Briarwood's response was a good one and one I would recommend following. I will add a few generalized details for those interested. I used to be an adjuster and am still in the business. Now for the disclaimer - all companies and all adjusters are different. I am not your adjuster and I am not working for your companies. These are simply guidelines for how, in my opinion, your claim should be handled if you have one.
Virtually all of you have what is known as an HO-3 policy if you own a home. The exceptions are the large national carriers like State Farm and Allstate, etc, although their policies often read substantially the same in many cases. I am not sure in this instance. There are basically two versions of the HO-3 in play right now, the 1991 edition and the 2000 edition. Most are still using 1991. Some might also have a 1998 version. If you have a version previous to 2000, look at the top of the second column on page three, it reads that motorizd land convenyences are covered if they are not subject to registration, and they are used to service your residence. This assumes you do not use the tractor in any way or at any time for any business purpose. It does not say that it has to be on your premises in order to be covered, just that it is used to service your residence. Your tractor is considered personal property, which means it is covered for the 16 named perils located on pages 8 and 9. If it is damaged by any of these these things, you should be covered. If you would like it to be covered on an all risk basis instead of just the named perils, you need to schedule the tractor on a special floater attached to your homeowners policy.
I mentioned the 2000 edition above. There is a significant change that affects your tractor, and it is done with one word. It states that the motorized land conveyence must be used SOLELY to service your property. In other words, if you ever use your tractor to mow the neighbor's yard while he's on vacation, or push back his snowbanks in the winter, you are forever precluded from coverage under your homeowners policy for that tractor. One word makes a big difference in coverage on the new policy.
This is just a basic generalized overview on how the coverages should work. Remember, if you ever use your tractor to make money, it is a business purpose and you are likely out of luck for coverage on a homeowner's policy. Finally, I am not an attorney and this is not legal advice. It is simply a generally accepted interpretation of the homeowner's policy based on my previous experience. Your mileage may vary.
Every situation is different and open to interpretation by those parties involved, and this discussion should and would have no bearing on a particluar claims scenario. I am not authorized, nor do I intend to be authorized to interpret any particular scenario on anyone's behalf. Sorry for all the disclaimer, but it's a litigious world we live in, and this is not an interpretation of your particular policy. Hope this wasn't too wordy and helps clear some confusion.