Funded by the Illinois Soybean Checkoff
Soybean Success: No Longer a Secret
By Mace Thornton
A
gronomists at the University of Illinois haven’t yet cracked all the codes to the secret formula for soybean production in the Prairie State. But they are on the leading edge of the curve, thanks to their shared commitment to continuous improvement alongside the state's soybean farmers. Although yield trends are an upwardly moving target because of the breakneck speed of agronomic innovation, University of Illinois Postdoctoral Researcher Dr. Connor Sible spilled the beans during the recent Soybean Summit about what might be the optimal soybean growing strategy in Illinois for 2024. According to Sible, who works alongside noted Professor of Crop Physiology Dr. Fred Below in the Department of Crop Sciences at
18 February 2024
the U of I, the recipe to soybean yield success in Illinois requires a comprehensive and season-long approach. "The big picture is holistic,” he said. “Soybeans have a lot of potential the day they are planted, but soybeans can also be lazy. The big key is that once the plant makes it through the soil, it’s important to maintain a consistent push throughout the growing season.” Farmers pushing for optimal yields need to deploy a full-package strategy, Dr. Sible explains. That starts with fall fertility before planting, then with selecting the right planting date and caring for the plants all the way through foliage maturity. "It all ties together from a systems approach,” he said. “If you do one thing here or there, you can see little bumps, but it's when you piece it all together that
you are going to see the greatest advantage.”
Old Fertility For starters, Sible emphasizes the importance of a long-known agronomic saying, “Soybeans like old fertility.” “Soybeans really have a preference for residual nutrients from the previous year's corn crop,” he said. “In a four-year study comparing fall- and spring-applied phosphorus ahead of soybeans, we observed consistent positive phosphorus responses in the first three years, where fall treatments outperformed spring applications.” Sible said the 2023 phosphorus study showed no fertilizer-age preference, which he theorizes might have been weather-related. Sible said the “old fertility” preference is likely related to an innovative theory by Ph.D.
candidate Marcos Loman, who has suggested that fall-applied fertility stimulates the breakdown of corn stalks and residues. “This stimulation potentially aids in the mineralization of residue, benefiting soybeans in the subsequent spring,” Sible explained. “This theory proposes advantages such as improved residue breakdown, enhanced nutrient cycling and smoother planting conditions, supporting the notion that fall fertility may provide a substantial advantage for soybean cultivation in Illinois.” Planting Date In a challenge to traditional farming practices, Sible said, research is showing that earlier planting dates for soybeans can play a crucial role in increased production.
