Q Why do farmers just leave their corn to whither and die in the fields? Shouldn't they be harvesting it while it's still green and lush?
A Of the corn your consumers see as they drive the state’s highways, roughly 99.3 percent of it is not the sweet corn they’re familiar with from your produce section, but the “yellow dent corn” used in livestock feed, processed foods and ethanol. That distinction is important because unlike sweet corn, which is harvested while the corn stalk is still green and the corn is immature and juicy, yellow corn is harvested only after the kernel has dried and hardened to a starchy stage. What appears to the average consumer as dead standing cornstalks in the field are actually considered mature, harvest-ready stalks by the farmer.
Yellow corn actually reaches that physiologically mature stage weeks before harvest begins. However, because much of the billions of bushels of corn American farmers grow is stored for months to years before it’s sold or used, it usually must be dried in order to prevent spoiling while in storage. Corn can be reliably stored at about 15 percent moisture without suffering quality losses. Corn standing in the field in mid to late September is typically about 35 percent moisture. So, farmers must dry that corn before storing it.
They have generally one of two ways to do that drying: One, they can use grain dryers that are in effect huge fans that heat air using propane and blow it through the grain one large batch at a time, drying the corn much as a blow dryer dries your hair. Or, they can let Mother Nature dry it for them—depending on weather conditions—by leaving it standing in the field for several weeks to months after it reaches maturity.
Typically, farmers use some combination of those two methods to dry corn before storage, and, as with many farming practices, it’s often a delicate balancing act that’s refined through years of experience and much research. Naturally, it’s in the farmer’s best interest to leave the corn standing in the field as long as possible, to take advantage of the natural drying and save on costly propane. However, it can be a huge gamble that risks an entire year’s crop. As the corn kernels are drying, so is the stalk that holds those ears of corn. As they dry, they become brittle. That brittleness brings the potential for valuable ears to fall to the ground, where they can no longer be practically picked up by today’s modern harvesting equipment, and thus go to waste. Fall and early winter winds also pose a risk to a standing field of corn, as does sudden rain and snow that prevents the heavy equipment from being able to get into the field.
So, farmers use a number of tools to help even out the demands for drying time, including different seed varieties that dry at different rates, different marketing tools that allow differing levels of moisture, and different combinations of artificial drying, natural drying and storage options—all based on the anticipated weather conditions for the season. Hitting the “sweet spot” is a good example of how, despite all its science, profitable farming remains an art form, as well.