EFFECT OF CHERRY NITROGEN FERTILIZATION ON THE CONTENT OF MINERALS IN THE LEAVES AND SOIL

The objective of studies carried out in years 2002–2009 was to determine the effect of nitrogen fertilization on the content of mineral components in the leaves of cherry trees and on the changes in assimilable components in the arable and subarable soil layers. Cherry orchards were established in spring 1999, 2001 and 2002 with the application of ‘Łutówka’ cultivar, type IR2. In the orchards planted in 2001 and 2002, trees were spaced in 4 × 1.3 m density (1920 trees · ha-1). In the orchard planted in 1999, the tree density was 4 × 2 m (1250 trees · ha-1). Orchards were planted on the same field, on greybrown podzolic soil created on boulder clay sandy loam. In spring 2002, in each of the planted orchards, nitrogen fertilization was applied in the doses of 0, 50 and 120 kg · ha-1. Our studies have shown that the fertilization with the differentiated nitrogen doses carried out for many years exerted an effect on changes in the soil chemical properties, in comparison with the initial soil status in the year 2002. Contents of assimilable phosphorus and potassium, both in the arable and the subarable magnesium decreased in a lesser degree, while in the orchard planted in 2002, magnesium showed even an increase. However, it must be stressed that in spite of the lapse of time, the soil contents of phosphorus and magnesium, in comparison with the critical values, were on a high level, while potassium showed an optimal or high level, with pH value from 5.7 to 6.6. General analysis revealed that nitrogen fertilization, as well as the age trees exerted an influence on the content of components indicating that N fertilization exerted an increasing effect on nitrogen and magnesium contents, but it decreased the contents of potassium and calcium.