The objective of the research is to determine the pattern of reducing and increasing the distance from bole of a plant to the boundary of zone with main mass of roots of apple tree in soil depending on its age. Analytical processing on each characteristic package of experimental data was resulted in empirical relationship. For each functional relation, statistical characteristics of their validity and accuracy of approximating the experimental data were established. It was determined that the distance of the main mass of roots from bole of apple tree on different measured indicators (quantity and length of roots, as well as the quantity of root cuts) and species, cultivars and rootstocks can be approximated by the corresponding dependencies. Analysis enabled to reveal a high degree of convergence (magnitude of reliability of approximation was 0.931) for the values of the distance from the bole of apple tree to the zone where situated 68.2 % of root mass, which were determined by the terms of “quantity of roots” and “root length”. Uniformity of functional relations indicates not only the sustainability of morphometric structures of root systems of trees but shows the opportunity of using obtained relationships in practical calculations for decision making on selecting the optimal scheme of planting and layout of drip emitters in under-crown and outside-crown space in order to handle growth and development of root systems of apple trees. Thereby, knowing the age of an apple enables to determine the distance for boundaries of zone contained the main mass of plant roots from its bole as a percentage of the average radius of its root system. The obtained data enable to determine minimum required zone for artificial moisturizing.
Keywords: geometric parameters of the root system, apple tree, main mass of roots, bole, parameter, functional relations, under-crown and outside-crown space.
