A ridge of high pressure and heat dome is building in the Corn Belt this week bringing some of the hottest weather of the growing season.
Eric Snodgrass, senior science fellow, Nutrien Ag Solutions says rain will accompany this system but the moisture won’t be enough to offset the heat.
“So, this heat that’s coming in it’s got humidity with it and that’s what’s going to be the challenge you’re going to get very high heat index value some places approaching maybe a hundred and 110 degrees or above. But it’s really that the northward extent of the very warm nights that I’m concerned about,” he says.
Record Nighttime Temperatures Stress Corn
And Snodgrass says it’s not the day time but the nighttime temperatures that could be the most stressful for corn at pollination.
“We’re looking at the middle and end of this week possibly setting some record overnight low temperatures in the upper Midwest. When you keep the humidity in the atmosphere, you prevent the temperature from cooling off at night. And what ends up happening is you keep those stressful night lows around. And so it’s just not ideal,” he explains.
Snodgrass says there’s also evidence the record hot overnight temperatures the last 45 days have already taken a toll on corn.
Heat waves starting in early June caused rapid growth syndrome in key states in the Corn Belt and now many areas are well past their historical averages for growing degree days.
“The greatest of the heat was really starting in eastern Iowa through Illinois, Wisconsin into Indiana, Kentucky, Ohio, and Pennsylvania, where many of the climate reporting districts in that region I just described have had some of their warmest overnight low temperatures. When you look at the last 45 days on the whole. Some of their warmest overnight low temperatures since records began back in the late 1800s.”
Corn Pollination Already Impacted by Heat
Snodgrass thinks that’s contributing to the production issues that are starting to emerge, including pollination problems with overly tight tassel wrap in corn.
Plus, disease pressure is showing up earlier than normal in both corn and soybeans in states that saw early planting such as Iowa and Illinois.
All of these production problems have the potential to cut yield.
“And I think we’re starting to see that showing up as more scouting happens over the coming weeks and maybe a month and a half.” he adds.
He expects crop conditions to deteriorate this week and the weather outlook stays the same through August when soybeans hit their peak reproductive phase.
“I think persistence in the pattern is going to win the day over trying to see some sort of pattern shift when we get into August. I think the next time we see a significant pattern shift, it will be on our hurricane season gets going.”
