Nitrogen fertilization and elemental composition affects fruit quality of ‘Fuji’ apples

Abstract

In 1989 to 1995, five rates of nitrogen (N) fertilizer were applied to ‘Fuji’ apple trees grafted on ‘Delicious’ and ‘Granny Smith’ interstems and grown on M.26 rootstock to determine fruit quality and yield. Fruit weight was increased by N fertilizer rate, but fruit production was not influenced appreciably by rate of N fertilizer, for the one year (1994) it was observed. Highest fruit quality was achieved with the lowest N fertilizer rate of 25 lbs.A^‐1 (28.4 kg.ha^‐1). Fruit quality was negatively related to N in leaves and fruit peel and cortex as well as leaf boron (B), fruit peel copper (Cu), magnesium (Mg) and fruit cortex Mg, and manganese (Mn) for both interstems. Lower rates of N fertilizer were related to lower concentrations of leaf and fruit N, “redder”; fruit skin color, greater fruit firmness and soluble solids concentration, higher fructose levels, and a lower incidence of bitter pit and scald than the higher rates of 100 or 150 lbs N A^‐1 (113.6 or 170.5 kg N ha^‐1).