Status of Zinc Deficiency
Corn is the only field crop presently grown in Kentucky that has shown zinc-deficiency symptoms and that has definitely given a response to zinc applications. Isolated instances of zinc deficiency have been reported from nearly every area of the state. However, the difficulty appears to be more prevalent in soils of the central Bluegrass and the western Pennyrile regions.
Considerable variation in respect to zinc deficiency has occurred within these regions, characterized by no consistent pattern. Corn producers in these areas particularly should watch this crop closely for deficiency symptoms during the period 4 to 6 weeks following planting.
Miller, Harold and Phillips, Shirley, "Zinc Deficiency in Corn" (1966). Agronomy Notes. 206.