Sulfur is an important nutrient for organisms, being an key constituent of certain amino acids, proteins, and other biochemicals. Plants satisfy their nutritional needs for sulfur by assimilating simple mineral compounds from the environment. This mostly occurs as sulfate dissolved in soil water that is taken up by roots, or as gaseous sulfur dioxide that is absorbed by foliage in environments where the atmosphere is somewhat polluted with this gas. Animals obtain the sulfur they need by eating plants or other animals, and digesting and assimilating their organic forms of sulfur, which are then used to synthesize necessary sulfur-containing biochemicals.

In certain situations, particularly in intensively managed agriculture, the availability of biologically useful forms of sulfur can be a limiting factor to the productivity of plants, and application of a sulfate-containing fertilizer may prove to be beneficial. Sulfur compounds may also be associated with important environmental...