Keywords: | biennial bearing, defruiting, leaf sampling, diagnosing nutrient status |
| Abstract:
Leaf nutrient contents of bearing and non-bearing trees have been compared in two experiments. In the experiment carried out in the years 1965–1972 in Lyczyn, Central Poland, on 15–22-year-old biennially bearing 'Yellow Transparent' apple trees, in non-bearing years leaf N, Ca and P content was lower while K and Mg higher than in bearing years. In Klein-Altendorf, Rhineland, Germany, trees of three apple cultivars were defruited after bloom in 1983, the third year after planting. Defruiting resulted in a decrease of leaf N, Ca, Mg and P contents in all cultivars under study but did not affect leaf K content. Significant differences in leaf nutrient contents due to cultivar were also found as well as interactions of fruit load and cultivar. It has been concluded that absence of fruits resulting from biennial bearing, spring frost or any other reason may alter leaf nutrient concentration to such extent that leaf analysis may lead to false conclusions. Therefore, for diagnostic purposes, sampling leaves from non-bearing trees must be avoided. As leaf nutrient concentrations may differ depending on cultivar, for a reliable diagnosis of nutritional status of an orchard, leaves of at least two cultivars should be sampled. | |
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