2021
Comparison of Non-Chemical Control Methods as Part of an Integrated Weed Management Strategy in Soybean
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Contributor/Checkoff:
North Central Soybean Research Program
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Kevin Bradley, University of Missouri
Co-Principal Investigators:
Project Code:
71278
Contributing Organization (Checkoff):
North Central Soybean Research Program
$99,200
Leveraged Funding (Non-Checkoff):
The Missouri Soybean Merchandising Council (MSMC) has already provided funding for the purchase of the Weed Zapper. The United Soybean Board has funded some previous at-harvest weed seed destruction research. None of this previous research included an evaluation of the weed electrocution as a means to manage current herbicide-resistant weed species plaguing soybean production. However, results from USB-proposed and ongoing research will complement this proposed research by advancing our understanding of the most effective and economical non-chemical options in soybean.
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Institution Funded:
University of Missouri
$99,200
Brief Project Summary:

Weeds with multiple herbicide resistances and a lack of new chemistries have resulted in the need to assess and integrate non-chemical weed control methods with herbicides for more effective weed management programs. The project evaluates weed electrocution in six states with the Annihilator 6R30 weed zapper as a method of preventing weed seed production for common Midwest weeds. A second non-chemical treatment is included at each location as a comparison to electrocution, such as in-row cultivation, hand weeding, windrow burning, weed seed grinding mills, and others.

Key Benefactors:
farmers, weed management specialists, applicators, Extension specialists

Information And Results
Project Deliverables

FY21
Research will be initiated in the 2021 growing season. Preliminary data generated will be summarized and presented at winter extension meetings. Video demonstrations of the technology will be posted on social media outlets.

FY22
Research will be completed following the 2022 growing season. Data will be summarized and shared with appropriate extension outlets as listed in FY21. Additionally, data will be shared at technical meetings, and a technical research paper is planned following conclusion of the study.

Final Project Results

Updated January 31, 2022:
All field trials and soybean harvests were conducted during the 2021 growing season at the participating locations. We have collected data from each of the participating locations and have summarized most of the results from the 2021 field trials. The results show variability in control of waterhemp across multiple states and we think we intend to analyze plant and soil moisture content data from the locations to see if either of those factors play a role in the variability observed. Also, we have begun plans for 2022 research, perhaps with a slightly modified protocol at each of the locations. The attached pdf provides a summary of what we have learned thus far.

View uploaded report PDF file

The increasing prevalence of herbicide-resistant weeds in U.S. agriculture has led to increased interest in non-conventional weed control methods, including weed electrocution. The Weed ZapperTM is a commercially-available weed electrocution implement that has become popular among organic and specialty crop producers. In 2021, the Weed ZapperTM was evaluated in conventional soybean systems to determine its effectiveness as a rescue treatment for weeds that escape chemical control. Species evaluated include waterhemp (Amaranthus tuberculatas), Palmer amaranth (Amaranthus palmeri), common lambsquarters (Chenopodium album), velvetleaf (Abutilon theophrasti), giant ragweed (Ambrosia trifida) and giant foxtail (Setaria faberi). The experiment was conducted in Illinois, Indiana, Iowa, Kansas, Nebraska, and two locations in Missouri. Due to regional differences and the time in between treatment at each location, soybean height ranged from 12 to 40 inches, and soybean growth stage ranged from R1 to R6. Weeds were electrocuted at speeds of 3 or 5 mph. An additional non-electrocution rescue treatment was evaluated at each location for comparison. The comparison treatments were selected based on the resources available at each location and included interrow cultivation, an interrow mowing device, rope-wick herbicide application, sprayed herbicide applications, and harvest weed seed destruction. Visual control ratings indicated that speed of electrocution had no effect on weed control. However, there was an effect of weed electrocution on the control of different weed species. Electrocution provided highest control of giant ragweed (99%), followed by waterhemp (70%), then statistically similar levels of control of Palmer amaranth (43%), giant foxtail (30%), and velvetleaf (20%). Although waterhemp control averaged 70%, control was extremely variable and ranged from 9 to 82% across the five locations that contained this weed. The reasons for this variability will be explored in 2022 research, and modifications will be made to the protocol to enable more optimum timing of electrocution across all locations. Overall, the results from 2021 trials indicate that weed electrocution and several other non-chemical techniques have promise for integration into a soybean system, and compared to harvest weed seed destruction, they have the benefit of targeting the weeds prior to seed formation.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.