Dee was correct, that is a combine! Originally there was the "reaper" which cut and bundled the grain on the stalk. I spent many hours behind the reaper, standing the grain bundles up, and placing them in tent shaped "shocks", so they would dry thoroughly, and shed water if necessary.
Then the bundles were hauled to the barn, and were sent through the "thresher", where the grain was separated from the straw, with the grain usually being blown into a bin.
As time went on and brains went to work, somebody..perhaps Gleaner Co. figured, "let us build a machine which
combines both the reaper and the thresher". Shazam! Here comes the
COMBINE !
The "field chopper" as it is called around here, is a different machine. It is used to harvest hay or corn crops. While the combine separates grain from the stalk..the chopper chops the crop with very sharp blades, in simple terms, a more 'violent' action.
Although both the combine and chopper today are generally multi row and appear much alike, the chopper's throw is much faster, so the most notable difference for the tyro, is the shape of the discharge chute. Since the chopper is discharging much faster and with much more force.. the chopper has a more gently curved discharge chute.
Note the one in the posted picture, the combine chute turns at a right angle to drop the grain.
Below, see a simple, single row chopper, set up with a corn head. I use a simple model for easier explanation...note how gently the chute is curved...much more speed and force. Actually the grain from a combine falls from the chute into the truck or wagon.
https://www.mecum.com/lots/GA0418-322594/john-deere-model-12-forage-harvester/