Layering Soil-Residual Herbicides in Soybean

Applying soil-residual herbicides with non-residual, foliar-applied herbicides can help reduce additional weed emergence following application and, therefore, reduce the need for another application later.  The “lateness” of this year’s soybean crop undoubtedly will decrease the number of acres where layered residuals are applied, but nonetheless keep in mind that labels for most soil-residual herbicides used in foliar applications include soybean growth stages or time intervals beyond which applications cannot be made.  Additionally, these labels include time intervals for rotational crops, such as wheat.  A partial listing of soil-residual herbicides sometimes applied postemergence in soybean is presented in Table 1.  Be sure to consult the label of any product used to determine maximum crop growth stage and rotational crop intervals.

Table 1.  Maximum soybean growth stage and wheat rotation interval for several soil-residual herbicides that can be applied postemergence in soybean.

Product                        Maximum soybean growth stage          Wheat rotational interval

Anthem Maxx                Apply through third trifoliolate                1 month at up to 3.25 ounces

Dual Magnum                At least 90 days before harvest             4.5 months

FirstRate                       Prior to R2                                              4 months

Outlook                         Fifth trifoliolate                                       4 months

Prefix                            At least 90 days before harvest             4.5 months

Warrant                        Before soybean reach R2                       4 months

Warrant Ultra                Before soybean reach R2                       4 months

Zidua SC                       Sixth trifoliolate                                      1 month at up to 3.25 fluid ounces