It’s not every day that lifelong Wisconsin farmers take time out during the frenetic harvest season to do pirouettes and turns in their tractors like so many John Deere Baryshnikovs. “The Hay Rake Ballet” in an alfalfa field — set to opera music in front of a rapt crowd who oohed and aahed at every lift of the rakes used to move hay into rows — was a hit of the Farm/Art DTour, a 10-day, 50-mile self-guided driving tour of large-scale art installations and “pasture performances” along the pristine, hilly back roads of rural Sauk County, Wisconsin..