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Southeastern Alberta | Thanks for the post Joel. Good as always. Brings up some thoughts based on my operation.
I have often heard the phrase "there isn't a weed that is resistant to steel yet" and, although on the surface it appears true, I don't think that it is. When we used tillage and summerfallow, we had Russian thistle, wild buckwheat and tansy mustard as our main weed problems. So either small seeded, warm season, or a winter annual. The move to no till has meant a shift to Canada and sow thistle and narrow leaved hawksbeard. Kochia and wild oats are issues in both systems.
A system shift always means that a weed species shift will happen. It seems that there are weeds adapted to surviving under a tillage regime -warm season that start after the crop is growing, small and shallow rooted that can survive a tillage operation or germinate readily with moisture, and prolific seed producers that produce so much seed that near 100% control still looks like a disaster!
Tillage is only a tool (that I choose not to use). Treating it as a magic bullet like we treated glyphosate for the last 20 years will mean we learned absolutely nothing from the beginnings of weed resistance.
As an interesting note, I saw presentation on weed resistance a month ago and they showed a photo about Barnyard grass (I think) that was 'resistant' to hand weeding in rice. What happened is that there were individual barnyard grass plants that looked like rice in the population. Those ones were the ones often missed by the hand weeders and so it resulted in a shift to a population of barnyardgrass that mimicked the look of the rice plants. Just goes to show that we need to use more than one tool to control our problems (not just weeds, but all pests).
Finally, "If weeds aren't resistant to steel, wouldn't organic fields be weed free?"
Obviously with all of your excellent cover crop and no till organic work, that is definitely not the case!
Edited by kirschenman 2/27/2015 09:00
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Should tillage be used to control resistant weeds?
