NATIONAL AG WEEK: What will spring bring?

A mild winter is affecting farmland in variety of ways as farmers look toward the spring planting season.

Gentry Sorenson, an ISU Extension field agronomist based out of Algona, said dry conditions abound in northwest Iowa.

"Rainfall would not hurt during the month of March to help recharge the subsoil moisture," he said. "I'm hearing about a few field fires, and there is a concern about high winds and dry corn stalks."

The latest report from the U.S. Drought Monitor listed all of northwest Iowa as "Abnormally Dry" or in "Moderate Drought." That's better than some locations, as a large swath of over 25 counties in east central Iowa was listed as experiencing "Extreme Drought."

Without the winter's warm temperatures, Sorenson said regional drought conditions would likely be much worse.

"Runoff of moisture from field surface due to frozen soils was reduced and snow melt and rainfall were able to infiltrate the profile due to the soil not being frozen during melt and rainfall," he explained.

Subsoil moisture levels in northwest Iowa entered winter in better shape than a year prior.

ISU Extension and Outreach's fall 2023 survey of subsoil moisture in northwest Iowa indicated improved levels of subsoil moisture at 12 of the 18 locations compared to the spring 2023 sampling, and improvement at all locations compared to 2022.

Fall sampling totals at area locations included: Calumet/Sutherland, 8.11 inches; Rossie, 9.10; Sanborn, 6.75; Sibley, 6.31; and Spirit Lake, 7.55. All totals were above fall 2022 levels and all but one (Rossie) are also above spring 2023 levels.

Still, Sorenson said the region could use a drink. Spring subsoil moisture samples taken by ISU Extension will paint a better picture of regional conditions. Those results will be available mid-April.

"We would hope for some additional rainfall before planting to help recharge extra soil moisture, allowing for the soil to become fit before farmers hit the fields," he said. "Also, avoidance of a freeze event to young crops would be ideal. These are all ideal conditions for spring. When we do not have ideal conditions, adaptations are made to do the best we can."

Warm winter weather has also affected the critters that call the soil home. Insects develop based on temperatures, and repeated fluctuations can have an impact on their populations.

"Insect mortality could increase during temperature swings of below freezing to above 50 degrees Fahrenheit. Large temperature swings could be harmful to insects and injure or cause death," Sorenson said. "Insects can become active during warm weather when they are normally dormant. The activity uses up reserves and without food sources the insect could starve."

Beneficial insects can also break dormancy during warm weather to help strike a balance between harmful insects. Sorenson noted soil-dwelling insects can be affected by soil moisture more so than soil temperature.