IMPACT OF PREPLANTING FERTILIZATION ON THE LEAF NUTRIENT CONTENT OF YOUNG SOUR CHERRY TREES

The objective of the present study was to determine the impact of seven variants of organic and mineral preplanting fertilization on the content of the main macronutrients (N, P, K, Ca, Mg) in the leaves of sour cherry trees, Erdi Bötermö cv., grafted on two types of rootstocks - seedling forms of Mahaleb (IK-M9) and Droganyellow bigarreau. The investigation was carried out during the period 2001-2003 in an experimental orchard at the Institute of Agriculture, Kyustendil. There was no significant effect of the different preplanting fertilization variants on leaf nitrogen content. The trees on rootstock Droganyellow bigarreau responded more pronouncedly to phosphorous and potassium fertilization, which corresponded to the higher leaf phosphorous and potassium content, compared to those on IK-M9. In all variants, there was a trend for a higher calcium concentration in the leaves of the trees on Droganyellow bigarreau. Leaf magnesium level decreased over experimental years, which was more strongly manifested by the trees on Droganyellow bigarreau, whereas in the variants on the Mahaleb rootstock it was of higher values.