[ig1]

Simple Answer: We can't produce oil (we discover it), we can produce crops. We're pretty good at it.

Complex answer: If demand for crops goes up then farmers can grow more crops. Although it's hard to see if that's happening right now as corn ethanol subsidies and corn import taxes completely distort that market. If you want to produce corn ethanol you buy domestic corn as you can get US gov subsidies for it, you don't get those subsidies if you use imported corn, so naturally US produced corn ends up disproportionately in fuel production. Also it's worth noting that DDG is a byproduct of corn ethanol production, and DDG is used as animal feed. So it's misleading to think that corn used for fuel production is pulling it completely out of the food chain.