Sulfur (S) in planst is a constituent of certain amino acids. Since S is also involved in chlorophyll production, deficiency symptoms in wheat are similar to nitrogen (N) chlorosis (i.e. a genearl chlorosis of the leaf). However, S deficiency does differ from N deficiency in that the whole plant is pale with a greater degree of chlorosis in the young leaves. The pattern of chlorosis in the new leaves may show gradation in intensity from tip to base, but they quickly become totally chlorotic and take on a light yellow color.

Under severe deficiency and as the plant ages, other symptoms besides paling can appear on old leaves. Leaf tip necrosis can occur, but this may be indicative of nitrate accumulation rather than a direct effect of S deficiency. Extreme S deficiency can result in a lack of head formation.

Symptoms of S deficiency in the field resemble N deficiency with a light yellowing of the leaves. However, unlike N deficiency, these symptoms are predominantly on the younger leaves. S deficiency is most marked with the use of mono-ammonium phosphate and diammonium phosphate, which contain no S and high levels of N. When ordinary super-phosphate, which contains approximately 12% S, is applied, S deficiency is uncommon, except late in the season on very sandy soils in high rainfall areas.