When the guy finished the field, I noticed some tarping from the engine back to the seat. I guess it got cold enough, finally.

Seems to me, in our area, leaving residue in the field is wasteful! Usually those guys would remove corn stalks by harvesting with a forage harvester. Of course, the stalks are usually a bit greener, and the cob is still on it, but still... And it would be unheard of to leave wheat or barley straw in the field. Most in this area like to process the straw by having cattle and hogs mix their byproducts with it. Of course, that means trips through the field to gather the residue, and more trips to spread it back out!