How Are Plants & Animals Affected by Sulfur?

Sulfur in Plant Nutrition

• Although sulfur is not one of the three plant macronutrients, it is an important nutrient for growing healthy plants. Sulfur promotes the development of certain enzymes and vitamins in plants as well as the production of proteins and chlorophyll, which is vital to photosynthesis. It helps grow vigorous plants with strong roots and high seed production. Sulfur also improves a plant's resistance to cold.

Sulfur in Animal Nutrition

• Because sulfur is a component of vitamin A and some essential amino acids, it is also an important mineral in an animal's diet. Vitamin A plays an important role in eye, skin and bone health. Sulfur-heavy amino acids promote the production of the proteins that make up wool and hair. Sulfur also bonds with a number of heavy or toxic metals in the body and helps lower the levels of these metals, countering their damaging effects.

Extra Sulfur in the Environment

• Sulfur occurs naturally in the environment, supplied by rainwater or through the decomposition of animal manure and yard waste such as grass clippings. However, some agricultural practices deplete the soil of sulfur faster than it can be replaced naturally and fertilizers containing sulfur are applied. Also, sulfur is used in insecticides, fungicides and rodentcides. Animals are either directly exposed to higher levels of sulfur during application or through the consumption of the treated plants. Distilleries use sulfuric acid during fermentation, and the fermented grain, with its new, higher level of sulfur, is often fed to livestock.

Negative Effects

• Additional sulfur in the soil can improve crop yields, seed production and overall plant health. However, increasing sulfur for animals can have negative effects. Grant Crawford of the University of Minnesota Beef Team concluded that a high concentration of sulfur leads to poor weight gain in cattle. Additionally, in ruminating animals, sulfur is converted into hydrogen sulfide. When the animal belches out the hydrogen sulfide, it also inhales some into the lungs, which affects the central nervous system, causing seizures, convulsions and death. Also, according to a 2005 report form the National Research council, high levels of sulfur in an animal's diet may lead to deficiencies of copper and selenium.