Minnesota Public Radio: As rains have gotten heavier, Minnesota farmers in recent years have been expanding a 150-year-old drainage system, pulling billions of gallons more water off soggy land and letting the state's corn and soybean fields thrive. They have laid thousands of additional miles of water-absorbing plastic tubes underneath their fields and, as a result, they have pushed upward the number of bushels per acre of the crops that dominate Minnesota's agricultural landscape. They have held their own and even flourished...