One of my great memories is of the combine races at the county fair in Colfax, I believe. They would run those combines on a course where they had to get through gates 1/3 narrower than the combine. They could do that, because the slopes are so severe, the combines can turn on their sides at crazy angles, like 40-60 degrees.
Here's a link that shows just how crazy the land out there can be, both in steepness and in scale.
http://twitizer.com/e5OU1 As Tim pointed out, that there is some productive land, and many of the farmers are quite wealthy. A 2000 acre spread, generating 80 bushels, at $6.50/bushel, is running a $1M business.