Productivity and fruit quality of apple in single-row and full-field planting systems

Abstract In a planting-system trial with the apple cultivars ‘Karmijn de Sonnaville’ and ‘Golden Delicious’, both on M.9 rootstock, single rows were compared with full-field systems over 10 years. In the former, tree rows were bordered on either side by tractor alleys, in the latter by foot-paths. Four systems were compared: 1. (1) single row at 3.50 × 1.43 m (standard); 2. (2) single row at 2.75 × 0.80 m; 3. (3) full-field at 2.00 × 1.25 m; 4. (4) full-field at 1.50 × 0.80 m; giving tree densities of 2000, 4545, 4000 and 8333 per ha, respectively. Fruit production per tree increased with tree age. The higher the density, the faster the production rose and the lower the final production level. This was in accordance with ultimate tree size. On a hectare basis, production also rose faster with increasing density, but here the maximum production level was higher, the greater the density, with one exception; System 3 was better than System 2, indicating an important effect of tree arrangement. A higher production in the full-grown phase was achieved with greater tree densities (except again for Systems 2 and 3). Increasing the tree density led to lower production per unit of growth in some cases, but this was not true for yield per unit of tree-volume. Fruit size of ‘Karmijn’ remained on a satisfactory and about equal level in all systems. With ‘Golden Delicious’, however, fruit size was inadequate in Systems 2 to 4 in some, especially dry, years. This was not the case in the full-grown phase when normal rainfall occurred and the necessary expertise with regard to pruning and thinning was utilized. System 4 gave the highest productions per ha of large apples and System 1 the lowest. Fruit colour of ‘Karmijn’ remained satisfactory in all systems, although System 2 lagged somewhat behind. The hectare-production of well-coloured fruits approximately followed total production, System 1 being the least productive and Systems 3 and 4 the most. Increasing the tree density had no effect on sugar or acid content, nor on taste or storage behaviour of the fruits. The same was true for mineral composition of leaves and fruits.