Join the quest for weed seed solutions

Farmers with tricky grassweeds to control are invited to take part in an exciting new farmer-led project as part of the second year of BOFIN trials on harvest weed seed control (HWSC).

The call is out for Seed Scouts – farmers who will monitor and sample grassweeds in their crop as harvest approaches and send these in to NIAB for analysis. Those interested should contact OR

Every farmer who takes part in the study will get tailored information on the likely level of efficacy of HWSC, which opens up a new chemical-free form of grassweed control and helps reduce dependence on glyphosate. The Seed Scouts will also be taking part in the UK’s first ever farmer-led survey of grassweeds left standing at harvest. Experience in other countries has shown this is a valuable window to tackle tricky grassweeds, such as ryegrass and meadow brome.

Also revealed during the webinar will be plans for further on-farm trials of the Redekop Seed Control Unit (SCU) that will take place on three UK farms this harvest, building on last year’s results.

Anyone with an interest in the technology can register to attend the webinar and will join the BOFIN Seed Circle tracking progress and helping to shape the project. Farmers in particular are encouraged to sign up as Seed Scouts and take part in this important weed survey

Will Smith, research agronomist at NIAB will talk through how to sample crops, the help provided to Seed Scouts and how the trials will be run with the SCU.

Adam Driver of Driver Farms, Suffolk, leads the project and has an SCU fitted to his Claas Lexion 8800. He’ll share experiences from last harvest and discuss what he’s looking to gain from this year’s trial.

Trevor Thiessen, co-owner and president at Redekop Manufacturing will join the discussion from Canada, offering further insight into the SCU and bring us up to date on latest developments.

On the 18 May 2023 a webinar took place discussing the Harvest Weed-Seed Control project. The panel addressed questions and discussed suggestions live from webinar attendees. The focus of this webinar was to bring in prospective Seed Scouts to refine how the sampling will work.

If this webinar seems like something you feel you missed out on, please contact OR to request a recording of the webinar!

Year one results

While this year’s trial is funded by the Defra Farming Innovation Programme, delivered by Innovate UK, it carries on from a farmer-led study, funded by Redekop into HWSC.

Last year, three UK farmers took part in the trial, coordinated by BOFIN, during which Will drew up protocols for sampling and analysing the weeds left standing at harvest, building on NIAB expertise in this area.

“The only way HWSC will work is if the seeds are available to the machinery at harvest,” notes Will. “We currently know little about how much viable seed goes into the combine – there’s very limited work on this in the UK and Europe.”

In 2022, three Redekop SCUs were imported and fitted to the farmers’ combines prior to harvest, with the help of Oria Agriculture. Jake Freestone of Overbury Enterprises in Worcestershire has one on his John Deere S790i combine and has a bit of a problem with meadow brome.

Italian ryegrass is grassweed enemy number one for Warwickshire grower and Velcourt farm manager Ted Holmes, who been trialling a unit fitted to his New Holland CR9.90.

And in Suffolk, Adam has noticed a build-up of blackgrass in the chaff lines behind his Claas Lexion 8800, running on a no-till 12/36m controlled-traffic farming system. He’s also hoping the SCU keeps meadow brome in check.

Two fields on Ted’s farm were closely monitored, in winter and spring barley, and both had a high Italian ryegrass population. “There are two critical monitoring periods,” explains Will. “Firstly, we want to know the population of viable seed standing at harvest, which involves taking representative samples just before the combine goes through. “Then we monitor what emerges into the following crop once autumn cultivations and drilling are complete.”

Will’s now developed a protocol for farmers to take their own pre-harvest sample. “It’s impractical to have to wait for a weed scientist before you get the combine out. But just a little instruction on how to sample helped the farmers take good, representative samples. They sent these into NIAB for assessment.

“For Italian ryegrass the figures were 62% in Warwickshire in winter barley and 87% for spring barley. These figures are high, but testing of the seed found that a lot of the IRG seed in the spring barley was unviable, and we think that was due to the hot, dry conditions.”

Effect of the Redekop SCU in winter and spring barley:

The surprise result in the 2022 sampling was blackgrass in a field of winter wheat Adam monitored in Suffolk. “We found 54% of this was retained at harvest, so there’s more available to the SCU than we had thought. But we should consider the hot and dry conditions of the 2022 harvest,” notes Will.

Source: NIAB, 2022, Warwickshire. IRG seed shed into winter barley (left) and spring barley (right), with emerged seedlings counted on 26 October in oilseed rape and winter beans respectively. Note: the spring barley field was subsoiled, which may have introduced more seed from previous years. Figures shown are averages across two strips in each field, with multiple transects taken in each strip.

Following crop

Will returned to the farms in late October to make a full assessment of emerged grassweeds. “In the field following winter barley in Warwickshire there was a 60% reduction from the SCU. In spring barley, the result was lower – a 44% reduction – but then a lot of the seed was unviable, so we’d expect a lower result.”The eventual aim of the study is to gather data across a range of crops and key grassweeds of the amount of viable seed standing at harvest. “What we’ve achieved this year is a useful snapshot, but we’ll need a lot more growers to take part to build a really valuable dataset,” notes Will.

And that’s the plan for harvest this year. It revolves around the Seed Circle – 140 farmers, scientists and others who have registered interest in the trial and are kept actively involved.

“Feedback from the group has indicated they’re keen to do their own on-farm trials, so we’ve developed the protocol into a simple procedure any farmer can apply just before harvesting their crop. The Seed Scouts who sign up will receive a full sampling pack with instructions that will give them an accurate picture of how much seed has been shed to help them plan subsequent control.”The value of sampling has wider implications, he adds. “It’ll build into a rich dataset, across crops, locations and grassweeds, on the efficacy of HWSC. This is data we simply don’t have at present in UK conditions.

“The more farmers who get involved, the more we’ll understand about the efficacy of HWSC and its potential to open a new, completely chemical-free window on keeping the trickiest of grassweeds under control,” concludes Will.

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