Barb Boustead moved to Nebraska 20 years ago. She quickly learned about “corn sweat.” What does that mean? It refers to the late-summer spike in humidity from corn plants cooling themselves. It’s “something that locals very much know about,” she says.
God created human bodies to sweat as a way to cool off. When sweat evaporates from your skin, it lowers the surface temperature of your body. He gave some plants similar abilities. In plants, the process is called transpiration. Roots take in water from soil and bring it up to the stem. The water exits the plant through tiny holes or pores. It comes out as water vapor. When the plant releases the water into the air, it cools itself a little. It can also remove some heat from the air around it.
Most of the time, humans don’t notice the effects of plant sweat. But water from transpiration makes up about 10 percent of the moisture in the atmosphere. Plant sweat is so important that NASA launched a mission at the International Space Station in 2018 to study it.
One acre of corn can sweat out up to 4,000 gallons of water every day. Nebraska grew almost 10 million acres of corn last year. That’s a lot of sweat!
In Nebraska, corn does most of its sweating in July. Soybeans produce a lot of moisture in August. So the state stays pretty humid all summer.
Even if temperatures don’t actually get hotter, rising humidity can make the air feel warmer. That’s because people’s sweat doesn’t evaporate quickly if the air is already soaked with moisture. People feel sticky and hot.
The humidity problem will probably stick around. Farmers across the United States plant more acres of corn every year. That’s partly due to a growing demand for ethanol. This fuel can be made from corn.
More than a third of corn grown in the United States is turned into fuel. Cars and some planes guzzle it. The tradeoff for more fuel might be more humidity in places like Nebraska. But locals in the “Cornhusker State” know that sticky summers come with the territory.
You cause the grass to grow for the livestock and plants for man to cultivate, that he may bring forth food from the Earth. — Psalm 104:14
