It may be just a one time deal but, more than likely there is a problem developing. It may be simply too many devices drawing on the fuse at one time or it may be a wire that is occasionally rubbing on a ground and shorting. Also may be a little mouse has gotten in somewhere and nibbled on some wire(s). Should the fuse blow again, make note of what is going on when it does blow. Do you have all the lights on and turn on one more device and the fuse blows? Are you traveling over bumpy ground where the tractor is bouncing some. Those type of things will be helpful if you note, the next time it happens for getting an idea what the cause is.
Ron