Soybean School: The trouble with tillage for weed control

Tillage can play an important role in weed control but integrating additional tools always makes for a better strategy, says BASF agronomist Rob Miller.

On this episode of RealAgriculture Soybean School, Miller illustrates this point when he takes a close look at a wheat field from 2023 that received a fall burndown and some light tillage to finish out the year.

Miller says the view from the field’s edge is pretty good, but as he begins his field scout it doesn’t take long to find a cluster of sow thistle that survived the tillage and could be a troublesome challenge for IP soybeans or a dry bean crop.

Digging up these weeds, Miller notes that the small sow thistles have rhizomes that are developing quickly, two to three inches below the ground. “When you come in here early in the year with a high-speed disc it just starts to multiply the issues,” he says. “It will take one plant and turn it into two or three.” (Story continues after the video.)

Until there’s more growth, it’s difficult for tillage or a burndown herbicide to control these weeds.”It just tends to clip it,” says Miller. “It’s really tough to penetrate and get that into the roots until we start to get a little later into the season and get a bit more green growth.”

If IP soybeans emerge before those weeds are controlled, they can be a challenge to take out, says Miller. In the video, he shares control options for herbicide tolerant soybeans, including increasing glyphosate rates and adding a second mode of action to the spray tank.

“You’re not going to eliminate it all just in one year. It’s going to be a three- to five-year process, ” says Miller. He recommends growers get out and scout, know the weeds in their fields, and don’t rely only on tillage as an effective means of weed control.

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