Maybe you can't hear the tractor but that doesn't stop you from hearing cars on the racetrack well over 20 miles away. There are plenty of noises to be heard
Two summers ago I spent some time at the Grand Canyon in the middle of the night, and you could hear a pin drop a hundred miles away. It was so silent I felt like I was in a vacuum, like sound was being sucked out of me. We could hear any car in the area for miles and miles.
The insane part was when my friend looked up and noticed a vanishingly small red sliver in the sky, and the moment he said "Is that the moon?" just about every coyote in the state of Arizona lit up at once in a cacophony of lunar worship. You could hear each single coyote, each pack (similar vocalizations among group members) and even some random guy's dog joining in the fun. It was electrifying, my hair stood straight up.
