Recent yield contests in some states show that a handful of farmers are coming close to routinely raising 100-bu.-or-better soybeans in consecutive years. If these farmers can find a way to achieve ultra-high soybeans yields year-in and year-out, you can, too.
Many farmers in the central Corn Belt have the potential to raise ultra-high-yielding soybeans without irrigation, says Vince Davis, University of Illinois (U of I) Extension soybean specialist. “For most of our soils in Illinois, we seldom see water as the limiting factor for yields, with the possible exception of August rainfall,” he points out. “We don’t know yet what the greatest limiting factor is here, but we do know that soybeans need to be healthy all season long to achieve top yields.”
Keeping soybeans healthy throughout the growing season isn’t an easy task, however. “Basically, it takes a total management approach with an emphasis on stress reduction,” says Davis. “You need to take a lot of different things into account.”
To increase your chances to attain ultra-high soybean yields, Davis provides the following top-seven tip list:
1. Choose the right varieties. Excluding overall management skills, ultimately variety selection is the most important factor that will determine soybean yields, says Davis. “In addition to choosing varieties with ultra-high yield potential, you’ll need to match the right agronomic traits with the disease and insect problems that are most likely for your particular fields,” he says. “In Illinois, you especially need to select a soybean variety that will offer resistance to the right types of soybean cyst nematodes (SCN).”
2. Consider soil fertility. “It’s easy to forget about the nutritional requirements for soybean plants, because we tend to fertilize every other year for corn,” says Davis. “That approach is okay as long as the fertility and pH levels are in an appropriate range – so regularly test soils to make sure.”
3. Plant on time. “Over the last couple years, planting delays in Illinois have been significant and can be related to yield reductions,” says Davis. “In most years, Illinois growers can maximize their season-long yield potential by planting between the last week of April and May 10.”
Planting in early April also carries a yield-reduction risk, points out Davis. However, “in years when planting isn’t finished by May 15, we see a ⅓-½-bu./acre yield loss for every day soybeans are delayed during late May and June,” he says. “Also, for farmers with poorly draining soils, soybeans don’t like ‘wet feet,’ so tiling can be helpful to ensure early planting for consistently higher yields.”
4. Start with a clean field. “Early season weed control is another essential component to high-yielding soybeans,” says Davis. “You don’t want to lose any yields to weeds, so it’s important to start with a clean field. That can rarely be accomplished if you rely solely on a postemergence herbicide application strategy. Using an initial pre-emergent, residual herbicide also helps to provide a greater window for a later postemergent application.”
5. Maximize light interception. “To achieve high yields, having less than 30-in. rows is beneficial,” says Davis. “Also, the best seeding rate to maximize yields is one that results in 100,000 harvested-plants/acre. For increased profitability, optimize planting equipment and seedbed conditions so the seeds planted per acre are not excessively more than needed to achieve that final stand.”
6. Consider an inoculant and/or seed treatment. Inoculants and fungicide seed treatments don’t typically add a lot of yield, says Davis. Yet, “for some areas of Illinois that are growing more corn in their rotations, and where planting dates occur earlier or seeding rates decrease, Bradyrhizobia inoculants and seed treatments can be a good form of insurance to achieve appropriate stands and to maximize early season plant growth,” he adds.
7. Scout often. “To prevent soybean yield loss to insects or diseases, you should really scout frequently and take notes as you scout,” advises Davis. “Remember that it will take more than one year to learn how to produce ultra-high soybean yields. Scouting helps you to react quickly to pest problems during the season; taking notes helps you to plan ahead for next year’s pest problems and variety selection.”
Lately, the main soybean disease problems in Illinois in addition to SCN have been sudden death syndrome, white mold, brown stem rot and frogeye leaf spot, notes Davis. The insects most likely to drop yields in Illinois are soybean aphids, he adds. However, Davis also says that it’s important to monitor and prevent early season bean leaf beetle damage and early to mid-season Japanese beetle damage.
Another helpful tool for learning how to achieve top yields would be to participate in any yield contests or on-farm research programs available to you, says Davis. “Next year, the Illinois Soybean Association in conjunction with the National Soybean Research Lab and four Illinois universities (U of I, Southern Illinois University, Western Illinois University and Illinois State University) are launching a soybean yield challenge,” he says. “This will be a statewide, on-farm research network, which will allow teams of five to 10 farmers to each compare their normal farming practices with experimental practices to improve yields in side-by-side plots.”
Illinois’ new soybean yield challenge will be different than just a statewide yield contest, such as the 100-bu. soybean yield contest in Missouri, says Davis. It will also be different than just an on-farm research network, like the one in Iowa, he adds. Rather, it will be more like a combination of these two programs.
“The plan is to have Illinois farmers compete as a team for top soybean yields within the nine USDA-National Agricultural Statistics Service crop-reporting districts for Illinois,” he says. “There won’t be an overall statewide winner, just district winners.”
For more information on the soybean yield challenge in Illinois, visit the Illinois Soybean Association Web site. To learn more about Davis’ research on ultra-high-yielding soybeans in Illinois, download the PDF and scroll down to read his proceeding from the U of I Corn and Soybean Classic series.