Good Weed Control Starts in the Fall
November 16, 2022 | By Colin Rogers, Sustainable Systems Agronomist
When considering no-till farming, one of the largest challenges, and a frequently debated topic, is weed control. Some tillage practices may reduce weed seed banks by burying seed deep within the profile where the seeds then struggle to establish. Deep tillage practices such as moldboard plowing can contribute to weed management, but plowing also has many additional costs including fuel, labor, and soil erosion.
Minimum tillage practices, such as vertical tillage, have risen in popularity as a great tool to manage the previous year's crop residue, as well as create a more mellow planting profile for better seed to soil contact when planting cash crops. However, this shallow, more ideal planting profile is also a more ideal seedbed for weed seed germination. Recent studies have found that there is no statistical difference in weed seed germination rates between minimum tillage and no-till systems.1 Instead of burying weed seeds deep in the soil profile or creating a rough aggregated surface with poor soil contact, minimal tillage tends to bury weed seeds between 1-2”, improving overall seedling emergence. These findings imply that there is a need for another tool to reduce weed emergence while still being good stewards of our land. When partnered with an effective preemergent herbicide program, both weed density and biomass can be lower in no-till systems compared to stand along conventional tillage systems 2
Good Weed Control Starts in the Fall
Both no-till and minimum-till practices can be more prone to winter annual, biennial, and perennial weeds establishing and becoming a larger problem in the following spring. Some of the more economically damaging species growers find in fields are marestail, kochia, and thistles. Herbicides and cover crops can reduce weed densities in fields if managed properly.
- For a more successful and cost-effective fall burndown in a corn/soy rotation consider using one quart of 2,4 D Ester with glyphosate.
- If glyphosate resistant marestail populations are suspected in a corn/soy rotation, combining glyphosate with 2,4 D and Autumn™ Super 51 WDG herbicide can provide control along with lasting residual control of future fall emerging weeds.
- For fall wheat burndowns Dicamba can be used with a short planting restriction depending on product use rate and geography.
A dense stand of cover crop can reduce fall weed establishment, and suppress spring weed growth, which may give growers an extended window in which to make spring herbicide applications. Achieving a dense stand may require earlier seeding through aerial applicators or high clearance machinery. The more biomass that is created, the greater the suppression of weeds.
Good Cover Crops to Consider for Weed Supression:
- Cereal rye ahead of soybeans
- A winter killed grass (oats), and a winter hardy legume (vetch or clover) ahead of corn
Remember the success of next season’s crop starts at harvest, however no matter where you are on your regenerative agriculture journey, ForGround by Bayer is here to help your operation every step of the way. ForGround is a farmer-first digital platform that can help transform the way farms of all sizes make the transition to sustainable agricultural practices. This program offers growers tools, resources, and discounts, as well as the potential to earn revenue through the Bayer Carbon Program* for the adoption of regenerative practices and gives farmers the opportunity to connect with businesses looking to advance their sustainability and carbon goals.
*This Bayer Carbon Program described in this material is subject to the current version of the Bayer Carbon-Smart Practices Master Agreement. The information is to aid in the understanding of the Bayer Carbon Program and does not change or modify the Bayer Carbon-Smart Practices Master Agreement in any way. The recommendations in this material should be considered as one reference point and should not be substituted for the professional opinion of agronomists, entomologists or other relevant experts evaluating specific conditions in a given field.
ALWAYS READ AND FOLLOW PESTICIDE LABEL DIRECTIONS. Performance may vary, from location to location and from year to year, as local growing, soil and weather conditions may vary. Growers should evaluate data from multiple locations and years whenever possible and should consider the impacts of these conditions on the grower’s fields.
Not all products are registered for use in all states and may be subject to use restrictions. The distribution, sale, or use of an unregistered pesticide is a violation of federal and/or state law and is strictly prohibited. Check with your local dealer or representative for the product registration status in your state. Autumn™, Bayer and Bayer Cross are trademarks of Bayer Group. For additional product information call toll-free 1-866-99-BAYER (1-866-992-2937) or visit our website at www.BayerCropScience.us. Bayer CropScience LP, 800 North Lindbergh Boulevard, St. Louis, MO 63167. ©2022 Bayer Group. All rights reserved.
1 Auskalniene, Ona & Kadžienė, Gražina & Janusauskaite, Daiva & Suproniene, Skaidre. (2018). Changes in weed seed bank and flora as affected by soil tillage systems. Zemdirbyste-Agriculture. 105. 221-226. 10.13080/z-a.2018.105.028.
2 Blaise, Desouza & Wanjari, R. & Singh, Rakesh & Hati, Kuntal. (2015). The response of weed community in soybean with conventional and conservation tillage systems on rainfed Vertisols. Archives of Agronomy and Soil Science. 61. 1289-1301. 10.1080/03650340.2014.993389.
3 Farmer, Jaime A., et al. "Influence of tillage method on management of Amaranthus species in soybean." Weed Technology 31.1 (2017): 10-20.
4 Fonteyne, Simon & Singh, Ravi & Govaerts, Bram & Verhulst, Nele. (2020). Rotation, Mulch and Zero Tillage Reduce Weeds in a Long-Term Conservation Agriculture Trial. Agronomy. 10. 962. 10.3390/agronomy10070962.