Iowa corn lucky to be ‘knee high by the Fourth of July’ this year

Most years, Iowa corn is far taller than “knee high by the Fourth of July,” but this year’s crop — set back by late planting and too little rain — fits the adage.

“This year it’s more of an appropriate saying,” said Mark Licht, an assistant professor and cropping systems specialist with Iowa State University Extension and Outreach. “I was just in a couple of cornfields that were at knee height. A couple of other fields I’ve driven past, I question whether they were even at that level.”

The “knee high” phrase may be as old as Iowa, founded in 1846.

One of the earliest time the phrase appeared in an Eastern Iowa newspaper was on July 3, 1884, when the Sumner Gazette said “It has been considered that if corn was knee high by the Fourth of July that the crop will be sure and safe,” The Gazette’s Time Machine reported last year.

But with advanced corn breeding and fertilizer, corn today often reaches 8 feet by midsummer. But that’s under good growing conditions, the Iowa Corn Growers Association reported.

Iowa’s cold, wet spring delayed corn planting statewide by two weeks and set soybean planting back 12 days, the Iowa Department of Agriculture and Land Stewardship reported in May.

That wait contributed to 4 percent fewer corn acres planted nationwide this year, according to numbers released Thursday by the U.S. Department of Agriculture’s National Agricultural Statistics Service.

The service estimates nearly 90 million acres of corn were planted nationwide this spring, down 4 percent from 2021. Farmers planted 88.3 million acres of soybeans, up 1 percent from last year.

The data comes from surveys of 9,100 segments of land and more than 64,000 farm operators during the first two weeks of June.

“Part of the issue with corn growth is areas where we had too much water, so we had some saturated soil that slowed things down a little bit,” Licht said. “In areas of the state that are really dry, that is holding back some of that height as well.”

He said corn and soybeans plants are not elongating as much as they normally would by early July, which is typical of hotter, dryer conditions.

About half Iowa’s 99 counties are abnormally dry or worse, with two Western Iowa counties — Plymouth and Woodbury — considered in extreme drought, according to the U.S. Drought Monitor’s June 30 report.

But there’s still plenty of potential for Iowa’s 2022 corn crop.

“Other than the northwest quarter of the state, really the rest of the state has some pretty great soil moisture,” Licht said. “I’ve had about 12 inches of rain in June at my house. That’s a lot more than normal. Hopefully, we keep getting the occasional downpours.”

In Iowa — the nation’s No. 1 corn producing state — corn acres are down about 2 percent, Licht said. He sees the late planting season as less of a factor in declining corn acres in Iowa than the price of fertilizer.

The U.S. is importing less nitrogen fertilizer from Russia because of sanctions imposed after Russia’s attack on Ukraine. Supply chain issues and COVID-19 also have slowed fertilizer production, contributing to prices two to four times higher than they were in September 2020, ISU reported in June.

While the selling price of corn also has increased, some farmers may have decided to switch some corn acres to soybeans, Licht said.

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