Researchers from the University of Missouri recently conducted two field studies to explore the effectiveness of electricity in weed control.
Field experiments were conducted in 2020 and 2021. In the first study, the effectiveness of electrocution on waterhemp, cocklebur, giant and common ragweed, horseweed, giant and yellow foxtail, and barnyardgrass was determined.
Also read: First Australian electro-weeding trial
Electrocution was applied when plants reached average heights and/or growth stages of 30 cm, 60 cm, flowering, pollination, and seed set. Electrocution was applied once or twice, at two different tractor speeds.
Electrocution was more effective at the later plant growth stages. Pearson correlation coefficients indicated that control of weed species was most related to plant height and amount of plant moisture at the time of electrocution. When plants contained seed at the time of electrocution, viability was reduced from 54 to 80% among the species evaluated.
A second study determined the effect of electrocution on late-season waterhemp plants, and also soybean injury and yield. Electrocution timings took place throughout reproductive soybean growth stages. The control of waterhemp escapes within the soybean trial ranged from 51 to 97%.
Yield of soybean electrocuted at the R4 and R6 growth stages were similar to the non-treated control, but soybean yield was reduced by 11 to 26% following electrocution at all other timings.
However, the visual injury and yield loss observed in these experiments likely represents a worst-case scenario as growers that have a clear height differential between waterhemp and the soybean canopy would not need to maintain contact with the soybean canopy.
Overall, results from these experiments indicate that electrocution as part of an integrated program could eliminate late-season herbicide-resistant weed escapes in soybean, and reduce the number and viability of weed seed that return to the soil seedbank.
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