Go to the nearest municipal/community airport.

It's almost CERTAIN there will be some fellows around who'd love an excuse for a flight. Offer to pay their fuel cost for an hour to take you up, circle the corn field for a while. If the plane's large enough, they'll probably have friends/other pilots around that'll come along for the ride, and offer an extra pair of eyes.

Failing that, go to the nearest "edge" of the field perpendicular to the rows, and start walking, looking down each row like you'd look down grocery aisles trying to find your mom when you were a kid.