04 Oct 2006

Some Things to Know About Potassium

Some Things to Know About Potassium

Potassium (K) is everywhere in nature. It can be found in oceans and seas, in the soil, in rocks and minerals, and in plants and animals. It is essential to all forms of life -- human, animal, and plant. There are no substitutes for it.

Potassium is the third most abundant mineral in the human body. Only calcium (Ca) and phosphorus (P) occur in greater quantities. Most body K -- nearly 90% -- is found in the major organs and tissues, including muscles, skin, and the digestive tract. Conditions such as high fever, loss of body fluids, stress, shock, or other trauma can lead to K loss from our bodies that can endanger our well-being. Doctors sometimes prescribe K supplements to overcome such losses.

Proper diet is the best guarantee that K intake is sufficient to support good health. Nature provides a bountiful supply of K, in meats, dairy products, fruits, nuts, and vegetables. For example, a potato, baked with skin, contains more than 800 milligrams (mg) of K, and a whole banana contains 450 mg. Eating a balanced diet is the number one defense against illnesses and other factors which can lead to K shortages.

Plants grown for food take up and use large quantities of K. Potassium is one of the three “primary” plant nutrients -- along with nitrogen (N) and P -- needed by plants. For example, a corn crop producing a grain yield of 12.6 metric tons/ha (200 bu/A) removes about 23 kg (50 lb) of K in the grain. Forages such as alfalfa harvested for hay also remove large quantities of K.

Why do plants require so much K? For the same reasons as people. Potassium is essential for normal plant functions such as photosynthesis, protein formation, and water use. Plants cannot complete a normal life cycle without sufficient K.

Fertilizer is added to soil to replace the K removed in harvested crops and to enrich infertile soils. The most common source is the K mined from naturally occurring ore bodies. Valuable minerals were deposited as water evaporated from pre-historic oceans and K salts crystallized to become the beds of K ore (potash) being mined today. About 93% of the commercially produced K is used in agriculture for food production. The remainder is used for industrial purposes and for products common in the home. Animal manure, greensand, and some by-products also contain relatively low amounts of K and can be applied to the soil as a fertilizer for crops. However, they can be profitably transported only for short distances.

World consumption of potash has exceeded 30 million tons annually in recent years. Canada is the world’s leading producer, followed by Russia, Belarus, Germany, and the U.S.A. Other important K-producing countries include Israel, Jordan, Brazil, and China.