Just last week, Sen. Joni Ernst (R-Iowa) battled it out against her Democratic opponent, Theresa Greenfield, at a televised debate. Iowa voters greatly value a candidate who is familiar with local agricultural concerns, and the debate moderator took the opportunity to test the knowledge of the candidates.

Greenfield was asked about the break-even price of corn, correctly providing an answer of $3.68 per bushel. When the attention turned to the incumbent, moderators wanted to know the price of soybeans, a question that seemed to shake Ernst. She first delivered a long response about trade policy, but was pressed by one of the moderators who told her that: “You grew up on a farm, you should know this.” After hesitating for a moment, she responded saying: “Probably about $5.50.” But Ron Steele, a TV anchor in Waterloo, Iowa and one of the moderators of the debate, made it known that she was “a couple dollars off, I think, because it’s $10.05.”

After the debate, Brendan Conley, a spokesman for Ernst, came to her defense: “There were countless issues throughout the debate, as both candidates experienced, and it was clear Joni wasn’t able to hear the question well,” Conley said in a statement. “As Joni said, the breakeven price depends on each farmer and what their operations looks like. Joni is a relentless and proven fighter for our farmers which is why she has the full backing of the Iowa Farm Bureau, the Iowa Cattlemen’s Association, and the Iowa Corn Growers.”

Ernst’s knowledge about agriculture is definitely not slim. As an Iowa native, she spent 22 years in the Iowa Army National Guard and served in the Iowa State Senate from 2011 to 2014 before being elected to the U.S. Senate. Her opponent has never before held office but has worked as an urban planner and real estate developer in Iowa.

In terms of the race, Greenfield currently has a slight advantage, according to recent polls. And she has continued to dominate the fundraising battle, raising more than $28 million in the last quarter, compared to Ernst’s $7.2 million. With Election Day just nine days out, it is unclear whether the soybean question will affect the polls.