“I’ve heard of corn seed maintaining good germination after 10 years of proper storage, but soybean seed is an entirely different matter,” says Derek Damman, a Seed Consultants Inc. dealer in Napoleon, Ohio. “The biggest factor for saved seed is the manner of storage. I’ve seen guys put small amounts in the corner of a shop or an outbuilding where temperatures fluctuate from hot to freezing. They want to get the seed out of the way in quick fashion but are ruining germination.” If soybean seed is saved, Damman urges growers to focus on germination for the next year. He suggests cold storage or a climate-controlled area, away from humidity.
“At a bare minimum, stack seed off the floor in a basement. However, if seed is treated, that’s a different story. Treatment can seep into the beans and really hammer germination,” he says.
Before planting saved seed, Damman suggests doing a simple germination test: Place 100 random seeds on a damp paper towel in the sunshine. The sprouts are easy to count and give a rough indicator of viable seed.
“Just a few minutes online and you can find simple, effective germination tests. Also, if you insist on saving seed, plant your old soybeans late to better avoid the wet and cold,” he says. “It also helps to blend them with current year seed so there isn’t as dramatic of a drop in germination.”
Factors such as seed moisture in storage, relative humidity, temperature, handling, seed cleaning equipment and variety genetics all play a part, but unless seed is held in cold storage, it deteriorates over time in most cases, and isn’t conducive to carryover from one year to the next, says Lanny Ashlock, board member with the Natural Soybean & Grain Alliance.
“Once seed reaches physiological maturity in the pod, seed quality is at its peak and doesn’t improve further. We hope to harvest as soon as it reaches 12% moisture and do everything possible to maintain current moisture content while in storage,” he adds.
Stored soybeans are a tricky business with lots of moving parts, echoes Trent Irby, Extension soybean specialist with Mississippi State University. “Genetics and variety matter. Production location also matters. Storage environment is obviously huge. It’s a ‘depends’ answer and may involve a lot of risk to seed if stored too long.”
It’s not standard practice to keep soybeans over a second year in the seed industry. Seed must go into proper storage prior to temperature fluctuations. Not many farmers save leftover seed, unless they can’t return it to the retailer and it has high value. Treated seed can only be planted, buried or burned, says Brad Doyle, president of the Arkansas Soybean Association and owner of Eagle Seed Co.
If soybean seed doesn’t sell after Aug. 1, Doyle sells it to mills at market price. He only holds on to breeder’s seed or very important lines that might be subject to flood or tornado loss.