Corn yields in the US remained relatively flat from the Civil War until the end of World War II.

“from about the end of World War two that line just turns up and just almost in a linear fashion rises to two hundred bushels per acre per year and I think what a lot of people erroneously assumed is oh it's the goddamn GMO well actually no not at all GMO didn't even kick in until that number was a hundred and sixty it was nitrogen-based fertilizer crop rotation industrial farming meaning the ability to actually use machine to not just have a farmer out there doing something it was selective breeding crossing”