Are you sure that $1,000 isn't old or for grazing land or something? Decent corn fields are selling for $7k+ an acre in most parts of the country.
Anyway, if biofuels go away, food prices will drop dramatically. Biofuels eat up 40% of all US corn supplies each year, which exerts incredible pressure on all agricultural output. Less land being used to produce food equals rising food prices. And it goes all the way up and down the chain, since harvested crops are often turned into animal feeds which then drives up the cost of raising farm animals. So biofuel is the main driver. After that I would say increased meat demand in Asia. It takes a lot more calories of grain to make a steak or chicken breast than you get back in return.