Influence of Foliar Application of Nitrogen on Tree Growth, Precocity, Fruit Quality, and Leaf Mineral Nutrients in Young ‘Fuji’ Apple Trees on Three Rootstocks

The influence of three foliar applications and one ground application of nitrogen on tree growth, precocity, fruit quality at harvest and after storage, and leaf mineral concentrations in young ‘Fuji’ apple (Malus domestica Borkh.) trees on three root-stocks were studied. Trees that received a total of 197 g urea (90.6 g actual N) as a ground application over three growing seasons had greater trunk cross-sectional area (TCA), yield per tree, and yield efficiency than trees which received one of three rates of foliar applications. Trees receiving ground-applied or foliarly-applied urea at the highest rate had the heaviest fruit. Fruit firmness was greatest in the lowest foliar treatment. Ground application resulted in greater than average leaf N in 1994 and the greatest leaf Ca and lowest percentage leaf dry weight, leaf K, Zn, and Cu in both 1993 and 1994. Trees on M.9 NAKBT337 were more precocious and smaller in size than those on M.7 EMLA. Trees on M.7 EMLA had lower yield efficiency and greater leaf K than trees on either M.9 NAKBT337 or M.26 EMLA.