A pilot project to create super enzymes as catalysts to break down agricultural waste to create biofuel went so well that Shell plans to do it on a commercial scale.
One major fuelstock here would be the leftovers from corn, the husk and the ears. Right now, most of the energy, water, fertilizer, etc. that goes into growing corn is wasted, because only a small part of the plant, the kernel, is edible. All the rest gets wasted. That’s why cellulosic ethanol is so important, we would be creating “renewable petroleum” from that which is now wasted.
A sugar refinery in Maui is already doing something similar, they create biofuel from bagasse, the leftovers from sugar cane processing, and use it to power their farm equipment. Certainly large scale corn farmers could do the same.