The project will be a comparison of weed electrocution as part of an integrated weed management program compared to a second, non-chemical treatment. The work will address questions pertaining to overall effectiveness of weed electrocution on common weed species; effects of weed density; and effects of tractor speed. For weed electrocution treatments, the Annihilator 6R30 Weed Zapper will be utilized. The University of Missouri weed science program recently purchased this machine with funding provided by the Missouri Soybean Merchandising Council. The group is willing to transport the machine to multiple sites within the North Central region for a more comprehensive analysis if funding can be secured. A second non-chemical treatment will be included at each location as a comparison to better evaluate the feasibility and efficacy of the Weed Zapper. The comparative treatment will be selected by the investigator at each location and options include in-row cultivation, hand weeding, windrow burning, weed seed grinding mills, among others. Additional locations for this research include Illinois, Indiana, Iowa, Kansas, Missouri, and Nebraska. The size of the research project and weed species targeted will vary by location based on available equipment and predominant weeds at each site. Proposed species include Palmer amaranth, waterhemp, giant ragweed, Marestail, common lambsquarters, and velvetleaf. The target stage for electrocution treatment will be once the majority of the weed species of interest has emerged through the soybean canopy and prior to weed seed set.

To evaluate weed electrocution as a method of preventing weed seed production for some of the most common weeds encountered in Midwest soybean production systems.

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.

Updated March 26, 2021:
We have distributed our field research protocol for the 2021 season to all participating universities. All locations are planning out their field trials accordingly. Over the course of the next month or so, soybean planting will begin at some locations.

Updated October 21, 2021:
All field trials were conducted during the 2021 growing season at the participating locations. The Weed Zapper was transported to all the participating states at the appropriate times during the growing season and the electrocution treatments were applied. Each cooperator has been conducting weed control evaluations since this time and we are now waiting on soybean harvest to occur at each of the locations. We will be gathering data from each of the participating locations and summarizing all of the 2021 results soon.

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

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.

Weeds with multiple herbicide resistances and a lack of new chemistries have resulted in the necessity to integrate non-chemical methods with herbicides for the most effective weed management programs. Yet there remain many questions about the efficacy and efficiency of non-chemical methods as viable weed management options for U.S. soybean producers. Research is lacking on whether weed electrocution is a feasible and effective option for conventional soybean producers in the North Central region.