A variant of this is already happening in the developing world: cash crops for international markets (tobacco, cotton, coffee, etc.) being favoured over food for the national/regional market.  
The consensus in Eastern Arkansas-The Delta, is that cotton
will be planted turnrow to turnrow (meaning, everywhere possible).

Corn and rice will be cut back-at least 20%, with soybeans
(no fertilizer needed)filling the gaps.

James