Residual Herbicides for Soybean Weed Control 

Senior farmer in a field looking into the distance.

Make the Most of Your Post-Emergent Herbicide Application 

The business of growing soybeans seems to get harder every year. From the factors we can’t control to those we can, everything that goes into a bushel of soybeans is complicated. Not the least of which is the ever-increasing populations of resilient and resistant weeds that farmers need to manage. Tough weeds like Palmer amaranth and waterhemp have changed the way farmers approach weed control, shifting to manage proactively for prevention rather than simply to economic thresholds in order to throttle future weed populations resulting from escaped weeds.


That means being smart and getting the most of your post-emergence application. Including a residual herbicide like Zidua® SC herbicide or Outlook® herbicide with your post-emergent Liberty® herbicide or Engenia® herbicide application not only makes economic sense but provides the peace of mind that comes with knowing you’re set up for future success.


According to research from North Carolina State University, soybean farmers who used more active ingredients in their herbicide applications (3.2 vs 2.1 modes of action) had higher yields and an average of 30 percent greater economic return, even with the increased herbicide costs.1 More diverse herbicide programs reduced weed populations and seed contributions to the soil seedbank without reducing profitability.

Make Every Spray Count

With potentially tighter supply challenges across the industry this year, it’s as important as ever to be good stewards of your herbicides and get the most you can out of every spray. If you’re limited on the number of applications you can make across your field, make every trip the most effective by including a residual herbicide with your post-emergence application.


“Residual herbicides like Zidua SC herbicide and Outlook herbicide from BASF can really be an integral part of your program,” said Eric Eade, BASF product manager. “When tank-mixed with Liberty herbicide or Engenia herbicide, soybean farmers can control tough weeds like pigweed and waterhemp through canopy.” Outlook herbicide is up to 2.5 times more likely to activate than competitive products like metolachor and acetochlor2 and requires as little as a quarter inch of moisture. And Zidua SC herbicide has up to two weeks longer residual control.3


Money in Your Pocket

An extended window of control also means less likelihood of a respray application late in the season, and the additional expense that goes with it. “Including Zidua SC herbicide or Outlook herbicide in the tank during your initial post application can save you as much as $6 to $10 an acre over the cost of a respray application of Liberty herbicide should you need it later in the season,”4 according to Eade. “Adding a residual helps keep fields clean, reduces the risk of late season weeds emerging and the need for a respray application. It not only provides peace of mind, but it’s just smart from a dollars and cents standpoint.”


Without a residual herbicide, there is a greater opportunity for late season weeds to emerge and become large, impacting yield, quality and harvestability. And the number of seeds produced from weeds like waterhemp or Palmer amaranth that may have escaped is tremendous, leaving them to lie in wait in the soil for the following season. Palmer amaranth is aggressive, growing up to 2.5 inches per day and producing up to 600,000 seeds per plant.5 The additional modes of action enhance your resistance management program as well, which is paramount to clean fields and a profitable crop this season and in the future. 

Confidence in Your Weed Control 

Including a residual herbicide with your knockdown application not only gives you the best chance for effective weed control but comes with the support and confidence of your BASF team. When you apply Liberty herbicide or Engenia herbicide according to label instructions and follow the guidelines below, we guarantee commercially acceptable weed control.


Liberty Herbicide S.T.O.P. Application Guidelines:6

  • S: Start with a clean field prior to planting.
  • T: Target weeds smaller than three inches at the time of application.
  • O: Optimize coverage.
  • P: Pair with residuals.


Engenia Herbicide Application Guidelines:7 Apply to existing weeds up to four inches tall and always include a pH buffering adjuvant such as AEGOS™ or Sentris™ Buffering Technology.

  • Use adequate tillage or a BASF burndown herbicide.
  • Pre-plant or pre-emerge:

        o      Option 1: Zidua PRO herbicide.

        o   Option 2: Zidua herbicide plus another site of action herbicide such as Sharpen® or Verdict® herbicide.

  • Post-emerge:

        o   Apply Engenia herbicide plus Outlook herbicide or Zidua herbicide.


Make the most of every trip across the field by including a residual like Zidua SC herbicide or Outlook herbicide with your post-emergent Liberty herbicide or Engenia herbicide application. A smart approach to weed management that adds value to your bottom line, as well as your peace of mind.  

1 Challenges with Herbicide Resistance and Value of Cultural Practices in Managing weeds: Examples from Research in North Carolina. NC State Extension Publications. March 25, 2020.

2 Comparisons available on

3 BASF Trials.

4 Assumptive calculations based on BASF proprietary market data.

5 Palmer amaranth management in Soybeans. United Soybean Board. 2013.

6 Liberty Herbicide Weed Control Guarantee Program.

7 Engenia Herbicide Weed Control Guarantee Program.


Always read and follow label directions. Engenia Herbicide is a US EPA Restricted Use Pesticide. A pH buffering adjuvant, like AEGOS™ or Sentris™ Buffering Technology, is required in every application of Engenia herbicide. Engenia®, Liberty®, Outlook®, Sharpen®, Verdict® and Zidua® are registered trademarks of BASF.


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