EFFECT OF LONG TERM SOIL AND LEAF NITROGEN APPLICATIONS TO APPLE cv. JONAGOLD AND BOSKOOP ON NMIN IN THE SOIL AND ON LEAF AND FRUIT QUALITY

A long term nitrogen trial was carried out with apple trees (Malus domestica Borkh.) cv. ‘Jonagold’ and ‘Boskoop’ on EM9 rootstock.
Comparisons were made between trees receiving no nitrogen at all and trees receiving a yearly nitrogen dose as a soil application of 60 kg N and 90 kg N and trees receiving a yearly dose as a leaf application of 30 kg N and 60 kg N, or a yearly soil application of 30 kg N combined with a leaf application of 30 kg N. The influence of the different nitrogen levels on Nmin pattern in the soil, on the productivity of the trees over a ten year period and on leaf mineral composition is discussed in this paper.
It was only after some years that a clear nitrogen deficiency level could be measured in the trees of the untreated plot.
Differences in nitrogen level could not prevent alternate bearing in Boskoop but reduced the tendency in Jonagold.
The influence of nitrogen on fruit quality and on storage behaviour is discussed.

IV International Symposium on Mineral Nutrition of Deciduous Fruit Crops

T. Deckers, H. Schoofs, E. Daemen, C. Missotten, R. Hähndel

nitrogen nutrition, Nmin, leaf analysis, foliar nutrition

https://doi.org/10.17660/ActaHortic.2001.564.31