Soybean School: Burndowns, water volume, and controlling volunteer corn

Don’t skip that burndown. That’s Rob Miller’s number one recommendation for soybean growers as a cold, wet spring pushes into May.

Miller, BASF’s technical development manager, notes 2018 post-harvest conditions prevented many growers from controlling weeds in corn fields last fall and the yield-robbers are lurking beneath corn residue, waiting to compete with the 2019 soybean crop.

“We’re seeing a lot of winter annuals and perennial weeds and they’re fairly large,” says Miller. On this episode of RealAgriculture’s Soybean School, he stresses the importance of hitting last year’s corn fields with a burndown, “especially if you’re not growing one of the new herbicide-tolerant traits because once the soybeans are up it’s extremely difficult to control some of those problem weeds like glyphosate-resistant Canada fleabane.”

Miller notes that regardless of your herbicide choice, spray water volume will play a huge part this spring in weed control success. “Higher water volumes are critical. Coverage is key, especially on some of these larger weeds.” Volume will become even more important if poor weather persists and weeds grow larger as sprayers continue to be parked in farmyards, says Miller who recommends a minimum application rate of 20 gallons per acre.

Miller also discusses the practicality of a two-pass weed control program given current weather conditions. That includes a soil-applied herbicide upfront followed by a second application in-crop to clean up misses and future escapes. (Story continues after the video.)

Miller expects volunteer corn to prove challenging in soybean fields this year. He notes that many Ontario growers changed their combine settings last fall to deal with gibberella ear rot in corn and unprecedented DON levels. That’s left a lot of intact corn sitting in fields waiting to germinate. He offers tips on how to best control volunteers in soybeans, including split herbicide applications that focus on annual and perennial weeds during early spring and then target volunteer corn after planting or early post-emerge.

Click here for more Soybean School episodes.

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