“Anything you put on the land affects the chemistry and biology of the land, and that’s a powerful pesticide,” Iowa farmer Dennis Von Arb said. http://www.nytimes.com/2013/09/20/business/misgivings-about-how-a-weed-killer-affects-the-soil.html?ref=us   His neighbor grows “traited,” or biotech, corn and soy on some 1,500 acres and estimates that his yield would fall by 20 percent if he switched to conventional […]