Macronutrients Click Open to view a picture. Close the current picture before viewing another. Generally speaking, symptoms first become evident in the older leaves at the base of shoots. Fruits, especially stone fruits, tend to be smaller and to mature earlier. As nitrogen increases above the optimum, fruit color is reduced and maturity is delayed.
Red cultivars are less red, and yellow cultivars tend to remain green.
In apples and pears flavor and storage life are reduced. Besides direct toxic effects, other physiological problems, such as corking and bitter pit, can occur in apples and pears because of higher nitrogen levels that are not in balance with calcium levels. Deficiencies severe enough to produce visual symptoms are rare in fruit trees. When they do occur, symptoms may appear first as limited and slender terminal growth with young expanding leaves that are abnormally dark green. The young leaves' lower sides, especially along the margins and main veins, frequently show purplish discoloration.