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What do we know about the value of preemergence herbicides in soybean?

By Ryan Miller and Lisa Behnken

Earlier this spring we shared a couple videos on the lessons we have learned from corn herbicide research at Rochester, MN.  Now we would like to share what we have learned about the value of preemergence herbicides in soybean.  See or video Soybean Preemergence Herbicides: Always Have One Down

We are back in the research plots in Rochester, checking-in to see what we have been learning with our soybean herbicide research plots.  During the past couple of weeks, we shared information on the “reach-back” potential of several preemergence corn herbicide products.  In our soybean plots, we experienced similar weather conditions with a lack of rainfall after the applications of preemergence herbicides.  With that lack of rainfall, the herbicides were slow to activate and we saw an initial flush of weeds emerge, but unlike some of our corn herbicides the soybean preemergence products did not exhibit “reach-back”.  Not to worry, the preemergence herbicides have now activated and are “reaching forward”.  We see that the herbicides are now helping to control future flushes of small seeded broadleaves and grasses, reducing the overall weed pressure.  In addition, they have widened the window of postemergence herbicide application.  Without a pre down we needed our post emergence herbicide applications to go on four days after soybean emergence, with pre’s down we had several weeks to get the post applications on.  We will be following this trial during the 2017 growing season and providing periodic video updates.

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