Out on the sand plains about 50 miles north of Minneapolis, there's a cluster of broken-down farmsteads that belong to the University of Minnesota. It's flat, unremarkable land, dotted with clusters of oak and pine, crossed by weedy, dead-end roads. Near a tin shed by the side of one of the trails, three circles of bare earth have been carved neatly into the stubbled grass. Each is divided into a grid of 6-by-6 plots that will soon be seeded with various sets of prairie plants--purple bush clover, butterfly weed, green... More >>>