Omenapuun juuristosta

Authors

• Jouko Vuorinen Maatalouden tutkimuskeskus, Maantutkimuslaitos

DOI: https://doi.org/10.23986/afsci.71467

Abstract

This study of the root systems of apple-trees was carried out on four Finnish soil types in the years 1955—57. Trees of several ages were investigated in Pikkola orchard at Kangasala, where there was sand soil (Figures 1—5) and silt soil (Fig. 8). The same investigations concerning fine sand soil were made at Häme Agricultural Experiment Station at Pälkäne (Figures 6 and 7), concerning heavy clay (Fig. 9) in Koivula orchard at Hirvensalo, and concerning other soil conditions in the orchard of the Institute of Pomology at Skierniewice in Poland (Fig. 10). Field work was carried aut on a sector of 30—180° in 5, 10 and 20 cm. layers and in 30 or 50 cm. belts. The soil was taken out on a sieve and the roots cleaned by hand without water. The roots were classifield into two groups, above and below 2 mm. For other determinations soil samples were taken. This investigation concerning the spreading of the root system is a part of a more extensive study of soil profile in orchards to elucidate some problems about orchard soil fertility. In this connection a knowledge of the root systems of the trees is a very important question. Regarding apple-trees, the results of this investigation can be used in planning steps for better management of the orchard soil. Especially mulching, manuring and fertilizing have a very close connection with the root system. In establishing new orchards it is important to know the relation between the roots and the soil. With regard to these considerations some conclusions have been made: Conclusions The root system spreads relatively more rapidly than the crown of the tree in young trees and it can reach 1—1.5 meters outside the crown circle. The root system of the apple-tree usually distributes itself to an equal depth in the soil, which in young trees consists of 40—50 cm., and which goes deeper with age. Under the best conditions (in finer finesand) the root system of older trees reaches a depth of one meter (Figures 6 and 7). In compact soils the root system does not go so deep (e.g., in heavy clay. Fig. 9). In sand soil the root system concentrates itself in the lower layer of the mould horizon and clearly avoids the dry sand in the subsoil (Figures 4 and 5). In clean cultivated orchards the root system avoids the tilled layer. The thickness of this rootless horizon varies between 5—20 cm. Sod and mulch seem to provide good conditions for the roots; thus the root system below these rises to the soil surface. The mean layer of the root systems of apple-trees begins at a depth of 10 cm and reaches to 50 cm. The root density in this layer is usually the greatest. In most cases the root density is almost equally distributed over the layer 0—50 cm., except for the inner circle of radius 0—90 cm.