Reducing the number of weeds in the soil weed seed bank as early as possible in the growing season can lessen the competition the crop seeds face during emergence. Starting with a ‘clean’ weed seed bank and staying clean throughout the year can help save farmers time and money. If fields experience less weed pressure, the need for in-season ‘rescue’ passes is not as high. One way to start fields ‘clean’ is to implement pre-emergent herbicides.
Beck’s Practical Farm Research (PFR)® data shows the importance of using pre-emerge herbicides with multiple effective SOAs to lay the foundation for a successful herbicide program. The question is whether the pre-emerge herbicide will last until canopy closure.
Once the crop reaches canopy closure, the limited light makes it difficult for new flushes of weeds to emerge. A pre-emerge herbicide is like a blanket, a blanket that reduces new flushes of weeds. As the pre-emerge herbicide begins to break, the blanket develops holes, allowing new flushes of weeds. We typically see pre-emerge herbicides break roughly four weeks after application. Therefore, achieving canopy closure prior to the pre-emerge breaking aids in weed suppression.
Many post-emergence herbicides do not provide residual activity, and although they may control emerged weeds, these herbicides will not protect against future weed flushes. This means in-season residual applications are key for season-long weed control.
In a year like 2020, many pre-emerge herbicides broke before canopy closure because of the slow soybean growth, making the use of an in-season residual crucial. When using a Group 15 in-season residual such as Warrant®, Beck’s PFR team saw up to an 8%, 7%, and 4% increase in waterhemp control when Warrant was applied after utilizing a one, two, and three “effective” SOAs pre-emerge herbicide, respectively.
Less response to in-season residuals has been noted when three “effective” SOAs are used over one or two SOAs. In heavier weed pressure, in-season residuals are still recommended for extra protection, even if you utilize three “effective” SOAs in your pre-emerge herbicide. Group 15 premixes, such as Warrant® Ultra and Prefix®, contain a Group 15, as well as fomesafen, a Group 14 herbicide. Group 15 herbicides do not have post-emergence activity, but the addition of a Group 14, such as fomesafen, will help increase post-emergence control of glyphosate-resistant (GR) waterhemp.
Some waterhemp populations have been documented to be resistant to Group 14 post-emergence herbicides such as fomesafen, Cobra®, etc. Weed management takes a full-season approach that utilizes an effective pre-emerge herbicide, effective post-emergence trip, and in-season residuals. No matter which trait platform you select, we must reduce the number of late-season escapes, in return reducing the soil seed bank.
Utilizing a pre-emerge herbicide with multiple effective SOAs lays the foundation to a successful herbicide program. Most post-emergence herbicides do not have any residual activity, making an in-season residual application key for season-long weed control. Reduce the amount of late-season escapes to reduce the soil seed bank, setting up success for years to come.
While weed control continues to provide new challenges with each growing season, you have the option to bring the power to your soybean platform. For more information on recommended herbicide programs and options for soybeans, contact your local Beck’s representative or check out Beck’s 2021 Recommended Soybean Herbicide Programs guide.
Innovation has always been at the heart of farming. Dreaming, inventing, and experimenting with new tools, equipment, and products is what allows farmers to continue improving their operations. Beck’s family of employees thrives on innovation too, which is why they developed the Practical Farm Research (PFR)® program. Today, Beck’s provides a truly comprehensive, innovative, and practical agronomic research program that helps farmers with decisions that can improve profitability. By evaluating hundreds of new management practices and inputs, we deliver unbiased agronomic data to help farmers make better decisions and increase profitability.
Beck’s is the largest family-owned retail seed company in the United States that serves farmers in Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Mississippi, Missouri, Ohio, South Dakota, Tennessee, and Wisconsin. According to a recent seed industry survey, Beck’s ranks as the third largest corn and soybean brand in the United States. At their core, all Beck’s employees are Farmers at Heart. It stands for something special. It has soul. It has truth. And it represents a community of farmers, employees, and dealers who strive each day to seek challenges, push boundaries and innovate. Beck’s has, and always will be, proud to serve a community of farmers who love what they do and who are proud to be… Farmers at Heart. For more agronomic new and information, visit Beck’s Agronomy Talk page or blog at BecksHybrids.com.