If you measure the L, W, and H and note the arrangement and type of terminals they should be able to get one that fits physically. The amp-hours and CCA are a matter of how much you want to pay.
You could also just bring in your old battery and they'll find an equivalent on the rack unless the unit for this tractor is really unusual. Measure the battery tray, too. You may be able to put a larger one in there, which never hurt anyone.