Farmers raced to finish soybean harvest last week, trying to stay ahead of snow forecast in northern Iowa.

“We’re about 80 percent done on beans,” Jim McDermott, a  Asgrow technical agronomist in Spencer, said Oct. 24. “There’s still beans to go, but a lot got wrapped up. Last week was the week we’ve been waiting for all fall.”

Iowa farmers harvested nearly one-third of the state’s 10-milion-acre soybean crop between Oct. 15 and 22, according to the U.S....