This poses an interesting question.  Looking at a fact sheet from IL FB (http://www.maconcfb.org/UCR%20FAQ%202008-03-31.pdf) I see

"If an in-state grain elevator resells the bulk of its grain to in-state users (e.g.: livestock feeders, feed mills, ethanol plants, millers) then it is improbable that regulators would consider deliveries to that elevator from within Illinois to be interstate moves and those trucks would not be subject to registration"

I don't know where my local elevator is selling its grain, but I am pretty sure the beans are being processed in Illinois, and I do know a couple years ago every kernel of corn they bought at my nearest facility went to a local ethanol plant.

So as I read the regs, I am exempt from UCR at this time.