SOIL CONDITIONS AND YIELD CAPACITY OF APPLE TREE ORCHARDS, CULTIVAR CHAMPION ARNO, DEPENDING ON OPTIMISED FERTILIZATION

Abstract

There exists a dual tendency concerning soil fertility and ecosystem productivity in present-day horticulture. On the one hand, due to the intensive use of land its degradation occurs, which leads to the worsening of agro-chemical properties, the contamination of the soils and the lowering of the plant yield capacity. On the other hand, the application of the scientifically grounded techniques of tillage and as well as the fertilization systems facilitates the increase of the mineral fertilizer efficiency, the preservation of soil fertility and the increase of crop yield capacity. The research results of the effect of the optimized fertilization system, based on the indicators of the chornozem opodzolic fertility and the yield capacity of Champion Arno apple trees in the Right bank Forest steppe zone of Ukraine, were considered. The trials were carried out in the experimental apple tree orchard of Uman national university of horticulture in the years of 2021–2023. Various fertilization treatments of apple trees, cultivar Champion Arno on rootstock MM.106, were the objects of the research. The results of the research showed a significant decrease in soil humus content in relation to a fertilization treatment, namely, from 0.01% to 0.06%. In the years under study, the content of nitrate nitrogen (according to nitrification capacity) in the soil in all studied treatments was lower than the optimal level. The content of phosphorus mobile compounds in the soil in all studied treatments was higher than the optimal level whereas the content of exchangeable potassium was higher only in a treatment when complete mineral fertilizer N120P90K90 was applied. The highest yield capacity of apple trees, cultivar Champion Arno, (33.4 t/ha) was recorded when calculated rates of NPK were applied and they were equal to the optimal levels with the additional nutrition in spring and autumn (nitrogen, boron and VuksalBioAminoplant were used); the fruit yield capacity was higher by 37% as compared with that of the untreated trees and it was higher by 24% as compared with the production control, where fertilizer N120P90K90 was applied annually. The application of the fertilizer rates, calculated based on the agro-chemical analysis of the soil, creates the optimal levels of the content of the doses of compounds and forms of nutrition element in a root layer which are available for the plants. These changes in the indicators of the chornozem opodzolic fertility favor more optimized mineral nutrition and, in turn, enhance the apple tree productivity.