The South Is Sweating and So Is The Corn

This Week In Ag #125

Just step outside. It’s brutal. You’ll instantly know it’s “sweating season” across the South and much of the Midwest. Sure, temperatures are hot, consistently now in the upper 90s across the Delta. But it’s the humidity that instantly gets your attention and triggers sweat glands overload. The dew point – aka “the misery index” – indicates the temperature where dew forms: the higher the dew point, the more moisture is in the air. The National Weather Service defines dew points above 75 degrees as “oppressive.” That’s where we’ve consistently been across the Delta; most days reaching the upper 70s.

But humans aren’t the only ones sweating it out these days. So is corn. Much like us, corn has a natural cooling mechanism where it releases moisture from its leaves. A single corn stalk can emit four cups of water each day. That’s more sweat than I release while running a 5k! Although corn loses water as it cools, this transpiration process is vital in keeping the crops healthy and productive. As water is pulled up from the roots, it is transported throughout the plant and released through tiny pores in the leaves called stomata. In addition to transporting water, nutrients are also carried and dissolved in vital tissues throughout the plant.

One acre of corn can release up to 4,000 gallons of water each day. People in areas with high concentrations of corn can actually feel it, as those local heat indexes will rise due to the humidity produced by cornfields. Corn and soybean fields across the Corn Belt serve as a giant oxygen-producing, carbon-inhaling machine. Under the summer sun, and aided by crop nutrients and irrigation, there’s an amazing amount of photosynthesis going on from Ohio to Nebraska. Satellite images reveal fluorescence levels from the Corn Belt are currently 40% greater than those of the Amazon rainforest.