Unless I am very much mis-informed, most tractors run on diesel, not gasoline. Thus, it would be biodiesel, not ethanol, that farmers would need to produce to fuel their equipment. If they do have any gasoline-powered equipment, I am pretty sure that diesel-powered alternatives exist. Farmers would be well advised to ditch their gasoline-powered equipment and switch to diesel, as they will undoubtedly realize some fuel economies, and leave better options open for themselves in the future.

I think because of the high octane content of ethanol it could be used as a diesel engine fuel with some modifications.