The point is that there is limited cultivable land, and farmers can switch crops once or twice a year, so they switch from edible corn to ethanol corn to other crops as prices fluctuate. As corn (and soybeans, as it can also be used for ethanol) becomes more scarce, livestock farmers have to switch to other crops to feed their cattle.

Flooding in Bangladesh caused a local shortage of rice, and there are other factors at play (increased asian prosperity, oil prices, speculation on commodity futures) but what in the past would have been an Indian surplus readily exported there now faces certain conditions, and others like Pakistan suffer as well.

E85 Fueling Station Locations
Ethanol Plants

Gas stations don't indicate total use (industrial users get their gas in bulk, etc.) but that's some indicator there.