Grace Smith | August 12, 2022

Corn sweat, a term referred to as plants giving off water through evapotranspiration, is increasing moisture in Midwest air, which is harming crops. The humidity in the air can increase temperatures between five and 15 degrees Fahrenheit over corn fields during mid-July and August.  

Iowa harvested over 13.1 million acres of corn and produced 2.58 billion bushels in 2019. One acre of corn can give off up to 4,000 gallons of water per day, contributing to extreme humidity, or, corn sweat. 

Midwest humidity isn’t just caused by corn sweat. Climate change has pushed the global surface temperature in 2022 to become the sixth hottest June in 143 years, being 1.57 degrees Fahrenheit above the 20th-century average. In addition, humidity is accounting for warmer nights because the extra moisture makes it more challenging for temperatures to shift higher or lower.

This corn sweat and increased temperatures from climate change create a possible breeding area for pathogens and pests near growing plants and grain, according to the 2018 National Climate Assessment. Bacteria can cause crops to fail and pests can impact crop growth by feeding on plant roots when humidity increases. 

The climate assessment also said increased humidity and precipitation contribute to soil erosion potential and reduces planting workdays because of waterlogged soil.