By Jared Strong
A streak of warm and dry weather has created ideal conditions for some Iowa farmers to start planting their corn crop this week.
“It has been an absolute flurry of activity,” said Meaghan Anderson, an Iowa State University Extension field agronomist who monitors central Iowa.
Monday was the earliest planting date for corn this year for farmers to be eligible for federal crop insurance replanting payments.
It was also the earliest eligible planting date for soybeans in southern counties in the state. The rest of the state’s soybean planting can begin Saturday. That’s earlier than in previous years — a recognition of farmers’ successes planting earlier and of the state’s expanding growing season due to a warming climate.
Temperatures across the state have been higher than normal for about a week and on Wednesday were exceptionally warm. Sioux City’s high temperature of 92 degrees set a new record for that day, said Jeff Zogg, of the National Weather Service.
“The normal high is 60 there in Sioux City, so you’re talking 32 degrees above normal or average for this time of the year,” he said.
Other areas were very warm but not did not reach unprecedented temperatures, such as Des Moines, where the high of 84 degrees was three shy of the record.
Topsoil temperatures everywhere in Iowa this week exceeded 50 degrees — a key threshold for corn seed germination — but they were projected by Iowa State to dip back below that threshold by Sunday. A cold front is likely to afflict the state this weekend with chances of rain and snow.
The current heat wave is considerably different than conditions at the start of planting season last year, when rains and cold temperatures delayed farmers for weeks. It was the 12th-coldest April on record, and only about the first 10% of the state’s corn crop was planted that month, according to the U.S. Department of Agriculture.
Drought conditions that hampered yields in some parts of the state last year have diminished substantially in recent months, but they are still slightly worse than they were a year ago, according to the U.S. Drought Monitor.
Virtually all of northwest Iowa is suffering from some sort of drought, and a sizeable area near Sioux City has “exceptional” drought — the worst classification.
“I would assume we are sitting in a worse spot this year than we were at the beginning of last year,” said Leah Ten Napel, an Extension field agronomist who monitors that area.
The National Weather Service predicts that drought conditions in western Iowa will improve in the coming months.
Ten Napel said there is a lot of field work ongoing in northwest Iowa this week with some planting.
“People will get started quite a bit more next week would be my guess,” she said. “Holding off for this week isn’t a bad thing.”
Corn yields have typically been highest if farmers plant seed during a roughly four-week time period from mid-April to mid-May, according to data collected by Iowa State. Even though planting was delayed last year and the growing season was haunted by drought, the state still averaged yields of about 200 bushels per acre. The record, set in 2021, was 204 bushels per acre.
This past March was drier than normal in all parts of the state except for southeast Iowa, according to the Iowa Department of Agriculture and Land Stewardship, but about 78% of topsoil across the state has adequate or surplus moisture.
“We just have really incredible soil conditions,” said Anderson, in central Iowa. “Things are dry, at least dry enough to be able to get in and really do some nice preparation on the soil. But there’s moisture still below so that those folks who are planting are getting that seed into some nice moisture.”