U.S. corn exports, which plum­meted to levels not seen in more than 40 years after the 2012 drought-reduced crop, are bound to make a comeback in the upcoming marketing year. But it’s still difficult to predict just how much overseas corn sales will rebound, according to Chad Hart, Iowa State University Ex­­tension grain market economist.

"We are already starting to see more interest in the market with the lower prices we’re seeing," Hart said last week. "I think a lot of importers were already anticipating the lower prices."

He noted that China, traditionally the top importer of U.S. soybeans, has recently started to order additional American...