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| Authors: | A. Sadowski, E. Jadczuk |
| Keywords: | sour cherry nitrogen, fertilisation, herbicide strips, sward, fertiliser distribution, leaf N, growth, yield, fruit size |
Abstract:
In the years 1989–1995 an experiment was carried out in an orchard on a fertile alluvial soil maintained with sward in alleyways and herbicide strips along the rows.
When narrow (1 m) herbicide strips were maintained, no response of ‘Schattenmorelle’ trees to nitrogen fertilisation (60 kg N/ha) was found during four years after planting; leaf N concentration was optimal irrespective of the treatment and rangied from 2.54 to 2.74 % d.m.
Starting from the 5th year (1993), leaf N concentration of unfertilised trees dropped below 2.30 %. This accompanied a decrease in tree growth in the period 1993–1994, followed by decreased yield in the 6th (1994) and 7th (1995) year.
The effect of N fertilisation on cropping was related mainly to a greater tree size and partly to improved fruit set.
The absence of response in the first years is explained by the abundant release of available N within herbicide strips where a major part of the tree roots of young trees was located.
For older trees, when roots expanded over the whole area, including beneath the sward, nitrogen supply decreased and the need for fertilisation appeared.
Wide (3 m) herbicide strips, without fertilisation, only slightly improved N nutrition.
Fertilisation in herbicide strips (1 m wide, covering only 20 % of the area) was ineffective, as well as fertilisation in the first 3 years only.
Sour cherry leaf N concentration of 2.30% may be considered as a lower limit of the optimal range for diagnostic purposes.
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