One that comes to mind is "On the Road Again" by the great Willy Nelson. Possibly "Convoy" by C.W. McCall or maybe "She thinks my tractors' sexy" by Kenny Chesney Just a couple off the top of my head.
I remember the first season harvesting corn. I was 16 or 17 and i had a casete with Auchung Baby in side A and The Joshua Tree in side B, both great albums of U2.
When I spent some time over in the US and Canada harvesting, one of the bosses was hooked on the Wall Flowers song - One Headlight, (this is going back 6 years) we'd nearly listen to it every day on the way out to the paddock. Another popular drinking song was: "Mamma's Don't let your Babies grow up to be cutters"