As a greater spring barley crop is anticipated this season, getting the most out of the crop is key, with several concerns highlighted in a recent CPM/FMC survey. CPM has delved deeper into some of the key issues ahead of spring drilling.
If nothing has germinated over the winter, it could be that we see an influx of weed issues over the coming months.
By Charlotte Cunningham
Following a difficult autumn drilling window which left many growers unable to sow winter crops, the chances are there’ll be a lot more spring cereals put into the ground this season.
Of course, this puts additional pressure on spring crops— with farmers looking to squeeze every penny out of every acre to minimise losses from the lack of winter cereals.
One thing that could challenge this is a heavy weed burden— particularly in barley crops— meaning it’s more important than ever to ensure you have a robust control programme in place ahead of the spring.
What are the most important broadleaf weeds in
your spring barley crops?
But what are the most problematic weeds in spring barley that growers ought to be aware of? In a recent survey carried out by CPM and FMC, 74% of growers revealed that cleavers were their main broadleaf weed issue, followed by chickweed and mayweed which gleaned 40% and 35% of the votes, respectively.
“Cleavers have always been a problem weed,” says Adam Espir, sulfonylurea specialist at FMC.
However, despite their severity, Steve Cook, agronomist at Hampshire Arable Services, says spring-germinating cleavers can be straightforward to control. “What we can say, is that cleavers are incredibly competitive weeds that can make crops very messy. However, the spring-germinating types are actually quite small and easy to control— it’s the winter ones that tend to cause a bigger issue.”
AICC agronomist, Sam Lawrence says cleavers are also the number one priority for him, however, there are other types of weed that aren’t commonly mentioned but are worth keeping an eye on. “Black bindweed and fat hen are important to look out for. They’re spring polygonum weeds and they’re very competitive. Fat hen in particular is very leafy and grows right up through the crop.”
How has the broadleaf weed situation in spring
barley changed in recent years?
According to Steve, cranesbill is one weed that’s been increasing in presence— though only an issue for 18% of growers— and groundsel is one that Adam has seen a rise in. But has the overall broadleaf weed situation in spring barley changed in recent years? According to 67% of farmers, the answer is no —it’s stayed the same.
However, Steve says the direction of weed challenges all comes down to seedbed conditions and germination, which could be different to the norm this spring. “If nothing has germinated over the winter, it could be that we see an influx of weed issues over the coming months.”
Though this hasn’t been the case for all growers, with 18% noting that broadleaf weed issues have got worse for them.
So, what could be causing this?
“It could be down to a number of things, that are worth considering if your weed burden has got significantly worse,” says Adam. “For example, if you have recently started growing spring barley on rented ground that’s been in a different crop, or maybe you need to alter the cropping due to the weather, then the ground may have a higher weed pressure.”
Which pre-em actives did you use for broadleaf
weed control in spring barley last season?
Sam believes the change in tillage methods over recent years could also have a role to play. “There’s quite a lot of minimum tillage these days and from my experience this sometimes leads to an increased weed burden.
“While the plough isn’t great for the environment, it does do an awful lot for weed control.”
Though the weed picture has stayed the same for most, what has changed is the control programme.
The survey revealed that 42% of growers are now using more pre-emergence herbicides, however, Steve says this is more likely as a result of increased grassweed pressures from yield-robbing weeds such as blackgrass.
Adam agrees and believes the move towards spring cropping in order to deal with severe grassweed issues could, in fact, have repercussions on barley crops. “As we know, blackgrass is a huge problem for winter cereals, and many people are using spring alternatives to try to control the problem. While spring barley is a competitive crop, there’s often the need to use a pre-em which is primarily for grassweed control, although they do provide some broadleaf control.”
Perhaps rather interestingly, when looking specifically at spring barley, 31% of growers revealed all their crop received a pre-em residual herbicide last season. At the other end of the spectrum, the same percentage said none of their crops received a pre-em treatment, while 25% said less than half of their spring barley did and 13% highlighted that more than half of their spring barley was treated with a pre-em residual herbicide, so what’s the best approach?
Which post-em products did you use for broadleaf
weed control in spring barley last season?
According to Steve, drilling date and weed presence should dictate decision-making. “With the pre-em chemistry, it’s really about targeting blackgrass. The later in the season that a crop is drilled, the less likely you are to need it. If you’re drilling in late Mar/early April, more often than not, you shouldn’t need it.”
Sam agrees: “It’s important to reinforce that pre-em herbicides should only be used for grassweed issues. But if you do feel you need to use one, assess what’s in front of you and base your decision on that.”
In terms of specific actives for broadleaf control, of those growers who did use a pre-em last season, flufenacet-based products— such as Liberator (contains diflufenican) and Crystal (contains pendimethalin) — appeared to be the active of choice, with over half (57%) of growers using them.
“If you’re not targeting blackgrass, there’s no point in a pre-em— if you’re planning a spend, this could probably be better directed on a targeted broadleaf product later in the season,” says Steve.
Pendimethalin was the top choice for 35% of growers and this does provide a good level of control in broadleaf weeds, adds Sam. “It’s great for meadow grass and gives you a good level of early control.”
Looking at post-em products, the majority of growers (77%) said they opt for sulfonylurea herbicides such as Jubilee SX, Harmony M SX and Ally SX or Ally Max SX.
“What’s good to see is that while SU herbicides are most popular, people are using a range of products which I imagine is based on specific weed issues,” says Steve. “It’s horses for courses when it comes to weed control and particularly this year, growers ought to take the time to look at what they’re dealing with, do an assessment and then apply a product based on what is appropriate for those weed issues.”
A third of growers (31%) revealed they opt for the age-old phenoxy herbicides as their product of choice, however, Adam believes this is usually in combination with something else. “Phenoxy herbicides are actually often tank-mixed with SU herbicides.”
New active Arylex gleaned 37% of the vote, and Adam says this could prove to be a very important tool in the arable armoury. “Having access to a new mode of action is incredibly beneficial for growers and for weed control. However, there are gaps with Arylex which SU herbicides can fill, so they will continue to be important for broadleaf weed control.”
Turning to focus to grassweeds, although blackgrass seems to often be the most troublesome grassweed, it’s actually wild oats that are causing the biggest issue for spring barley growers. So with 76% stating that this is their most important weed, just how bad can wild oats really be?
“Wild oats are a lower yield threat, but they are much more competitive than blackgrass and will often come through no matter when or where crops are sown. As well as this, it seems to be a burden nationwide, so I can see why it’s the key focus for so many growers,” explains Steve.
Sam agrees: “Depending on the individual farm, wild oats can be hugely detrimental. In my experience, I’ve seen the burden return, even on clean farms.”
Though it didn’t claim the top spot, it’s not to say that blackgrass isn’t still a major issue, with 59% of growers noting it as the most important weed for them to manage. “If spring barley is sown early, blackgrass shouldn’t be too much of an issue,” says Steve. “It’s a very competitive crop and you’d have to have a lot of blackgrass to get much past spring barley.”
Annual meadow grass was also highlighted as a concern by almost half (42%) of growers. But according to Steve the severity of this could be dependent on location. “It’s not something I see an awful lot of anymore, which I think is likely to be due to growers using so many weed control products on winter crops.
“However, a lot of spring barley is grown in the North where it is a problem. This is where treatment like a half rate of flufenacet will come into its own.”
And it seems flufenacet is the product of choice when it comes to grassweed control too, with 59% of growers noting products such as Liberator and Crystal as key components in their crop protection programme.
However, pinoxaden products also proved popular, with 57% of growers stating that they opt for products such as Axial Pro to control grassweeds.
“Axial Pro is great for wild oat control and with the weed proving itself to be a key concern for growers, there’s no surprise that this is such a popular tool for growers,” says Steve.
While products such as Foxtrot (fenoxaprop) have perhaps traditionally been the more favoured product of choice when it comes to wild oat control in spring barley, opting for something like Axial Pro can give more flexibility, he adds. “If barley is already stressed or struggling, fenoxaprop products can actually damage the crop. With something like Axial Pro, growers have a bigger window to work with which means more flexibility. The downside is that it can be expensive, but this can be overcome by targeting usage.”
But in contrast, Adam says there are sequencing issues to be aware of with products such as Axial Pro. “For example, if you treat with a hormone first— such as a phenoxy— you have to wait 21 days before you can go on with an Axial product, by which point, the oats may have gotten very big and difficult to manage.”
What’s more, there has been greater interest in the product lately, he adds. “It’s a competitively priced product and with the decline in resistance and the sequence issues in alternatives, something like Foxtrot could prove to be more attractive for growers.”
Top tips for weed control in spring barley
With more spring barley anticipated to be planted this year, what’s the advice from our experts on how to maximise weed control this season?
- Ensure seedbed conditions are as good as possible— the quicker the crop gets away, the more competitive it will be.
- Only use pre-em herbicides where required, providing the seedbed is good enough. If crops haven’t gone in well then stick to broad-spectrum mixtures for broadleaf weeds.
- Don’t spray too late when it comes to post-em sprays.
- Don’t make decisions based on routine— reflect on what’s in front of you and prepare for this year being different to the norm.
- Get some nitrogen on to the crop as soon as you can.
Winner announcement
Congratulations to our winner Tom Excell from Newmarket who responded to the CPM/FMC survey on spring barley weed control and has won the fabulous prize of a pair of Le Chameau wellies.
Tom responded to the survey and completed the tie-breaker question on the secret to success with weed control in spring barley. With a pragmatic approach and regular crop/weed monitoring more important than ever this season, his answer, “attention to detail” impressed the judges.
The aim of the survey was to explore the key weed challenges in spring barley. To take part in the next survey, make sure we have the correct details for you by emailing angus@cpm-magazine.co.uk
