Journal Star: Corn farmers could see growing pressure from the companies that buy their golden kernels to adopt sustainable practices, according to a new report that warns of price swings, risk of groundwater depletion and nitrogen runoff contributing to the Gulf of Mexicos dead zone. U.S. farmers produced almost 14 billion bushels of corn in 2013 worth $67 billion. The annual harvest is essential to a wide variety of industries and products from sweeteners and plastics to meat and ethanol. But there are threats...