Performance Story: Harrington Seed Destructor Evaluation at Field Scale in Alberta
Herbicide resistant weeds continue to increase in incidence and frequency, limiting weed management options available to producers. New management strategies are needed for producers to continue to successfully manage their weeds. Harvest weed seed control (HWSC) is a paradigm of weed control that focuses on managing weeds that are being spread by the combine harvester. These weeds retain their seeds until crop harvest, produce weeds at a height where they can be collected, and are successfully taken into the combine. One method of harvest weed seed control that may have a fit in western Canada are the physical impact mills. The original tow-behind Harrington Seed Destructor is an example of an impact mill that is available for testing in western Canada. From 2017-2019, 20 producer fields had research plots established in weedy areas. These plots were broken into either untreated checks, or harvested with the Harrington Seed Destructor. Seedling counts were conducted the following springs (2018-2020). In 2020, weed seedbank samples were also collected. Results of the seedling counts are showing minimal statistically significant differences in terms of reducing weed seedling populations.
There is also next to no statistical evidence of reduced weed populations when considering the above ground seedlings and the seedbank densities as the total weed population. Previous research into seed retention and mill efficacy has indicated that use of the Harrington Seed Destructor or other impact mills should be efficacious in western Canada, at least for certain weed species. Understanding why this study does not match with expectations of previous research is really important. There are some potential design flaws (study too short considering weed seed dormancy, study focussed in highest weed density and proportion controlled doesn’t show significance in 3 years), but there are some additional research gaps (weed seed loss at the combine header, optimizing combine settings to concentrate weed seeds in chaff) that should also be investigated to understand if efficacy of the Harrington Seed Destructor or other impact mills can be improved in western Canada.