Beating black-grass: Patience is a virtue
15.10.2024
Nigel Durdy farms 1,100ha in partnership with his brother, Adrian, near Doncaster in Yorkshire and grows winter wheat, winter rye, spring barley and vining peas.
Here, he joins ADAS Senior Research Consultant, Sarah Cook, to discuss how the recent wet weather has affected his drilling campaign and what it means for black-grass control going forwards.
Time is on our side
“Ideally, we would have started drilling at the beginning of the month, but we will just keep waiting until conditions allow us to drill,” he says.
“If that doesn’t happen, we will plant spring barley instead. But there’s a long way to go yet - 31st January is the cut-off date for winter wheat.”
Stick to your plan
One recent rainfall event saw 65mm fall in less than 48hours yet Nigel is sticking to his plan.
“Nothing changes – getting a good seedbed, drilling depth, timing of drilling and spraying – it all stays the same, no matter when we drill.”
Sarah says it is a good strategy, highlighting the need to establish a competitive crop.
“The tendency will be to drill as soon as conditions allow, it would be worthwhile holding back until conditions are optimal for establishment. If you can roll after drilling, even better.
“Mauling crops in at the earliest opportunity has long-lasting consequences – it risks poor emergence and patchy establishment – not only does this give weeds the space to take hold but makes the crop difficult to manage throughout the season,” she notes.
While acknowledging drilling depth can be more difficult to achieve when conditions are wet, Sarah says it remains important to follow pre-emergence herbicide guidelines to reduce the likelihood of crop damage.
“Residuals form a layer near the soil’s surface, the objective is to place the seed below that depth to ensure it is protected,” she explains. “High rainfall events can wash the herbicides through the soil profile, so we’re looking for a dry weather window that allows time for drilling, rolling, pre-em applications and beyond.”
Learning lessons
Nigel’s experience of last year demonstrates the importance of holding out for a window that allows pre-emergence herbicides to be applied.
“We had six fields that were drilled but didn’t get sprayed,” he says. “Four had to be destroyed in spring because the black-grass would have out-competed the cereal crop or self-seeded by harvest. In hindsight, I should have destroyed another one.”
While ‘hold tight’ is Nigel’s current mantra, he will change tact if the situation requires. In autumn 2023 he drilled the middle of one field only, because the headlands weren’t fit.
“It was frustrating,” he admits. “But it did highlight that Luximo was doing a good job, there was a significant difference in black-grass levels between the cropped area and the headland.”
Nigel develops different herbicide programmes depending on soil type, black-grass pressure and whether it is in first, second or continuous wheat.
“On this field, I wouldn’t have used anything other than Luximo because I think it is the most effective product. It’s one of the fields with high black-grass pressure and has seen flufenacet-based programmes for many years. It’s not a bad thing to change the actives from a resistance perspective too.”
Beyond chemistry
Alongside the changes Nigel has made to the herbicides he uses, he is using the SFI scheme to lengthen the time between harvest and drilling and establishing stale seedbeds.
“We’re using the summer fallow on the heavier land and the wild bird mix on the lighter land. Both will contribute to black-grass control, but like any other break crop, it needs the attention to detail you’d give to a cash crop to get the benefits for the wheat that follows.
“We are winning the war against black-grass. Shifting to breaks that allow time for stale seedbeds and delayed drilling, using new and different chemistry, timing applications, not letting black-grass shed excessive seed – it is all contributing,” he concludes.
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