Here in Iowa, they don't spook out of the area at all. Provided they have some timber to go to. They will retire to the closest bedding areas and just wait until the combine leaves. I have ground hunted fencerows of cornfields that were being combined. It actually worked well. The deer stayed down while the combine was working so I got set up without spooking them. Then I swear, 10 minutes after the farmer left, they came out and started feeding on the leftover corn. Around here fresh cut corn or soybean fields are considered "HOT" spots for deer.