Improving the Productivity, Quality, and Storability of ‘Katja’ Apple by Better Orchard Management Procedures

Abstract

This 4-year study at the Kivik research station, southeastern Sweden (≈55°N), investigated optimal orchard management procedures to improve tree growth, yield, fruit quality, and storability in the important early season apple cultivar ‘Katja’. Two procedures (one standard, one novel) were applied within pruning, weed control, fertigation, and thinning, yielding a total of 16 different combinations (treatments). Tree vegetative growth, yield, fruit size, fruit color, firmness, soluble solids concentration, malic acid, nitrogen and calcium content, and percentage fruit with storage rot (Pezicula malicorticis) were evaluated for all 16 treatments. Changing to the novel alternative in only one or two of the areas did not produce significant improvements in all investigated parameters. The optimal treatment consisted of radical winter pruning + summer pruning (novel), bark mulching (novel), fertigation with 0.13 g N (standard), and hand thinning after full bloom (novel).