My first thought was "When the corn grows as high as an elephant's eye" but, no--of course, that's from Oklahoma, from which we also learn that "the farmer and the cowman should be friends."

Then I realized that "I'm as corny as Kansas in August, high as a flag on the Fourth of July ..." but, of course, Kansas is not Iowa, and that song is from South Pacific.

Anyway, bravo, Iowa. You deserve a musical of your own, now.