PMN Crop News Homepage   

Posted 27 May 2014. PMN Crop News.

Tillage Plays a Big Role in Managing Herbicide-Resistant Weeds, Says Researcher

Source: United Soybean Board Press Release.

Chesterfield, Missouri (May 14, 2014)--Deep-till or no-till – which method is better for managing weeds? According to Purdue University Associate Professor Bryan Young, Ph. D., there are pros and cons to both tillage methods for the purposes of weed control.


Traditional deep-till methods bury weed seeds, making it harder for them to germinate, but they also prolong the seed’s viability. On the other hand, no-till methods leave seeds in the upper inch of soil where they are likely to germinate the following year, but those seeds are also more likely to be removed by predation.

In a recent “Focus on Soybean” webcast , Young discussed the differences between managing weed emergence in deep-till and no-till environments.

• Deep-till — Most would assume this practice is preferred because if the weed seeds are buried deep, many can’t germinate. However, when seeds are buried deeper, seed predation is more difficult, and the seeds’ longevity increases. This creates the possibility that those seeds could germinate in future years. “In a deep-tilled environment, you may be removing about 80 percent of the weed seeds from the germination zone, which alleviates some of the pressure for the following year, but might increase the weed seed longevity in the soil in the following years,” says Young.

• No-till — No-till isn’t for everyone, but it can work for farmers who have effective herbicide modes of action in place to deal with weeds in the near future. In these environments, weed seeds remain in the upper inch of soil, where they can germinate more easily. However, predation is higher because the weed seeds are at the surface where birds, insects and mice can eat or remove them. With no-till practices, farmers know that they will have to manage those weeds the following year. If they are prepared to do so and have effective herbicide modes of action as viable options, that may be the best tactic rather than prolonging the seed’s life with deep-till.

The soy checkoff provides farmers with resources they need to develop a diversified weed-management plan, including tillage, herbicides and other practices, to help lower the risk of developing herbicide-resistant weeds. Visit to learn more.

“Focus on Soybean” webcasts are sponsored by the soy checkoff through a partnership with the Plant Management Network. All U.S. soybean farmers have access to this full presentation for free until June 30, while a shorter executive-summary version of the presentation is always available.