Tariffs charged by China on American soybean shipments are expected to hit Iowa farmers hard. Last year, the U.S. exported $14 billion in soybeans to China, but Beijing on Friday announced a 25-percent tariff on the crop. Iowa State University economist Chad Hart says the tariffs could cost farmers in iowa as much as $624 million. Since the trade dispute between China and the United States began in March, soybean prices have dropped around 12 percent.