Harvesting soybeans at an ideal moisture level is a challenge for farmers to achieve in any year, and 2026 is no exception.
What commonly happens is soybeans drop below a desirable moisture level in what seems like a blink of an eye, notes soybean yield champion Randy Dowdy, based in Valdosta, Ga.
“You’ve got about 30 minutes in a day when you can pick soybeans at 13% moisture,” he says, only half joking. “After that, they’re below 13% and we start to get seed quality issues. Then the test weights go down and yields go down, too.”
David Hula says overly dry soybeans are an issue for any farmer, especially those who are growing seed beans.
“You can get wrinkled seed coats, and as you handle beans, that wrinkle can cause a pinhole and then those beans are not going to germ,” explains Hula, based in Charles City, Va.
Hula and Dowdy’s solution? They use a desiccant to hasten soybean plant maturation at a higher moisture level. The practice can provide more flexibility with harvest timing.
“We go in there and knock the leaves off these soybeans at 15% to 17% moisture, and then get the combine in there and harvest them. They’re not hard to dry whatsoever, and there’s some free bushels there. No doubt about it, you’re making some more yield,” says Dowdy in this week’s Breaking Barriers With R&D podcast.
When Using A Desiccant Can Make Sense
Desiccating soybeans with some type of drying agent – often a defoliant designed for that purpose or a herbicide – is a common practice used by soybean growers in the South. There, weather conditions stay warmer longer going into the fall and offer fewer environmental triggers to mature soybeans – unlike what occurs in the upper Midwest with its cooler, shorter days in autumn.
“There are situations and seasons where soybeans tend to remain a little green and are difficult to harvest,” says Seth Naeve, University of Minnesota professor and Extension soybean specialist in an online article. “When there are warmer fall conditions where we don’t have an early or even a normal hard freeze, or if farmers had to delay planting — all could lead to harvest challenges in the North and desiccants could be of help.”
Dowdy says many farmers struggle to achieve a 60-lb. test weight with soybeans, because moisture levels can fluctuate in the field.
“The yield goes out the window when beans go wet-dry-wet-dry, it’s part of that phantom yield loss,” he explains. “If growers can get them out of the field and dry them, that’s an easy way to make some money, I think.”
Naeve adds that while Midwest growers might find a desiccant useful in some years, “they won’t be needed every year or on every acre.”
Midwest Growers Weigh The Pros And Cons
Eric Anderson, a field crops educator with Michigan State University, believes there is potential for Midwest soybean growers to benefit from using a desiccant. But Anderson notes there are potential risks and rewards that growers need to evaluate before using one.
In a recent online article, he details some pros and cons for farmers’ consideration:
Potential Benefits:
- Induce uniform seed moisture across a variable field
- Potentially control weeds depending on desiccant selected
- Quicken harvest, reducing the risk of shatter loss with wet-dry cycles
- Allow for timely winter wheat or cover crop planting
- Potentially reduce harvest difficulties associated with green stem
Potential Challenges:
- Yield loss likely if applied before yield has been set
- Need higher temperatures and humidity for efficient and quick desiccation
- Harvest may only be a few days earlier than normal to achieve desired grain moisture and to account for pre-harvest interval (depending on desiccant used)
- Cost of products and application and possible yield loss may make the practice unprofitable
- Greater shatter losses possible if not harvested at optimum time after desiccation
- Seed quality can be impacted if desiccant applied too early
Herbicides Labeled For Use And Their Cost
Anderson says the selected desiccant should have a short pre-harvest interval, so the crop can be harvested once the desired grain moisture level has been achieved. Care should also be taken to ensure the chemical applied will not negatively impact establishment of the following crop or cover crop (rotation restrictions).
Anderson references three herbicides labeled as potential harvest aids: paraquat (Gramoxone), saflufenacil (Sharpen) and sodium chlorate (Defol-5). Various adjuvants (e.g., crop oil concentrate, methylated seed oil, non-ionic surfactant) are required or recommended according to product labels, he adds.
From Dowdy’s perspective, with soybean prices below the cost of production, growers need to investigate any agronomic practice that can put more yield in the bin.
“Prices are already bad. We don’t need to give away any yield to boot; we just can’t afford it. So we’ve got to be willing to try some things,” he says.
“The herbicide costs about $2 an acre, not counting the application. So, it would be something to consider for sure,” Dowdy adds.
Farmers can learn more from the most extensive study to date conducted by the Science for Success team of soybean researchers in 2024 at 19 locations across 13 states.
In addition, Naeve is looking at the effect of desiccation from several aspects through a research project funded by the Minnesota Soybean Research and Promotion Council.
Watch the latest Breaking Barriers with R&D podcast with yield champs David Hula and Randy Dowdy on YouTube or Farm Journal TV and on AgriTalk.
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