Four ways to overcome soybean-on-soybean challenges
Concerns about high fertilizer costs and availability have many farmers changing their traditional 50-50, corn-soybean rotations in favor of planting more soybean acres this season. But planting soybeans after soybeans could bring risks of yield loss.
AgriGold Western Division Agronomy Manager Dustin Bowling offers advice to help farmers make the most of this season’s soybean opportunities. Bowling has seen firsthand the management challenges of growing beans-on-beans.
“Plant stress and diseases caused by environmental conditions can quickly multiply yield risks, especially with soybeans planted on marginal ground,” Bowling says. “Attention to management can help growers overcome these risks.”
Variety selection is first line of defense
Bowling says selecting a variety with a high level of genetic disease resistance is farmers’ first line of defense against common soybean challenges like white mold, sudden death syndrome (SDS), and soybean cyst nematode (SCN).
Look for resistant varieties, and double check when ordering your seed to see if they contain resistance to the challenges you face. “If you’re battling white mold and standability is one of your top concerns, knowing the white mold score is critical in maximizing soybean-on-soybean rotations in white mold geographies,” Bowling says.
Bowling also advises farmers to evaluate row width if they have experienced white mold in the past. “So 15-inch rows canopy more quickly and limit airflow, which can intensify the spread of white mold,” he says. “Wider rows increase airflow during flowering, limiting white mold infection.”
A high-yielding soybean harvest can remove key nutrients, including phosphorus (P) and potassium (K). “Test soil for P, K, and pH, with a primary focus on K to ensure no deficiencies exist,” Bowling says.
For example, a soybean crop would need to uptake around 300 pounds of K to produce 100 bushels per acre. “While 55% to 60% of that K is used for grain production, the remainder is utilized by the plant,” Bowling says. “In my experience, soybean plants that have adequate K levels can tolerate disease and stress at a much higher level.”
Herbicide and seed treatment considerations
Planting soybeans back-to-back raises the potential for herbicide-resistant weeds to develop and makes already-resistant weeds more difficult to tackle. Bowling says the right herbicide trait platform is critical and advises against using the same trait package in back-to-back seasons. If rotating trait platforms isn’t an option, focus on adding new modes of action into your pre-emergent application plan.
Seed treatments will be a must in 2022 to provide another layer of protection in what Bowling calls the “hostile environment” created by consecutive seasons of soybeans. “If a soybean crop was planted last year, chances are the SCN population could increase. And, if you saw SDS last season, it will likely be a bigger yield threat this year,” he says. “The same can be said about white mold. Seed treatments add another layer of protection in the top 2 inches of the soil where these issues exist.”
Bowling encourages farmers to talk to their agronomist to select seed treatments with the correct formulation. “Look for the latest and most innovative seed treatments with flexible options that promote consistent emergence and more vigorous plant health,” he says.
Finalizing 2022 decisions
Bowling urges growers to use their seed dealers as a member of the “farm team,” relying on their expertise to find the right fit for your fields. “For example, our AgriGold agronomists can help farmers optimize second-season soybean yields with advice on mitigating stresses the growing season may deliver.”