ROCKVILLE, Md. (DTN) -- As bad weather continues to delay soybean planting in some parts of the country, some growers could be left with unused bags or bins of treated soybean seed -- and few good options for dealing with them.
"Growers need to know that if they order treated soybean seeds, those seeds are theirs," explained Kris Ehler, a sales agronomist with Ehler Bros., a family seed and crop consulting company in Illinois. "Even if they don't put them in the ground, they still own them."
While most seed companies will readily reclaim unused treated corn seed, they are less likely to allow growers to return treated beans. "Corn can last two to three years in storage and still maintain its germination rate," Ehler explained. But, thanks to their oil content, soybeans are less stable in storage.
"Soybeans will degrade much more rapidly, and it's hard to store them for even just a year and have confidence that you will get good germination," Ehler said. In fact, an Iowa State study found that soybean seed germination rates dropped below 20% after 16 months in a warehouse with no climate control.
Because treated soybean seeds generally contain some combination of pesticides, usually a fungicide and insecticide, growers cannot send them into the commodity stream for food, feed, oil processing or export. Nor can they discard them casually; they have to follow federal and state regulations on the disposal of treated seed.
Growers should still check first with their seed dealer to see if their treated beans can be returned. If not, it's time to evaluate their other options, which boil down to storing, burying, planting or destroying the treated soybeans. Each comes with a host of challenges and considerations.
STORING TREATED SOYBEANS
When attempting to store treated soybeans, cool and dry conditions are best -- and if both are not possible, dryness is the most important factor, said Susan Goggi, a seed scientist with Iowa State University.
Back in 2013, Goggi conducted a study to evaluate how well treated and untreated soybeans handled storage. She collected samples of commercially available soybean varieties with a range of maturity groups and protein and oil content. She treated the seed with insecticide or a mixture of insecticide and fungicide and left some untreated.
The good news was that treated soybeans handled storage better over the course of 20 months than the untreated soybeans, Goggi recalled. The bad news is that both treated and untreated beans required near-ideal storage conditions -- a controlled climate of 50 degrees Fahrenheit and 50% relative humidity -- and high starting quality of the beans to maintain their viability.
Under those conditions, treated soybeans' germination rates only dropped from their starting range of 95% to 98% to just 92% after 20 months. In a warm, but dry storage unit -- 77 degrees and 30% relative humidity -- germination rates of treated seed dropped to 89%. But when the soybean seed was kept in a warehouse with no climate control, germination rates dropped to 80% in 12 months and fell quickly below 20% by 16 months.
Keep in mind that growers storing seed in 2019 would likely see much lower germination rates than this study produced, due to the lower starting quality of the soybean seed out there, cautioned Ohio State University Extension plant pathologist Anne Dorrance.
"The issue is that a lot of soybean seed from 2018 was really poor quality," she said. "We had reports from all my counterparts across the Midwest seeing high levels of Phomopsis and Diaporthe infections in soybean seed." Seed with 80% to 85% germination rates was not uncommon this spring. See the DTN story here: https://www.dtnpf.com/…
Nonetheless, if you have a significant amount of unused treated soybean seed, you could possibly recapture some of its value by storing it for the spring of 2020, rather than take a complete loss on it, Ehler said.
"You would need to find the most consistent environment you can, such as an insulated or air-conditioned shed," he advised. "In February, pull samples, get a germination test and find out what you've got." Even germination rates as low as 75% could be blended with higher-quality soybean seed of the same maturity group next year, he noted. At germination rates below 50%, the seed is probably no longer worth your time and resources to plant, Goggi said.
You could also do the math and see if it is worth renting some space in a storage facility with controlled temperature and humidity, Goggi and Ehler added. "You'll have to calculate -- if my germination drops to this level, I will have to bump my seeding rate to this level, and will cost me that much money versus what it costs for this controlled environment," Ehler explained.
If your treated seed is stored in bins, Goggi recommends sampling from the middle of the bin, not the top. "Skim the top part of the seed off and take a sample from deeper in the bin -- where there is going to be less fluctuation in temperature and relative humidity -- and use that to determine germination," she said. Using the same logic, sample germination rates from both outside bags and inner bags when evaluating the viability of seed stored in a large pile of paper bags, she added.
PLANT, BURY OR BURN
When storage isn't an option, what's left? First, check the label of your treated seed. Seed treatment active ingredients may come with a host of specific restrictions on disposal. Your state pesticide regulators might have their own rules, too. You can find their contacts here: https://aapco.org/…. Then consider the following:
-- Plant it: Small quantities of leftover treated seed can be planted, at proper seeding depths, into "fallow or other non-cropped areas of the farm," according to the Pesticide Environmental Stewardship (PES), an industry- and university-led group that gives guidance on legal and safe pesticide management. Increasing soybean seeding rates to accommodate for late planting and lower germination rates could also help use up excess soybean seed, Ehler noted.
-- Make it a cover crop: In 2013, USDA's Risk Management Agency agreed to allow farmers with prevented soybean planting claims to use their bags and bins of leftover soybean seed as a cover crop -- and the agency could do something similar this year. But, in the meantime, consult your crop insurance agent before you make any attempt to plant leftover soybeans as a cover, Dorrance urged.
-- Bury it: Seed burial is an option, but only if it is allowed by the label, and growers avoid burying it near water sources.
-- Outsource it: Some state municipal landfills can dispose of treated seed as hazardous waste. Other facilities can incinerate them, such as waste management facilities, power plants, cement kilns, ethanol plants and even some elevators. See more details on each state's hazardous waste programs here: https://www.epa.gov/….
What NOT to do: Trying to broadcast or spread the seed at a high seeding rate and then incorporate it is risky and could leave seed exposed or violate the label of certain seed treatment active ingredients, the PES warned. Composting pesticide-treated seed or burning it in a home or shop stove is also illegal and unsafe, the group added.
For more guidance on how to handle unused treated soybean seed, see:
-- The Pesticide Stewardship Alliance's guide here: https://pesticidestewardship.org/…
-- This guide from the American Seed Trade Association (ASTA): https://seed-treatment-guide.com/…
-- This fact sheet from the University of Minnesota: https://drive.google.com/…
Emily Unglesbee can be reached at Emily.firstname.lastname@example.org
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