The intention of this research project, which was supported within the "Bundesprogramm Ökologischer
Landbau", was to investigate in 2003 the situation on organic apple farms of nutrition of
leaves and fruits of the variety 'Topaz' and 'Elstar'. The contents of N, P, K, Ca and Mg were determined
in the leaves in April, June and August, micronutrients like Fe, Mn, Zn, B and Cu in April and
August. The number of flower-clusters per tree, the fruit-setting and the yield were investigated.
There were great differences between the orchards, the yield per tree varied between 3 and 24 kg,
depending from the age and height of the trees. Field trials were done to proof the effect of the foliar
fertilizers Vinasse, Biokal, Phytoamin, Wuxal Ascofol and Humulus. Effects on the fruit-setting (apples
per flower-cluster) were low after application for one season. The average fruit-weight did not
vary heavily, some differences were found in the percentage of flowerbuds in December 2003
