Ben Taylor-Davies black grass talk

Discussion in 'Cropping' started by Feldspar, Nov 6, 2018.

  1. @bentd76

    @bentd76 New Member

    So........ The problem with trying to cover a huge subject in a few hours often provides more questions than answers!

    The main points are

    1) Any species that has 'found' it's ecological niche will thrive (this niche is often not available in their natural environment) such as Himalayan balsam, Japanese knotweed, grey squirrels, rabbits, blackgrass etc

    2) Highly successful weeds in an agricultural situation are there because they produce a huge amount of seed and thrive in an environment that is provided for them.

    3) The more seed, the more plants, the more mutations, the more diversity in the population, the more successful the plant is to change and adapt. Evolution is simply a numbers game. Minimum of 1 trillion blackgrass seeds produced every year in the UK

    4) Crop competition is king - simple, grow an incredibly thick crop of high biomass crop with no gaps, weeds are often smothered and cannot compete, the greatest failings in the Uk to achieve that is often water logging but not exclusively.

    5) Blackgrass is not a 'marsh' species, the fact it is able to produce secondary aerenchyma means that in wet and waterlogged situations it is able to last longer than any of the UK crops (rape has no ability to produce aerenchyma, wheat/cereals has had met of its natural ability bred out) simple selection, if you have wet areas, you have little or no crop competition and therefore where often you find the worse blackgrass areas - however this is not the only place!

    6) There are many words to describe individual populations within a species, most seem, around the world to adapt the word 'ecotype' the chances are if you are doing something very different from your neighbour, your blackgrass will be a different ecotype.

    7) The reason a spring crop is so successful the first time you grow it? simply the blackgrass is used to growing in a winter situation and has been outfoxed. Keep doing it and the population will soon adapt.

    8) If you mix everything up all the time, cultivations, crop rotations etc, you will end up with a population that can has the ability to produce blackgrass in each scenario you present it - as a percentage game the numbers may be low to begin with, but will build and although a small percentage will become a worsening problem year on year.

    9) Herbicides, synergy and antagonisms...... It was made clear to me, anywhere I travelled. A driver for resistance is applying a sub lethal dose of a herbicide, this can be caused by a huge amount of factors including spray water complexing, purposely cutting the rates and stress. It is well understood that applying many herbicides to stressed weeds will give poor control, e.g frost, water logging and drought etc yet on many labels around the world, stress is also labelled as "a previous application of a herbicide". It was suggested that Atlantis resistance was probably caused by pre ems causing a plant to become severely stressed and then when Atlantis was applied the plant under stress was unable to take in a lethal dose and therefore any survivors would quickly form resistance.

    10) Herbicide stacking etc works very much on the principle that soil applied herbicides have a huge range of inefficacy due to the soil not being the 'perfect' carrier and more often than not sensitive plants will miss the application of the residual all together, these unaffected survivors can be removed by other residuals with different solubilities, KOc values, half life and volatilisations. It especially accounts for Avadex adding a bit extra because it is a totally different application method and formulation and often the reason why it seems to compliment sprayed on pre ems so well. However it also explains the huge variation in its control.

    11) The generalised answer is fairly simple, improve the environment that doesn't favour blackgrass selection, trying to find the utopia is hard, if you can provide an environment that produces consistent crops that are competitive from field boundary to field boundary in any scenario, the blackgrass pressure will subside.

    Hope this explains what I have seen in a bit more detail, but probably as ever asks more questions than it answers!
    Bob lincs, Brisel, Feldspar and 7 others like this.
  2. Flat 10

    Flat 10 Member

    Fen Edge
    Very eloquently put and some interesting snippets in a comprehensive whole, good work @bentd76. However I don’t think much about it is surprising (and that’s not your fault Ben you are reporting facts as you found them) and won’t be changing much as a result of it. I also suggest that if you find much of it surprising then you need to read it, as you have some catching up to do,
  3. fudge

    fudge Member

    Ok but what practical difference does that make? The net result is the same bg is favoured by wet conditions. It’s foolish to ignore drainage and cultivation techniques that improve water infiltration.
    Flat 10 likes this.
  4. @bentd76

    @bentd76 New Member

    Or of course develop a cereal with aerenchyma - ancient ecotypes of wheat, barley and oats all had the ability to form secondary aerenchyma far better than it does today. Problem is, the innovation could be there, but currently only really looking at varieties that give a 2% yield increase.
    Megswell and Flat 10 like this.
  5. fudge

    fudge Member

    Such varieties won’t see the light of day unless they are economic though. From the growers perspective that’s a seems a long way off. Even then systems would need to play the numbers game with bg.
  6. farmerfred86

    farmerfred86 Member

    Interesting Ben, Why the hell are we held to ransom by the AHDB list with Robigus breeding? If there are other varieties out there in Europe more suited with aerochyma why are we not utilising them especially after paying the royalties!
    Woldat likes this.
  7. Certain in acerbic mode atm! I'd better be careful what I say.
  8. Flat 10

    Flat 10 Member

    Fen Edge

    I have high expectations of you.....
    Brisel and Feldspar like this.
  9. Brisel

    Brisel Member

    Thank you for coming into this debate (y) I look forward to reading your paper.

    Point no 9 - resistance. The quickest way that BG developed resistance in my experience was through a number of factors - suboptimal application practices, including coarse sprays on a fine target, water cation complexing but most of all, applying it to dinner plate sized plants in stem extension in cold weather in March/April.

    Point number 10 - look at NIAB TAG data on herbicide programmes & have a chat with John Cussans if you haven't already done so. There is consistent trials data that shows stacking herbicides showing an improvement but I agree with your point about one herbicide creating stress that limits the efficacy of another.
    fudge likes this.
  10. fudge

    fudge Member

    I agree with that and would add residual herbicide cannot cover a period much longer than four weeks which in practice means later drilling. Really for autumn cereals the later the better from a herbicide efficacy point of view. Which incidentally also gives them a better chance of being applied with the moisture they require to work.
    Brisel likes this.
  11. Brisel

    Brisel Member

    The half life of a herbicide is related to temperature and solar radiation, so will last longer the later it is applied assuming it is still pre emergence of the weed.
  12. Half life for early October aplied at 400 ft in Lincolnshire on heavy cold land will be longer than Dorset on south facing chalk
    Brisel likes this.
  13. Hindsight

    Hindsight Member

    An additional comment regarding residual herbicide and later sowing - at the end October into November growth slows and thus the blackgrass is small for much longer than end September when it will be growing quickly. Thus a combination of more moisture and slower growing blackgrass target plant.
    Oat, fudge and Brisel like this.
  14. Been out walking middle drilled block of wheat. Annoying amount of black-grass come through and brome. For all we talk about black-grass, I have spent more time worrying about brome over the last few years than black-grass. But I digress. Some of the these two leaf BG are clearly being affected by the pre-em, but I'm confident that enough of them will be left to need Pacifica. We have enough brome to justify by itself and if done in the spring there will be some wild oats which will help justify the application if we wait that long.

    There seems to be a clear trade-off here. Pacifca now on small plants which are being affected by the pre-em, or in the spring on much larger plants (will have to wait a while for temperatures to rise to get decent brome control) which will have got over the pre-em. NIAB results show better black-grass control in the autumn than in the winter, and I think Bayer's results are similar (?). To me that indicates that it might be better to take the disadvantage of the stressed plants not taking as much chem up rather than the disadvantage of applying to much bigger plants that are tillering fast.


    Also, who reckons it's still warm enough for Pacifica?
  15. Temperature surely good to go for Atlantis...Pacifica is spring only IIRC but might be wrong.
    Brisel and Andy26 like this.
  16. Andy26

    Andy26 Moderator

    You cannot apply Pacifica in the autumn, after 1st of Feb only.
    Brisel likes this.
  17. Thanks. How good is Atlantis on brome? Seem to remember being told it's not good enough.
  18. Godber

    Godber Member

    NW Essex
    We have a few BG plants here but they do look dickey... hoping they die(some will) and no more come up, will look again in the new year.
    With the warm weather forecast and good field conditions its tempting to go with Pacifica.
  19. Andy26

    Andy26 Moderator

    Not as good as Pacifica, Monolith or Broadway Star.

    You can use Broadway star in the autumn if Bromes are more a problem, add some more flufenacet at the same time?
    SilliamWhale and Brisel like this.
  20. That's what I thought.

    I think there's enough black-grass that it would be nice to use something that will at least do something for black-grass. Atlantis / Pacifica still has useful amount of control here.

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