Look up sexual reproduction and dna recombination, the process creates diversity. Otherwise we would all reproduce asexually to produce clones. More offspring = more diversity. As to the second part no I don't think so.
Ben Taylor-Davies black grass talk
- Thread starter Feldspar
- Start date
I haven't read Ben's Nuffield recently but agree with some of his points. You do need a mix of strategies to control pests & weeds but if you look through your herbicides trials work @Feldspar you'll see the increased control by using sequences over relying on one so I don't buy the sequence antagonism unless the actives are all applied close together as you would for a pre em then peri em stack.
I've been selecting late spring germinating wild oats by putting a dirty field for brome into continuous spring cropping. There's one headland where I get a flush of wild oats in June every year despite knowing I got the Axial + Adigor contact herbicide on in good conditions in late May/early June onto small plants & had a good kill of what was there.
I've been selecting late spring germinating wild oats by putting a dirty field for brome into continuous spring cropping. There's one headland where I get a flush of wild oats in June every year despite knowing I got the Axial + Adigor contact herbicide on in good conditions in late May/early June onto small plants & had a good kill of what was there.
- Location
- Suffolk
I've been giving this more thought and there is an elephant in the room (or 2)...
If we take the example (and picture in his report) of the blackgrass that emerged between the subsoiler legs in undisturbed ground. Presumable that farm had been no-till or strip till for the 9 years he says it took to create this problem. If in that time the farmer had, on just one occasion used a different cultural control such as ploughing after 4 years he would have reset the self selecting problem (or at least reduced the number back to manageable levels).
That is why I asked the question about ploughing at the meeting. If ploughing and its effect on soil health is rubbish (you have to wonder!) then ploughing every 4/5 years in between a no-till system should prevent the blackgrass from self selecting?
The other elephant in the room is the comment we have all heard "blackgrass below 50mm looses 80% per year" (or words to that effect). If thats truly the case then 5 years of no-till should mean there is no deep blackgrass still alive and the shallow blackgrass will have been destroyed by 5 years of glyphosate applications aloing with pre-ems.... but it doesn't!!!!!!
The answer to me seems to be what Ben said about is selective nature. BG doesnt like wet soils, heavy clay or anything else! Its just very selective and has an excellent ability to survive. Whatever we do it will keep adapting. So we have to keep adapting too!
If we take the example (and picture in his report) of the blackgrass that emerged between the subsoiler legs in undisturbed ground. Presumable that farm had been no-till or strip till for the 9 years he says it took to create this problem. If in that time the farmer had, on just one occasion used a different cultural control such as ploughing after 4 years he would have reset the self selecting problem (or at least reduced the number back to manageable levels).
That is why I asked the question about ploughing at the meeting. If ploughing and its effect on soil health is rubbish (you have to wonder!) then ploughing every 4/5 years in between a no-till system should prevent the blackgrass from self selecting?
The other elephant in the room is the comment we have all heard "blackgrass below 50mm looses 80% per year" (or words to that effect). If thats truly the case then 5 years of no-till should mean there is no deep blackgrass still alive and the shallow blackgrass will have been destroyed by 5 years of glyphosate applications aloing with pre-ems.... but it doesn't!!!!!!
The answer to me seems to be what Ben said about is selective nature. BG doesnt like wet soils, heavy clay or anything else! Its just very selective and has an excellent ability to survive. Whatever we do it will keep adapting. So we have to keep adapting too!
Feldspar
Member
- Location
- Essex, Cambs and Suffolk
I'm not so sure it will happen that quickly and you can still get in a mighty muddle in 5 years. Think of the cost of dealing with populations of several hundred black-grass plants per sq m even with a robot and a laser. You're going to need a LOT of robots to cover the ground whilst weeds are still small enough to be able to be killed with a laser. Robots aren't exactly going to be cheap. I think we shouldn't place too much faith in this as a panacea in the short term. I'll have a friendly bet with you on this one.
- Location
- Suffolk
Possibly although images of mimicry were astonishing... Resistance to hand rouging shown in China will soon prevent a robot from recognising the weed. Robots cant come soon enough though as we are loosing chemistry so fast through resistance or regulation!
Feldspar
Member
- Location
- Essex, Cambs and Suffolk
Good point about mimicry wrt robot targeting. Hadn't thought of that.
Don't take me so literally!
Please explain. The plants changed how they looked?! I thought the stuff about being resistant to rogueing was a joke!
Feldspar
Member
- Location
- Essex, Cambs and Suffolk
No it wasn't. He gave the example of some weed that appears in rice. Over time it had changed appearance to look more like rice so it couldn't be rogued until it actually headed.
- Location
- Suffolk
He had an image from China (Not sure if it was black grass but may well have been). Basically they've been hand rouging there long enough that the weeds now mimic the rice plants so they cant be hand rouged. They can only see the difference at ear emergence!
Feldspar
Member
- Location
- Essex, Cambs and Suffolk
Slightly slower at typing than me! But pleased my memory isn't completely useless.
- Location
- Suffolk
Got to be quick - If you're too slow black grass will probably take over the farming forum!
Feldspar
Member
- Location
- Essex, Cambs and Suffolk
I was thinking back to his map of where black-grass was in the world. There was one dot somewhere in Outer Mongolia or thereabouts. Got to feel sorry for the bugger who's the only person to have it in about 2000 miles.
- Location
- Suffolk
Do Mzuri have a dealership there? 
- Location
- Lincolnshire.
Spot on. I think taking a look at all the research can throw up interesting ideas but bg problems do seem site specific. That means managers should back there own judgement and adopt the techniques that reduce numbers on a particular site. For example there are people who find winter barley works in their rotation, but here it has no part to play because the yield doesn’t compare with second wheat and the weed seed return too high. One can spend too much time looking over the hedge.
The rougeing had selected these plants by leaving them.
Feldspar
Member
- Location
- Essex, Cambs and Suffolk
Yes, that was my understanding.
Obviously.....
I hadn't meant to be patronising, but we're helping the adaptors by taking out the rest, just as herbicides select the resistant plants by removing the competition. I'm probably not explaining myself very well.