(Spencer)– Substantial rain is still needed in most areas of northwest Iowa to bring subsoil moisture levels back to where they should be following extremely dry conditions last summer and fall.
Paul Kassel, a field agronomist with the Iowa State University Extension Service, says typical soils in northwest Iowa have the potential to hold from 10 to 11 inches of moisture in the top five feet. He says soil moisture readings from near Spirit Lake, Rossie and Pocahontas had only 1.4 to 5.0 inches of plant available moisture last fall. Kassel says the sites gained an average of four inches of subsoil moisture over the winter and spring. Even then, he says the sites near Pocahontas and Spirit Lake are still below normal, with subsoil moisture ranging from 5.7 to 7.2 inches of available plant moisture. Kassel says most of that is in the top three feet of the soil profile.
Kassel says if spring rainfall isn’t enough to replenish the moisture reserves that crops will be more dependent on rainfall this summer. Corn and soybean crops require about 22 inches of soil moisture to produce a normal crop. As a result, he says summer rainfall, which is about 18 inches for May to mid-September, will be needed to produce a normal sized corn and soybean crop.
Rain chances are in the forecast the latter part of this week and into the upcoming weekend.
