Contributed by Luisa C. Baccin and Marcelo L. Moretti, Oregon State University Department of Horticulture
The research project led by Luisa Baccin, a Ph.D. student at Oregon State University under the guidance of Dr. Marcelo Moretti, is pioneering the use of electrical weeders as an alternative for weed control in organic systems. This innovative technology offers an eco-friendly way to manage weeds. Electric weeders use front applicators that cover about 4 feet and zap weeds with a discharge of alternated electric current. The electric current travels through the plants, disrupting their cells and causing them to dry out and die. This method is safe for the environment, as it doesn’t leave residues or affect soil health. It’s a promising choice for farmers and growers seeking organic weed control options.
Figure 1. Tractor-powered electrical weeder (EH30 Thor) applying an electric current to the side of the weed mat and on top of the sawdust mulch.
The study focuses on a tractor-powered electrical weeder’s efficacy and crop safety in organic highbush blueberries. Conducted in an organic-certified area with Duke blueberries established in the fall of 2022, the field is set up to test the effects of different mulch types (sawdust, weed mat, and bare ground) in combination with electric weed control at both 1.25 and 0.25 mph, as well as traditional mowing. Additionally, a nontreated plot was included to assess the impact of weed competition on the blueberry plants.
Over the course of six applications between May and October 2023, the effects of these treatments on blueberry growth, soil health parameters, and weed control were evaluated. Our results revealed that electricity did not negatively impact the growth of the blueberries, nor the physical and chemical properties and biological indicators of soil health. The technology also proved compatible with sawdust mulches, commonly used in organic blueberry farming.
For the nontreated plots, weed competition led to a 28% mortality rate for the new blueberry plants versus 0% mortality for treated plots. When comparing all weed management strategies to nontreated weedy plots, we observed up to three times larger blueberry canopy volume and up to 1.5 times longer shoots. These results highlight the vital role of effective weed control in the early stages of crop development.
Figure 2. Study plots with electric weed control (left) vs nontreated (right) showing the difference in growth of blueberry plants.
Weed control efficacy was particularly notable in electricity. The electric weed control (EWC) outperformed mowing in all mulch types. By the end of the season, the number of weed species remaining on the EWC plots was drastically reduced by 10-fold. The new technology was effective in suppressing perennial weeds such as field bindweed and Canada thistle, reducing their spread in the field.
Figure 3. Nontreated (left), electric weed control at (1 km/h) in the center, and a close-up picture of the EWC treated plot showing the effect of electricity on Canada thistle.
This research was funded by USDA NIFA OREI Grant number 2021-51300-34911. This is a multi-state and long-term project, and we will continue to evaluate the productivity and cost-efficiency of electrical weed control in highbush blueberries and other organic crops. You can find more information on our website and our YouTube channel. Stay tuned for more updates as we explore the potential of electrical weed control in organic agriculture.