Forget that image of pretty pastoral farmhouses dotting the rural U.S. landscape: The reality is that farms are responsible for an ever-increasing amount of pollution that poses a significant threat to rivers, the ocean, and wildlife. A recent study by the Pew Oceans Commission found that fertilizer runoff and livestock feedlots were among the fastest growing sources of ocean pollution, even though many of the largest farms are concentrated in states thousands of miles away from the nearest ocean. (One of the worst offending states is Iowa, which has no national parks or forests, but plenty of mega-farms.) Concern about pollution from farming has added extra fuel to the debate over the farm bill, a 10-year, $171 billion package that includes proposals to reduce water pollution, protect wetlands, encourage farmers to practice conservation, and limit the verrry generous subsidies that mega-farms currently enjoy.