Symptoms
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.
Reasons
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.
Iron deficiency made worse by
High pH
Water logged soils
Calcareous soils
High copper, manganese or zinc soils
Iron is important for
Essential for photosynthesis and plant metabolism
Thus important for early leaf development, strong growth and crop productivity