by Jared Strong
Dry conditions in Iowa have improved since early November, but remain the worst in a decade before winter, when there is little opportunity to increase soil moisture before next year’s growing season.
Winter has the driest months and the ground is often frozen. Also, drier soil freezes more easily.
“Unless you get to a month like December of last year with the right and temperatures in the 70s, you’ll see some improvement in an anomalous event like that, but overall you won’t see much change over the winter.” State climatologist Justin Glisan said of the winter droughts.
But even with that warm December 2021, when temperatures across the state averaged about 7 degrees above normal, there was little overall improvement from the drought. The right of December 15, 2021 spawned more than 40 tornadoes and severe thunderstorms, but precipitation across the state averaged 40% below normal, according to Glisan’s weather summary for that month.
Nearly three-quarters of the state experiences some degree of drought, according to the US Drought Monitor. The worst conditions are in northwestern Iowa, where extreme and exceptional drought has spread to parts of 18 counties and where the crop yields from some fields were the worst in the state.
However, the state’s average corn yield is expected to exceed 200 bushels per acre, thanks to a wet spring and crop genetics that appear increasingly impervious to moderate drought, said Aaron Saeugling, a field agronomist at Iowa State University Extension in southwestern Iowa.
He said soil monitoring at a university research farm in southwestern Iowa revealed that the soil is the driest in 14 years and has the potential to affect crop yields next year.
“We need about 20 inches of rain,” Saeugling said recently.
About 44% of the state had adequate or excess upper soil moisture for crops when the US Department of Agriculture released its last crop progress report of the year in late November. About a third of the state’s subsoil had adequate moisture.
In that report, about 7% of northwestern Iowa’s topsoil had adequate moisture.
It’s hard to predict how current dry conditions might affect next year’s growing season, Glisan said. The National Weather Service predicts that drought is likely to persist in Iowa at least through February.
“If we don’t get into a streak of wetter months, unusually wet months leading into the spring, we can definitely see the drought intensify and expand,” he said.
But he pointed out how quickly conditions can change. In 2018, the second wettest year on record in Iowa, part of the state suffered from extreme drought for weeks.
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