KDSN RADIO News
Annual Survey Shows Northwest Iowa Moisture Near Record Lows
Iowa State University Extension and Outreach is reporting subsoil moisture is well below average throughout northwest Iowa. Gentry Sorenson is a field agronomist in Northwest Iowa. He says this year’s numbers are some of the lowest on record dating back to the 1970s.
"This go-round we really kind of eye-opening. Subsoil moisture has not been this low since that time period. That crop was really drawing upon that subsoil moisture all year trying to do the best it could," said Sorenson.
Soil moisture is measured at the same locations in the spring and fall with samples weighed wet, dried for 48 hours, and weighed dry. The study map includes Sac, Ida, and Monona counties.
"Pertinent to you guys as well in Crawford County because it would give you kind of an estimate at least of where you're at. Just kind of looking at the rainfall that's happened and looking at the drought monitor on top of it," said Sorenson.
Sorenson says rainfall is the best way to replenish subsoil moisture in any region. Rainfall is below average as well with much of northwest Iowa in a drought this summer which intensified in late September, according to the Iowa drought monitor. He says the spring thaw in March and April could help with three to five inches typically falling in those months.
"The problem with snow is the ground is frozen at that time and even in the very early days of the spring it's still frozen so what we're looking for is rainfall to happen before the crops are planted," said Sorenson.
ISU Extension says 80 percent of that rainfall will contribute to subsoil moisture reserves while corn and soybeans usually need about 20 inches of rainfall and subsoil moisture to produce a crop.