Potassium is the seventh most abundant element in the Earth's crust, and is the third major plant and crop nutrient after nitrogen and phosphorus. It has been used since antiquity as a soil fertilizer (about 90% of current use). Potash is important for agriculture because it improves water retention, yield, nutrient value, taste, colour, texture and disease resistance of food crops. It has wide application to fruit and vegetables, rice, wheat and other grains, sugar, corn, soybeans, palm oil and cotton, all of which benefit from the nutrient's quality enhancing properties.
Demand for food and animal feed has been on the rise since 2000. The U.S. Department of Agriculture's Economic Research Service (ERS) attributes the trend to average annual population increases of 75 million people around the world. Geographically, economic growth in Asia and Latin America greatly contributed to the increased use of potash-based fertilizer. Rising incomes in developing countries also was a factor in the growing potash and fertilizer use. With more money in the household budget, consumers added more meat and dairy products to their diets. This shift in eating patterns required more acres to be planted, more fertilizer to be applied and more animals to be fed -- all requiring more potash.
The world's largest consumers of potash are China, the United States, Brazil and India. Brazil imports 90% of the potash it needs.
Potash imports and exports are often reported in "K2O equivalent", although fertilizer never contains potassium oxide, per se, because potassium oxide is caustic and hygroscopic. See Potassium oxide in fertilizers.
The value of potash has soared in recent years, currently at $480 USD a tonne (March 2012) the prices are expected to reach $1,500 by 2020.