Experience with foliar nutrition in apple orchard

In the period from 1996 until 2000 the technology of intensive foliar nutrition was applied in 60 ha of apple (Malus domestica Borkh.) orchards in the north-east of Slovenia. In these orchards, the trees were grafted on the M9 rootstocks and a reconstructed spindle into solaxe training system was used. The orchards were not irrigated. The fertilization of the soil depended on the soil and fruit analyses and the products intake of available nutrients. Taking into consideration all the factors, a foliar nutrition plan was prepared. If needed, certain improvements were made according to the analyses of leaves and precipitation in the current year. The foliar nutrition comprised the addition of macronutrients: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca) and micronutrients: zinc (Z), boron (B) and manganese (Mn). The fertilization of the soil was applied in accordance with the soil, leaf and fruit analyses. The richness of the soil and ratios between individual nutrients gradually improved. The foliar nutrition influenced the yield quantity and quality. The yield was doubled and the mean of five year-produce reached 70 tons per hectare. In spite of high yields there were no problems with alternative bearing. The analyses of soluble solids, firmness, fructose, glucose, sucrose, malic acid, citric acid, and mineral soil composition indicated that the produced fruits were of high quality despite greater yields.