Length densities, occupancies and weights of apple root systems

The root systems of apple trees from five orchards ranging in age from 1.5-y to 14-y were sampled to depths of between one and two metres using soil cores. Although trees came from orchards which differed in soil-type, tree spacings and management, consistent patterns were found in root systems. In orchards of 4-y and older, roots of adjacent trees met so that soil volumes within the planting grids (i.e, tree spacings of approximately 5 m inter-row×4 m intra-row distances) were completely explored, although not completely occupied by roots. Mean root-length densities declined with depth for these orchards. In the 1.5-y orchard, roots from adjacent trees did not meet and root-length densities declined with radial distance from the stem as well as with depth.