And soybeans and wheat. And lets not forget the alfalfa which is used to feed all the cows out there too. They don't call the midwest "the breadbasket" for nothing.
Alfalfa, wheat are grown widely....
https://www.cdfa.ca.gov/statistics/
http://beef2live.com/story-states-produce-alfalfa-ranking-0-107298
https://www.statista.com/statistics/190376/top-us-states-in-wheat-production/