Unless you are in business and using it for that purpose, your tractor and implements should be covered under your homeowner's policy against theft under the contents coverage of your HO policy.
However, there may be some fine print involved. For instance, my agent says that it should be kept in my barn when not in use. The barn should be locked (just like your house) at all times so that there will be evidence of forced entry if someone breaks in and steals it. Absent evidence of forced entry, it is questionable if the insurance company will pay for the loss.
Also, check with your agent to make sure you have REPLACEMENT COST COVERAGE on your contents. That way, if something is stolen, the company has to pay the cost to buy a brand new tractor of the same type rather than knocking off for depreciation because of age.
The funny thing, the increased coverage (replacement cost) does not really cost that much more. Check with the agent who sells you your homeowners policy to make sure you have all of the bases covered. Also photographs of the contents your barn or garage (as well as your house)are helpful since if someone cleans you out, you may not remember every single tool that you had until you go to look for something two months after you have cashed the claim check.
Remember, there has to be evidence of forced entry or the insurance company does not pay. Make sure the cops get that down in the report if you do have a breakin so the insurance company cannot weasel out of paying. A broken window, jimmied door, destroyed lock, etc. are evidence of forced entry. If the crook picks your lock you might have a problem. Again, discuss your options carefully with your insurance agent to get the best possible advice and read your policy to make sure you actually have what the agent says he sold you.