It is a challenge to keep track of all the raw materials ballooning in price around the world. The latest obscure entry to the list is none other than potash. This humble material is one of the three essential nutrients used in fertiliser, along with nitrogen and phosphorus. Reserves under ground are ample – 100 years worth or more – but geographically concentrated. Just 12 countries produce potash, and almost four-fifths of reserves lie in Canada, Belarus and Russia.