CHICAGO, July 12 — Biodiesel produced from soybeans produces more usable energy and reduces greenhouse gases more than corn-based ethanol, making it more deserving of subsidies, according to a study being published this month in The Proceedings of the National Academy of Sciences. The study, done by researchers at the University of Minnesota and at St. Olaf College in Northfield, Minn., points to the environmental benefits of the biodiesel over ethanol made from corn, stating that ethanol provides 25 percent more energy a gallon than is required for its production, while soybean biodiesel generates 93 percent more energy. The study’s...