get your serial number on tractor, quick connect battery disconnect, turn off fuel. turn the wheels and put some sort of steering wheel lock device on.
implements about all you can do is chain them up.
but above will not deal with vandalism, putting stuff in fuel tank or into the engine oil or hyd oil.
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cameras can work, but your better off with nice good lighting high outdoor lighting. and then cameras correctly placed, just putting it on the house or barn and pointing it. doesn't mean it is going to give worth while video.
DVR (digital video recorders) and camera system, can be expensive setup, getting a low budget setup or trying to get something cheap off ebay, will not hold up, been there done that.
grass, weeds trees can be a killer on DVR's with motion detection. and needing to keep things cut low, and trees cut back. needs to be kept up on.
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out of sight, out of mind, is a good statement someone else said.