GROWTH AND YIELD CAPACITY OF APPLE TREE, CULTIVAR CHAMPION ARNO, DEPENDING ON OPTIMIZED FERTILIZATION

Abstract

Applying fertilizers is a powerful way to regulate the productivity of apple trees. Rational mineral nutrition activates photosynthesis, growth processes, the formation and differentiation of generative buds. It promotes the achievement of regular high yields, improves the quality of fruits, and enhances the winter hardiness of fruit trees. It is one of the key components of intensive cultivation technologies for fruit crop plantations. During the period of intensive growth of trees, when they build up a large vegetative mass and for this absorb a large amount of nutrients, there is often a need to apply fertilizers, but it is not always possible to carry out this measure in an intensive garden. Therefore, with the help of foliar fertilization, it is possible to improve the nutrition of fruit plants. The results of the studying of the effect of soil fertilization and top dressing on the growth indicators and yield capacity of the apple tree, cultivar Champion Arno, grown on opodzolic chornosem in the Right-bank Forest steppe zone of Ukraine, were discussed. The research was conducted in the experimental apple orchard of Uman National University of Horticulture in 2021–2022. Various fertilization and feeding schemes for Champion Arno apple trees on MM-106 rootstock were the subject of the research. In the years under study, it was found that the stem diameter increment of the trees ranged from 10.7 to 16 mm and it was significantly dependent on fertilization. The average shoot growth increment in the plots of all examined fertilization treatments exceeded the control by 12% for soil fertilization, 15% for foliar feeding, and 33% for the application of a biostimulant in conjunction with foliar nitrogen and boron in spring and autumn, with optimized soil nutrition. A similar trend is observed in the total length of growth increment depending on the examined variants. On the average, over the years of the study, the yield capacity of the trees on the optimized fertilization background exceeded the production control by 4.6% and the absolute control by 31.8%. In spring and autumn, top dressing with nitrogen and boron, in addition to the application of a biostimulant-anti-stress agent, contributed to a 21% increase in the yield capacity as compared with the control (tree treatment with water).