37 www.seed.ab.ca | spring.2019 presents a similar issue — as does wild oat, but for a different reason. During Tidemann’s PhD studies, she found that wild oat seems to shed its seed prior to crop harvest. “So, what we did is we compared early-maturing crops (peas followed by winter wheat) to ‘normal’ maturity crops (wheat and canola) to late-maturing crops (faba bean and flax),” she says. “We collected chaff off the plots when we harvested and counted how many wild oats we collected in each plot (which would be the ones to go through something like an HSD). We also compared swathing and straight cutting in each of those rotations. The idea was that we should collect the most wild oats in early-maturing crops, and should collect more by swathing versus straight cutting.” Preliminary results show that more wild oat seeds are collected when crops are swathed, but Tidemann says more are not necessarily collected with earlier-maturing crops. “We still have to do a final analysis on this data to see if those preliminary results are true at all sites and years, and then we need to try and figure out why,” she says. “It’s possible that wild oats are more variable than we suspected, which makes it harder to manipulate agronomics to collect more seeds. More to come on this project in the next year or so.” Tidemann notes that a couple of producers in the province are trialing a harvest weed seed control method called chaff lining (see sidebar) that’s less expensive than seed destructors. At this point, she doesn’t think most producers see the cost of seed destructor systems being worthwhile. Epp reports that the iHSD currently costs about $150,000 and the Seed Terminator rings in at about $100,000. However, while Tidemann states that something like chaff lining may be easier to adopt initially, a lot of the same operational principles apply in terms of, for example, seed capture/retention issues. In terms of when seed smashers might be used on a widespread basis, Tidemann says that at least two other factors are at play besides cost of the equipment, including her research results and the rate of spread of herbicide resistance. “I hope over the next few years we start seeing interested producers. I hope to do some more exploration into what's going on with wild oat seed retention, and also look forward to trialing something like chaff lining.” An enjoyable part of Tidemann’s work is seeing producers get interested in ways of solving problems like weed control. “They have so many ideas and so many different perspectives about what will work on their farm and why,” she says. “I love hearing from them and hearing what they’re thinking about trying.” Treena Hein The Harrington Seed Destructor works well on cleavers and volunteer canola. Photo courtesy of Dr. Breanne Tidemann Seed testing experts in purity, germination, vigour and seed health. 1-866-980-8324
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