(Reuters) - Potash was once of little interest outside the agricultural sector, but the crop nutrient has become a hot item, with pricing having outperformed other commodities during the boom and the subsequent downturn.
A small coterie of companies control the vast majority of global potash production.
Here are a few facts about potash:
* Potash is the common name for various compounds containing potassium, which are used mainly as fertilizers.
* Potash pricing has been extremely volatile for years. The price of the nutrient began the last decade below $150 a ton and soared above $1,000 a ton during the commodity boom in 2007-08. It has since crashed to about $350 to $375 a ton levels, but is still well above its historical average.
* Potassium, identified in the fertilizer world by the chemical symbol K, is one of the three main macro nutrients required by plants, along with nitrogen (N) and phosphate (P).
* Potash helps improve a plant's disease resistance, crop quality and increases yields. It is the only potassium fertilizer source; there are no practical substitutes.
* Only 12 countries produce potash. Canada, Russia, Belarus and Germany account for more than 75 percent of global supply.
* Eight companies currently control more than 80 percent of global supply: Potash Corp of Saskatchewan, Mosaic Co, Agrium Inc, K+S, Uralkali, Silvinit, Belaruskali, and Israel Chemicals.
* Two marketing conglomerates control more than 60 percent of global potash exports. Canpotex is the overseas potash marketing arm of Potash Corp, Mosaic and Agrium, while Belarussian Potash Co is the export agent of Uralkali and Belaruskali.
Reporting by Euan Rocha; Editing by Frank McGurty