Fe deficiency is marked by pale green and yellow color of the youngest leaves, while the veins remain darker green (intercostal chlorosis).
Sometimes the youngest leaves contain no chlorophyll at all and are white in color then.
Iron deficiency
Iron deficiency mainly occurs in calcareous soils and in other soils with a high pH-value due to the low availability of Fe.
In specific clay soils Fe becomes fixated and deficiency is the consequence.