Last July, Uralkali quit the cartel it was forming with Belaruskali, and which controlled around 40% of the world’s trade in potash, saying it would seek to maximize its own volumes. It warned that prices could fall as much as 25 percent by the end of 2013 to less than $300 per tonne.

2 months later, China‘s sovereign wealth fund (CIC) acquired a 12.5 percent stake in Uralkali, following a pattern of China’s acquiring direct control of overseas mineral companies to keep price and supply stable. Uralkali’s decision to dismantle one of the world’s two big potash cartels pummeled shares of companies that produce potash and heralded a price war for the key crop nutrient...