The fundamentals of the current corn market are reminiscent of the ethanol-fueled price boom of the early 2000s, Iowa State University Extension agricultural economist Dermot Hayes said last week. But this year, trade is the main driver behind the rally, especially as China buys unprecedented amounts of U.S. corn.  

“The big surprise is that China has been purchasing massive quantities of corn, beans and pork. With corn and beans, they’re driving an acreage war because each market is trying to rally to protect its acres,” Hayes said on a trade webinar sponsored by the Iowa Economic Development Authority.

Corn prices have surged from below $4 per bushel last fall to over $6 per bushel,...