The Trump administration’s plan to impose steep tariffs on imported steel and aluminum raised strong concerns from farm organizations last week. The ag groups worry that the tariffs could spark retaliation and cause a slump in exports of soybeans, corn and other crops.

The big concern is retaliation from China, the largest customer of U.S. soybeans, accounting for $14 billion in sales and more than one-third of total U.S. soybean production.

“Prior to today’s announcement, China has indicated that it may retaliate against U.S. soybean...