Excessive wheat surpluses

Nature 
Periodically a combination of good weather and other factors gives rise to surpluses of wheat stocks which seriously depress the price of wheat on the international market and disrupt the economies of exporting countries. The accumulation of such surpluses has been a recurring feature of world markets for 50 years.
Claim 
Wheat surpluses are used by North American and European countries as a political weapon. Past occasions have seen threats to withhold surplus wheat exports from countries whose own stocks are inadequate. Due to the international political benefits of having excess grain, domestic governmental policies may be to support wheat over-production.
Strategy(ies) 
Value(s) 
Type 
(E) Emanations of other problems