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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.
Yield differences vary by field
Bartels says yield differences farmers may see planting PrPaks vary by field, as verified by WinField's Nationwide Answer Plot program, but he notes farmers with the most highly variable conditions will see the biggest bang for the buck. "That's where we see the greatest value, although every year and every field is different," he says. "This unique strategy can help you maintain yields on tough acres and capitalize on the highest potential on better areas."
Fred Below is testing four PrPak blend varieties this season for yield. His work is part of his "Six Secrets of Soybean Success" multiyear research effort to help farmers get more yield by identifying better management strategies. He places variety selection third in priority order of the six factors, but says he could easily move the factor to No. 2 with closer attention to fertility needs in conjunction with variety selection.
"We know variety selection is most important when combined with fertility and row spacing," he says. "In the nearly 12-bushel-per-acre swing across varieties of similar maturities in six Illinois high-technology plots last year, fertility produced the most yield difference across locations. The high-tech system mitigates other factors, although the drought may have limited the yield swing in 2012."
He encourages farmers to improve soil fertility through balanced crop nutrition and fertilizer placement technologies to get the most out of the full-season varieties chosen.
"Soil fertility is the most overlooked component of soybean management for high yield," says Below. “Phosphorus, in particular, can be immobilized in soil and might not be available in sufficient quantities for modern soybeans. High-yield potential management systems (70 to 80 bushels per acre) remove as much phosphorus from the soil as does 150-bushel corn. Our work with corn has shown that spring placement of phosphorus in a band 4-6 inches beneath the row improves early plant growth and vigor. We anticipate a similar response for soybeans."
Other newer technologies – such as biological seed treatments that establish favorable relationships between the soybean plant and microorganisms – could also be a management strategy for enhancing uptake of critical nutrients like phosphorus and nitrogen. Below recommends complete seed treatments, particularly for farmers who plant early in the season. Fungicide, insecticide and nematicide treatments added an average 2.6 bushels per acre to yield in 2012.