Heat-Ravaged Crop Showing Signs of Stress

High temps take toll, especially on late-planted corn

The persistent, blistering heat wave across the corn belt has had a double-edged impact on crops.

“We really gained a lot of heat units from the heat streak in July which will mature the crop but hurt yields,” says Brent Smith, who ended up planting 20% of his 6,000 corn acres in June due to wet spring weather. “It doesn’t look good due to the heat and no rain.”

Through mid-July, most grain farmers were hoping for a good year, despite late planting. Then rains shut off and the temperature gauge zoomed higher. Now farmers are wondering what they’ll have to sell this fall, despite good prices.

“This 90 degree weather has probably taken anywhere from 10% of the yield in the very best corn, to 35% of the yield in the June-planted corn,” says Smith, who farms near Lebanon, Ind. “It’s done pollinating, but it was pollinating all during the 90 degree weather, which is not good.”

On the bright side, late-planted corn is doing a good job playing ‘catch up.’

“Originally we were three weeks behind projecting out toward harvest, but we’ve gained back probably half of that, due to the warmer weather,” Smith says. “Depending on what August brings, we may be a week or week and a half behind normal by harvest. It may be the first of October when we start shelling corn.”

Threat of early frost

Meteorologist Elwynn Taylor, Iowa State University, says La Nina is to blame for this year’s weather extremes. He also says it could bring an early frost to the corn belt. Some late planted crops may be at risk this year.

To determine if your crop is safe, start counting growing degree days from the day your corn crop is silking. Then look 50 days ahead on your calendar and mark that day. That is when that field will typically be safe from frost, he says.

“The crop probably won’t be mature until 60 days after silking,” he adds.



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