Symptoms
Sulfur is not as mobile as nitrogen within the plant. For that reason symptoms start on younger leaves and progress to older plant parts.The leaves are stiff and curled downward. They develop an interveinal chlorosis turning yellowish green to yellow. Stems, veins and petioles look purple.
When nitrogen is deficient, leaves are small and uniformly pale green to yellow in color. Symptoms are first seen in the old leaves and gradually progress to new growth. The plant appears thin and upright.
With severe deficiency the old leaves become completely yellow or turn brown before dropping from the plant. Stems and veins look purple. Growth is clearly stunted.
Reasons
Sulfur deficiency (right) compared to nitrogen deficiency (middle) and optimum supply (left)
