Factors affecting weed seed devitalization with the harrington seed destructor

The Harrington Seed Destructor (HSD) is a new machine developed in Australia to manage weeds normally spread by combine harvesters. It has been highly effective in Australian cropping systems. To evaluate how it would work in western Canada it was operated unattached to a combine where a known number of weed seeds and a known amount of chaff was input into the machine to determine how many weed seeds were killed by the machine. Factors that were tested included weed species, weed seed size, weed seed number, chaff volume being processed, and chaff type (crop type) that the weed seeds were in. There was differences in control by weed species but control ranged from 97.7% to 99.8%. Various sizes of volunteer canola showed that control increased with larger seeds, however the difference in control between our smallest sized seed and our largest sized seed was less than 1%. High levels of weed seed kill was observed no matter how many weed seeds were processed at one time. Increasing chaff volume initially increased weed seed kill but eventually resulted in decline, however control was greater than 97% in all chaff volume treatments. There were differences in control based on chaff type (i.e. crop type), with a range between 98% and 98.6% weed seed kill. Overall the five factors studied did have some impacts on how well the HSD killed weeds, but the differences are likely too small to have much effect within a farmer's field. Overall the machine is quite effective at destroying seeds that make it into the machine and may be effective in producer fields in western Canada.