Blowing fuses are caused by excessive current, often a short circuit, sometimes a motor or solenoid that is defective. I don't know that tractor at all, but I can give you some general guidelines for tracking it down.
See if you can disconnect the power lead right at the load (whatever is being powered by that fuse). If you can, now test the circuit for excessive current. You can either use a fuse, if you have plenty, or, use a test light across the fuse slot. If there is no current flowing, it should not light. If it doesn't light, the problem is in the load you just disconnected. If it lights, there is current flowing and you have a short somewhere in your wiring.
If there is a switch somewhere, disconnect the power side of the switch, and repeat as above. If the light still lights, your problem is between the switch and the fuse. If the light no longer lights, disconnect the downstream (load) side of the switch, reconnect the switch, and try again. If it blows now, your switch is the culprit. If it does not, the problem is between the switch and the load.
See the idea? Split the circuit up, and test each part. That will start to narrow down where the problem is.
