After a wet, cool spring caused the slowest planting pace in 40 years, Iowa farmers need “Goldilocks” weather for the remainder of the growing season to produce decent corn and soybean crops this year.
“With such a late start, everything has to be just right the rest of the way for our 2019 crops to be good,” says Dennis Todey, director of the USDA Midwest Climate Hub, based at Iowa State University in Ames. “We need temperatures to be near to above normal, but not too hot. And it can’t be below normal.”
Much of Iowa’s corn and soybeans in 2019 were planted two and three weeks later than normal, and cooler-than-normal temperatures in May and June delayed emergence and development even further. “It wasn’t a storybook start,” he notes.
Weather for rest of growing season
Not too warm, not too cool, not too wet, not too dry. “That’s the kind of weather needed the rest of this growing season,” Todey says. “Some crops, especially in northern Iowa, are at risk of not reaching full maturity even with average growing degree day accumulation.”
For example, a 100-day corn hybrid planted May 25 in Floyd County isn’t expected to reach black layer (mature stage) until early November, more than two weeks after the average date of the first fall frost for that area. Farmers can keep track of growing degree days for their fields with the Mesonet weather calculator.
The National Weather Service forecast for the first-half July is for above-normal temperatures, which will help crop development. But that weather pattern isn’t expected to stay. “It looks like we are going to move back into a cooler, wetter pattern,” Todey says. “That’s pleasant for people and for livestock, but not for corn.”
Wet grain in fall
Cooler weather means fewer growing degree days for corn and soybean crops to mature. “The late planting date leads to concerns in the fall because of the need to extend the growing season to allow crops to mature. Additional drying of grain will likely be necessary,” according to a USDA report by Todey.
Farmers should plan for a longer, wetter fall. “Get propane for grain drying lined up now,” he advises. “It’s too soon to predict when the first freeze could hit. My biggest concern is not that corn won’t make it to maturity. I think most corn will make it to maturity. Unfortunately, we will have some wet corn and probably muddy field conditions.”
He adds, “A perfect Goldilocks scenario — average temperatures midsummer and additional warmth from August on and a delayed first freeze — would benefit crops in Iowa this year.”
New record for wettest 12 months
Iowa recorded its wettest 12-month period on record with 50.73 inches of precipitation since June 2018. That’s about 16 inches above the 30-year average. Conditions turned somewhat drier in June 2019, which put Iowa in better shape for crop progress than other neighboring states.
Iowa crops are faring better than those in Illinois, Indiana and Ohio, where precipitation has been upward of 140% of normal this year. In Michigan and Ohio, less than 70% of the corn was emerged as of June 23.
Iowa and Nebraska are generally behind in crop progress due to late planting, but not as far behind as Illinois, Indiana and Ohio. Eastern Corn Belt areas have had an incredibly wet spring and are way behind normal. Soybean emergence there at end of June was only in the 40% range. The eastern Corn Belt will have a very late crop this fall, and a lot of their acres didn’t get planted.
“Prevented planting acres are going to impact U.S. production this year as we move through the rest of the growing season,” Todey says.