RealAgriculture agronomist Peter Johnson stirred up a hornet’s nest earlier this year when he suggested Ontario cash croppers grow shorter-season soybeans so they can plant winter wheat earlier to optimize cereal yield.
In this episode of Soybean School, Ontario Ministry of Agriculture, Food and Rural Affairs’ soybean specialist Horst Bohner weighs in on the debate. To begin with, he pulls no punches on yield: “Growing a shorter-season variety of soybeans does yield significantly less than a full-season variety,” he says.
He notes that short-season varieties may compete and even out yield long-season varieties in specific scenarios, but on average the difference is two to four bushels. Bohner also points to the Ontario Soybean Trials for further evidence of long-season superiority. “This year, within a 10-day span, in some of the trials we had as much as a 10-bushel difference at maturity.”
It’s tough to give up that type of yield potential, says Bohner. “When you think about the things you can do to increase soybean yields we have a hard time coming up with a real long list… and in terms of not costing us any money, long-season varieties may be the only one” on the list.
But Bohner is not about to dismiss Johnson’s theory. He thinks it actually makes sense in a number of situations. He notes that there are roughly three million soybean acres in the province compared to one million acres of wheat. “I would say we need to concentrate first on those acres that are not intended for wheat. That’s two million acres that we really should be maxing out in terms of the growing season – early planting and longer maturing beans,” says Bohner.
What about those one million acres of wheat? “I think there is an agronomic argument to be made that you fundamentally treat those acres different. If it’s intended for wheat, you can give up a little on your soybeans.
Bohner feels that management decision really comes down to how serious growers are about their wheat. “If you take wheat seriously it’s not a bad strategy to hold soybeans back, but you are giving up yield,” he stresses.
There are also ‘big picture’ considerations, says Bohner. “From an agronomic long-term yield perspective, it’s very important to keep wheat in the rotation. Maybe more important than any cover crop you can come up with.”
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