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Beware: Corn sweat

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Illinois

* I’m sure you’re aware of the heaps of rain we’ve gotten in the past week. KHQA…

Did you know that certain crops can actually cause it to feel more humid outside?

Evapotranspiration, or “corn sweat,” is a process that occurs with mature corn and soybean crops in the summer months. July and August are the primary months. […]

Water is taken in via the roots of the mature plant and continues up the crop through the stem and leaves.

The leaves release water vapor into the atmosphere, which then raises our humidity levels. […]

According to the US Geological Survey, 1 acre of corn can add between 3,000 and 4,000 gallons of water to the atmosphere.

* The Washington Post in 2022…

The moisture from corn evapotranspiration may not only make it intolerably muggy during the day, it can also slow cooling at night, leaving little respite from the heat. Lows on Wednesday from Texas to Illinois only dipped to 75 to 80, about 5 to 15 degrees above normal. The low temperature in Des Moines was just 82, its warmest minimum temperature since July 1936.

When ingredients are in place for showers and storms, the added juice can make them more intense; this could be the case in parts of the Midwest on Wednesday where the National Weather Service has declared an elevated risk of severe storms.

Corn is not the only culprit in summer humidity, though. Soybeans also contribute substantial moisture through evapotranspiration. In other words, soybeans sweat, too. Moisture also evaporates from bodies of water and even from the wet soils of areas with recent rains. Not to mention a good deal of the moisture that reaches the Corn Belt during summer is sourced from the Gulf of Mexico and sometimes even from the Pacific Ocean.

* From the US Geological Survey…

Plant transpiration is pretty much an invisible process. Since the water is evaporating from the leaf surfaces, you don’t just go out and see the leaves “breathing”. Just because you can’t see the water doesn’t mean it is not being put into the air, though. One way to visualize transpiration is to put a plastic bag around some plant leaves. As this picture shows, transpired water will condense on the inside of the bag. During a growing season, a leaf will transpire many times more water than its own weight. An acre of corn gives off about 3,000-4,000 gallons (11,400-15,100 liters) of water each day, and a large oak tree can transpire 40,000 gallons (151,000 liters) per year.

In 2023, Illinois planted 11,200,000 acres of corn. So between 33,600,000,000-44,800,000,000 gallons of water could be added to the atmosphere each day.

* Ambrook Research…

The United States grows more corn than any other crop, which means it has an outsized effect on the agricultural industry. And while it doesn’t require as much labor as many other crops, humans are still involved in the harvest. That can be unfortunate for anyone working in those fields, given that it can feel 15 degrees hotter in a cornfield than outside it. According to professor Suat Irmak, head of agricultural and biological engineering at Penn State, if you’re working in a cornfield, “You are going to sweat a lot, and sometimes you might feel like it’s difficult to breathe because it’s so humid, so hot, and there’s a closed canopy.”

That may not have too big of an impact on a farmer driving a combine from an air-conditioned cab. But when maintenance, detasseling, hand-picking sweet corn, or other work requires spending time on the ground, that heat index difference can add up to significant — and potentially fatal — health risks for farm laborers.

That was the case for Cruz Urias Beltran, who died tragically from heat stroke while working in a Nebraska cornfield in 2018. Beltran is just one of hundreds of farmworkers who have died from heat-related issues in the U.S. over the last decade, where federal protections for farmworkers have lagged behind the rate at which growing seasons are getting hotter.

“As temperatures continue to rise, farmworkers are already working in the fields through record-breaking heat and in dangerous temperatures. This is a major factor in agriculture being one of the deadliest industries for workers in the United States today,” said Antonio De Loera-Brust, director of communications for the United Farm Workers (UFW).

posted by Isabel Miller
Wednesday, Jul 17, 24 @ 2:22 pm

Comments

That’s fascinating. I had no idea. (But then we don’t grow a lot of corn or soybeans in Chicago.)

Comment by JoanP Wednesday, Jul 17, 24 @ 2:34 pm
The house I grew up in was across the street from a corn field. I know about corn sweat and the miserable humidity of summers in rural Illinois.

I much prefer the asphalt urban heat island effect, which at least is tempered by the proximity to the lake. Once storms pass through, or sometimes even as they approach, the breeze comes off the lake and it is amazingly refreshing.

Comment by 47th Ward Wednesday, Jul 17, 24 @ 2:35 pm
Anyone who’s spent anytime detasseling corn knows the true meaning of hot/wet.

Comment by Dotnonymous x Wednesday, Jul 17, 24 @ 2:36 pm
Uh oh, I’m so screwed.

Comment by Honeybear Wednesday, Jul 17, 24 @ 2:41 pm
The local farm stand brings in several farm trailers of corn every day. They told me it is picked starting at 4AM before it gets hot outside. What they don’t sell by 2PM they take to the food stores, any remaining they take to the food bank where it helps feed hungry families.

Comment by Dupage Wednesday, Jul 17, 24 @ 2:50 pm
Keller’s Sweet Corn…. Growing up in Collinsville I think my parents had it about every other evening for dinner. It is the best I’ve had.

Comment by Club J Wednesday, Jul 17, 24 @ 3:25 pm
So Reagan was right he meant corn not trees are causing global warming/S

Comment by DuPage Saint Wednesday, Jul 17, 24 @ 3:28 pm
“I am announcing a mandatory crop bagging program to recover water, and prevent needless humidity.” — Line from fake disaster movie to be made in the future.

Comment by thisjustinagain Wednesday, Jul 17, 24 @ 4:04 pm
- Anyone who’s spent anytime detasseling corn knows the true meaning of hot/wet. -

Seconded.

Comment by Excitable Boy Wednesday, Jul 17, 24 @ 5:04 pm