I don't think you are going to save any money by paying off a 0% loan. If you can pay it off then do so. Then take the monthly payment you were paying and invest in something that pays you interest.
If you want to pay it off so you can cancel your insurance, I wouldn't do it. I don't know how much your tractor is worth but what happens if it gets stolen or damaged and you don't have insurance. You would have no tractor and no money to replace it.
I paid cash for my tractor and will keep insurance on it for many years. For a few hundred a year to insure my tractor and attachments worth about $30K its worth it to me.