Looks to be a horse drawn lime spreader that was converted to a 3 point hitch. In the one picture with the gears you can adjust the rate of application by moving the small gear back and forth.
/ Anyone know what this antique farm equipment is?
When I saw the variable speed, seeder popped into mind. Notice the "new" greese zerts on the axel berings and speed adjustment. That thing hasn't been out of service that long.