Several storm systems moved through last week and brought needed rain to significant areas of Iowa. “Unfortunately, we also saw severe weather and flooding from some of the storms,” notes Mike Naig, Iowa ag secretary. In general, crops continue to be in very good condition, with 84% of the state’s corn and 80% of soybeans rated good-to-excellent, according to USDA’s latest weekly survey.

Heavy rains that marched across a large part of central and north-central Iowa on June 14, coupled with recent storm systems across other parts of the state resulted in significant areas of ponding as well as hail injury. Flooded fields take several days for the water to recede to fully evaluate how much crop area is destroyed.

Corn underwater
Corn may be able to survive under water for one to four days, depending on crop stage and air temperature, says Mark Licht, Iowa State University Extension agronomist. “And even if the crop does survive, saturated soil conditions will undoubtedly stall root growth and hinder nutrient uptake and plant growth,” he says. “At this stage of the growing season, it is unlikely that replanting drowned-out areas will be a viable option. However, when water recedes and field conditions are fit, it would be worthwhile to plant a cover crop to protect the soil and compete against weed growth.”

ISU’s Integrated Crop Management newsletter has more information on survival of corn that’s been underwater. See Corn Survival in Flooded or Saturated Fields. ISU Extension publications Hail on Corn and Hail on Soybean have information on management options and yield impacts from hail injury.

The complete weekly Iowa Crop Progress and Weather Report is available on the Iowa Department of Ag & Land Stewardship’s website iowaagriculture.gov or on USDA’s site nass.usda.gov/ia. The report summary follows.

Crop report
Above-normal temperatures were felt throughout Iowa with severe storms hampering fieldwork and causing localized damage during the week ending June 17, reports USDA’s National Ag Statistics Service. Statewide there were 4.7 days suitable for fieldwork. Activities for the week included harvesting hay, delivering grain, replanting storm damaged fields and applying postemergent herbicides.

Topsoil moisture for Iowa is rated 4% very short, 15% short, 72% adequate and 9% surplus. Subsoil moisture rated 5% very short, 16% short, 71% adequate and 8% surplus. While rain fell over much of the state, in south-central Iowa the percentage of the area that rates very short for both topsoil and subsoil moisture increased over the previous week.

Iowa soybeans 80% good-to-excellent
With virtually the entire corn crop emerged, 84% was rated in good-to-excellent condition as of June 17. Iowa’s soybean crop was 97% emerged, two weeks ahead of average. The state’s soybean crop is rated 80% in good-to-excellent condition. Iowa’s oat crop is 64% headed, two days ahead of average. And 83% of the oat crop is good-to-excellent.

Hay condition improved to 73% good-to-excellent. Pasture conditions are rated 64% good-to-excellent. Scorching temperatures and high humidity continued to stress livestock.

Weather summary
According to Justin Glisan, IDALS climatologist, the week that ended June 17 saw hail, flooding and high winds in parts of Iowa. A wet start to the week greeted central Iowa as widespread thunderstorms moved through during morning hours of June 11.

Storms advanced through western Iowa, producing measurable rain. Later that afternoon and evening, a line of severe supercell thunderstorms moved from western Iowa and quickly weakened as they spread across the state. Three semis were blown over and multiple farm buildings were damaged near Thurman, in Fremont County in southwest Iowa.

Southeast Iowa also received measurable rain, though still well-below normal. On June 12, isolated thunderstorms, some severe, moved through north central and northwest Iowa, ahead of a cold front. High pressure moved into the state on June 13, bringing calm conditions. In the early morning hours of June 14, widespread thunderstorms broke out across the middle of Iowa, along a warm front. A portion of the state between Sheldon and Ames experienced flash flooding from slow moving storms.

Ames with 4.25 inches of rain

Ames in central Iowa had the highest one-day precipitation total for the week at 4.25 inches. There were a few reports of severe hail, including two inches in Webster County. Much of eastern and southeast Iowa also received afternoon rainfall from the same system.

Ottumwa in southeast Iowa reported 1.77 inches from two lines of storms. Northwest Iowa saw spotty thunderstorms over the weekend; a few reports of severe winds in western Iowa were received on June 17.

Little Sioux hit 99 degrees

Temperature-wise, the week began 6 to 8 degrees above normal in southern Iowa. Lamoni reached 91 degrees on June 11 and Shenandoah reported 94 degrees on June 12. Midweek saw statewide temperatures averaging in the mid-80s, six degrees above normal. A heatwave ended the week with average highs in the mid-90s, 10 to 14 degrees above average. Heat indices were in the low triple digits, as dew point temperatures pushed into the 70s. Little Sioux in northwest Iowa observed the highest temperature of 99 degrees on June 17.