Azotnoe pitanie yabloni.
1994
Kulesha V. | Shafranek R.
In the first experiment, ten-year Wealthy apple trees were given 0, 120, 240 or 360 kg N/ha every year for ten years. In another experiment, ten-year McIntosh apple trees received 0, 60 or 120 kg N applied either to the whole area of the orchard or to the herbicide strips only. All trees were grown in herbicide treated strips with grassed alleyways. The N content of Wealthy apple leaves increased with the increasing rate of N. Leaf N content of unfertilized trees dropped below 2 per cent. This was accompanied by a significant yield reduction while among particular N rates no significant differences were detected. Fruit dry matter content and storage ability decreased with increasing N rates. In the second experiment, the leaf N content of the untreated McIntosh trees decreased. No significant differences in the leaf N content, fruit yield and size, dry matter or storage ability were found due to different N rates or position of N application (whole area or herbicide strips only). Therefore, applying N to the herbicide strips only it is possible to save 50 per cent of the fertilizer. The rate of 60 kg N/ha has not only an economic aspect but also an ecological one as this rate does not threat the environment. The rate higher than 80 kg N/ha may result in NO concentrations in ground waters beyond the limit of tolerance (10 mg N/dm exp (3)).
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