When we grow alfalfa on one farm we plant 10 acres on the east side and then leave it for 3-4 years.  We then move it over 10 acres, ect.  This all happened in the 1960-1970's.   You could see a trail running at an angle across our farm that had the width of a wagon.  Dad figured it was from a old wagon trail from the Old West times.  He bought the farm in 1948.  I can not see the trail when I plant corn or beans, but we could see it with alfalfa.