When it comes to increasing soybean yield, University of Illinois plant physiology professor Fred Below has two words of advice — plant early.
In his presentation earlier this month at the Ontario Agricultural Conference, Below shared data from eight years of trials that show growers in Illinois lose almost half a bushel (0.47 bu/ac) for every day planting is delayed after April 23. On this episode of RealAgriculture’s Soybean School, he shares how this data and a growing understanding of soybean vigour and resilience is convincing many Illinois growers to plant soybeans before corn.
“We are starting to realize that corn yield is all about uniform emergence,” says Below. “Soybean yield comes from getting the canopy closed as quickly as your can… that means you intercept more sunlight and one of the ways to do that is to plant early.”
Unlike corn, soybeans don’t require even emergence, says Below. He adds that late-emerging soybeans don’t impact the crop like late-emerging corn, which acts like weeds and compete against their more vigorous neighbours. “The soybean plant makes its yield in August. We’re seeing that it makes a lot of sense to wait for when conditions are right for corn, but if you’re itching to go, put the soybeans in first.” (Story continues after the video.)
Below notes that planting early also allows the plant to produce “another node or two and that node gives us a huge potential for more pods.” He does admit that early planting does increase the risk of frost damage, but he emphasizes that the crop has the ability to bounce back thanks to axillary buds in the cotyledon. “As long as those cotyledons have some green to them that means there’s an axillary bud that the plant can regrow from,” he says.
In the video, he shares how soybeans he planted on April 3, 2021 survived a hard frost 17 days later and went on to be the highest-yielding performers in his trials.
However, Below does not deny the impact weather can have on soybean planting. He says it makes sense for growers to keep one eye on the weather, but if the soil is fit and there’s no impending cool, wet weather — get them in the ground.
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