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Terry Aukes says leveling out his yield potential risks is a no-brainer with planting blended soybean seed varieties. He’s seen the strategy work just as well in the heavily manured areas of northwest Iowa and Minnesota as it does in the prairie pothole, wet, disease-prone areas of South Dakota. "You can't have a one size (variety) fits all mentality and get the most out of the soybean varieties you choose," he says. "Meet in the middle."
This example Pioneer IMPACT trial plot of 40 to 50 similar maturity varieties tests consistently on a range of environments in an area, testing close maturity groups together. Each plot makes 40-50 variety comparisons across various environments. Yield differential can be sizeable within maturities.
Terry Aukes knows his soybean seed. He evaluates soybean seed both personally as a farmer and professionally as seed department manager at Farmers Elevator Cooperative, in Larchwood, Iowa. “Match your choices to your toughest areas, and extract what you can in yield," he says. There is so much germplasm available to consider, and your choice should help you maximize each field's return on investment. There is so much yield variability, even among similar maturities.”
The challenge, says Fred Below, University of Illinois crop physiology researcher, is that many farmers do not pay enough attention to soybean selection. "They pay huge attention to corn selection, but seem to think they will get the same yield with soybeans regardless of the variety or maturity they choose; that is clearly not true.” You can increase soybean yields both through variety selection and better crop management, he says.
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Below's research confirms farmers can better maximize genetic yield potential by selecting varieties that respond to increased management. Soybean yields can vary by as much as 20 bushels per acre, grown in the same location, depending on variety, according to University of Illinois Variety Testing results.
Just as with corn hybrids, proper soybean variety selection based on success in a management-intensive, high-yield potential production system is critically important, he says.
Below has compared full-season varieties in high-tech systems to more typical maturities in standard systems. He finds using a full-season variety in a high-tech system allows a longer period of vegetative growth for greater responsiveness to fertility and foliar crop protection. Of the 12 traited varieties with similar maturities from five different brands planted in 2012, yields ranged from 54.4 bushels to 66 bushels per acre in the high-tech setting. Longer maturity varieties averaged more than 3 bushels better than normal maturities.
Similarly, DuPont Pioneer uses local IMPACT (Intensively Managed Product Advancement Characterization and Training) trials to characterize varieties that will perform consistently on a range of environments in an area. Jan Jackson, IMPACT field testing lead for the northern business unit, says they test close maturity groups together; for example, a plot may contain late Group I, early and mid Group IIs. Generally, 40-50 variety comparisons are made per plot, and are placed in various environments to get a strong sense of performance against challenges.
"Yield differential can be sizeable within maturities," Jackson confirms. "If we compared only SCN-resistant varieties in a susceptible area, we might see a tight range of 5 bushels per acre difference. In areas without that susceptibility, yields from similar maturities might range by up to 10-15 bushels per acre.” Outside forces like cyst steal away yield potential, so select according to your circumstances, he says.
Aukes, the southwest-Minnesota farmer and seed-department manager, plants soybean variety blends. He planted WinField Precision Pak soybeans (PrPak) this season, a 50-50 blend of two soybean varieties of the same maturity. One variety is defensive and one is an offensive variety.
"Planting two varieties blended together addresses the variability in our fields," says Aukes. "In our cooperative's test plots, the blended seed has out-yielded each of the varieties on its own by 1-2 bushels per acre. That is quite a bit to me at current soybean prices."
Iowa State University research several years ago looked at different variety combinations blended at different percentage levels. "The premise is that two same-maturity varieties, given the unknowns of a growing season, can buffer the effects of weather and other stresses," says Eric Bartels, WinField product manager for western Iowa and southwest Minnesota. "Yields show one component is better than the other in any given area. But across the field, the synergies of the two bring up the field average to optimize all the acres."