SULFUR

Unlike the other secondary nutrients like calcium and magnesium (which plants take up as cations), S is absorbed primarily as the SO₄²⁻ anion. It can also enter plant leaves from the air as dioxide (SO₂) gas.

Characteristic Odors

Sulfur is present in several organic compounds that give the characteristic odors to garlic, mustard and onion.

Amino Acids & Proteins

Sulfur appears in every living cell and is required for synthesis of certain amino acids (cysteine and methionine) and proteins.

Photosynthesis

Sulfur is also important in photosynthesis and for winter crop hardiness.

Chlorophyll Formation

Although S isn't a constituent of chlorophyll, it's still vital in chlorophyll formation.

Seed Production

Sulfur aids in seed production.

Nitrogen Fixation

Leguminous plants need S for efficient nitrogen fixation.

Sulfur deficiency symptoms

Symptoms of deficiency can vary across crop species, but similarities exist for how nutrient insufficiency impacts plant tissue color and appearance. Nutrient deficiencies are commonly associated with the physical location on the plant (i.e., whether the symptoms are primarily observed on older versus newly formed plant tissue), but these symptoms can spread as the severity of the deficiency progresses.