Want to harvest an extra 2-5 bushels of soybeans per acre next fall?
You can do that just by picking the right varieties, says Ed Oplinger, a University of Wisconsin extension soybean specialist.
"If growers used reliable, unbiased yield-test data to select their soybean varieties, I believe state-average yields could be increased anywhere from 2 to 5 bu an acre," Oplinger states.
Even at today's prices, yield increases like that would add several dollars/acre to your income.
"We too often make decisions based on loyalty to companies and neighbors or just plain misinformation used to sell seed," Oplinger adds.
A wealth of information is available from independent variety trials, points out Lanny Ashlock, University of Arkansas extension soybean specialist. Even company data, like side-by-side yield results, can be useful, he says. But knowing how to prioritize and evaluate the information is the key to selecting top performers.
"If I were choosing soybean varieties, I'd look first at the maturity group best adapted to my farm. Then I'd go directly to yield," says Dale Hicks, University of Minnesota extension agronomist.
Ashlock agrees. "If a variety isn't capable of producing top yields on your farm, it probably shouldn't even be considered an option, unless there are special situations."
But sometimes all the varieties that finish in the top third of a trial yield about the same, says Oplinger.
"The problem is, there's still too much of that seed in the lower two-thirds of the trials being sold," he asserts.
Experts suggest that the best way to predict how a variety will perform this year is to look at last year's information from at least three locations. One of those locations could be your farm, but be sure to temper your findings with data from other tests in the same general maturity area.
"If you're making your decision solely from variety trials you conducted on your farm, you may be hurting yourself, especially if you're just looking at data from one year," Oplinger believes.
He says the probability of one variety yielding better than another based on one-year, one-location test results is 20%. But if that same variety tops trials at three locations over two years, the probability of it being the top yielder this year in a similar location jumps to 70%.
After establishing that a variety is likely to be a high yielder, Ashlock suggests isolating yield data from soils and field conditions similar to those where you intend to plant the variety.
"While yield should always be at the top of the list, growers should also look for performance in special conditions that may exist on their farms," agrees Hicks. Those conditions can be anything that could limit performance, including phytophthora root rot, nematodes, serious weed problems and no-till on heavy soils.
"When looking at yield-trial data, also look at tillage systems," says Ashlock. "Even if soil is the same, tillage can make a big difference in the performance of a variety, since it can affect emergence and disease."
Row width and plant population aren't important when looking at the results of a yield trial, unless they varied across the trial, says Hicks.
"Most of the research I've seen shows there's no difference in ranking order among varieties at different sites, even though row width and plant population may be different between the sites. In general, the best-yielding varieties in wide rows are the best-yielding in drilled rows."
While not every grower is picking the wrong soybean varieties, Oplinger feels not enough acres are planted to the right ones.
"You need as much unbiased performance data as you can get. It's not enough to know that a certain variety topped the yield trials in 1998. What you need to know is whether it can do it again this year. To know that requires data from several years and several locations."