Grew up in Indiana literally surrounded by fields, which often contained corn. Also ran track and cross country in Indiana. Running on a hot August day when the corn was up was miserable, both because of the humidity exacerbated by the corn, and the fact that 2m tall corn blocks whatever breeze might otherwise be blowing.
What should we replace the corn with?
We don't necessarily need to replace it with anything. The problem isn't the corn. The problem is it's too humid. We're a grownup species, we can deliberately change the environment if we really want to.
The problem is the corn subsidies. If they weren't distorting the market, crops other than corn would be viable in many places currently growing corn.