Across the Northern Corn Belt, the weather events of 2019 made for a delayed planting window and, in many areas, saturated soils throughout the growing season. As we look at harvest, persistently wet soils could leave many farmers waiting for the ground to freeze in order to get their crops safely out of the field.
Trying to harvest in wet conditions can lead to a variety of issues, including field compaction and rutting and wet corn. Compaction can take years to correct in order to bring your field back to its best condition. Wet corn can lead to high artificial drying costs, lower test weights and an overall hit to your anticipated bottom line.
In a perfect growing season, we can all agree that the best plan would be to allow grain to dry down to the ideal moisture in the field before winter arrives.
But perfect growing seasons are few and far between. So, would it be possible to wait until spring to harvest your corn?
Research out of Ohio shows that grain moisture declines about 1 percent for every 24 to 29 growing degree days. In a warm, dry fall with mature grain, they measured about 0.75 to 0.92 percent per day, but in a cool fall they measured about 0.32 to 0.35 percent per day. At some point in mid to late November, the temperatures become cool and the drying rate starts to become negligible. When temperatures drop to the 20s and below, corn will freeze and dry over the winter.3
Below is a chart from North Dakota State University4 that provides an estimate of corn drydown as it sits through the normal harvest window and into the spring.
As you can see, minimal drydown occurs throughout the winter months thanks to cooler temperatures. For those unable to get their corn out in the fall or early winter, it might make more sense to wait until spring when drying occurs more quickly.
We can’t look at drydown as the single consideration, however. Leaving corn to overwinter in the field comes with its own list of concerns, including:
Disease: Winter’s cold, wet conditions can make it difficult to control root, stalk and ear rots that can occur, leading to dropped ears, lower grain quality and fallen or broken stalks.
Stalk Integrity: Varieties with high stalk and root strength scores will stand better over winter. Those with lower scores should be prioritized for earlier harvest as snowfall and wet soils can lead to issues, such as fallen or broken stalks and dropped ears.
Wildlife: In some areas, foraging wildlife can be a concern and a major factor in yield loss for corn left in the field during the winter months.
Unpredictable Weather: Heavy snows, winds and other weather events can be especially detrimental to standing corn.
Crop Insurance: Be aware of crop insurance deadlines, as these may fall before your crop is scheduled to be harvested.
The chart below from the University of Wisconsin1 demonstrates the percent of yield loss of a location in Arlington, Wisc., when corn was left over winter before harvest. It is important to note that 2000 was a year with heavy snow, while 2001 had little snow cover.
Your biggest consideration should be your bottom line: Will the cost of drying this fall outweigh the revenue lost from winter crop damage?1
Once you ’ve considered all the unexpected variables, if the value of the corn lost over winter is greater than anticipated drying costs of wet-harvested corn this fall, then it makes sense to go ahead and get it out of the field. If drying and storage will cost more than anticipated losses, then waiting to harvest until spring is a viable consideration.
Even if your harvest timing is thrown off this year, you still need to develop a plan for next season. Have you considered planting conventional corn in your fields? Check out our Conventional Corn Production Guide for tips on how to achieve results growing conventional corn next year.
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