You can pull start the tractor, as others have said. You really should figure out why it isn't starting on its own. I don't know the specification for L2000 glow plugs, but for other machines I have the resistance is under 2 ohms. Set your meter to 20 ohms, disconnect the linking bar or wire between plugs, and connect one probe to the tip of a glow plug, and the other to its base. Repeat for all of them, and see what you get.
If you pull start it, do it very slowly. You can mechanically overspeed the engine, and potentially cause damage. The fact that you are getting smoke implies you have fuel, but perhaps ensuring the injectors are all getting fuel would be wise.