Are you 100 per cent committed to ridding your farm of black-grass? Dominic Kilburn spoke to an arable farming couple that is dedicated to the cause.
Having a zero tolerance approach to black-grass control is a strategy that has been attributed to many over the past few years, as growers and agronomists alike have battled to keep the pernicious weed at bay using a mix of cultural and chemical controls on farms up and down the country.
However there can be few who live up to the zero tolerance approach of arable farmers Rob and Mary Smithson, whose attention to detail in their approach to black-grass control is not only admirable, in terms of the hours they both dedicate to the cause, but also critical for the sustainability of their high quality seed growing business.
Fretwell Farm, Beckingham is on the Nottinghamshire/Lincolnshire border close to Gainsborough. Of the 600ha farmed, typically 240–300ha are dedicated to growing first and second wheat seed each season.
In addition, oilseed rape makes up the rotation.
Rob has been growing wheat for seed for the past 45 years and so the farm’s philosophy is geared to producing clean, weed-free crops. “We’ve always grown seed here but with that comes the increased challenge and responsibility to ensure that what we produce is of the highest quality and free from all weed seeds,” says Rob.
“Failing to achieve that, then we wouldn’t command the premium we receive over the commercial market,” he adds.
Rob reckons that about 10 years ago he started to notice black-grass creeping into fields on the farm for the first time and, during the following seasons, it began to impact on the business. “We can’t be sure how it got onto the farm in the first place but in all likelihood some of it was from winter wheat seed that we were supplied, and so that gives us an extra incentive to ensure the seed crops we produce are 100 per cent free of black-grass seed.”
With black-grass testing positive for resistance, Rob initially took to spraying off large acreages with glyphosate where crops were infested, but then a strategy of spot spraying (by Rob with a knapsack) followed by hand rogueing (by Mary) was developed in tandem with more traditional methods of control.
“Our agronomist, Graham Chester, works closely with us and advises that a stacked herbicide programme at the start of the season is vital to get good, early control of black-grass in autumn-sown crops,” explains Mary.
“The problem is that those plants that escape this treatment are the most resistant to chemistry, and it is imperative for weed reduction that they are removed later in the spring by a knapsack sprayer-targeted glyphosate application.
“Any remaining after that are hand rogued,” she adds.
From May through to July, Mary typically spends up to 200 hours rogueing black-grass plants in winter wheat crops, often returning to the same field up to 3 times to achieve their goal of total black-grass elimination.
Ordinarily this is no mean feat, but considering Mary holds a full-time job as a branch office manager for a firm of solicitors in Epworth, 10 miles north of the farm, her determination to succeed with this strategy is even more remarkable.
“During the summer we both start in the fields at 5am; Rob with the knapsack sprayer and me hand rogueing, and then at around 7.45am I have to leave, return to the house, shower, change and set off for work in Epworth,” comments Mary.
“Later in the evening, from 7–10pm, I’m back in the fields again,” she adds, pointing out that clocking up a 17-hour day is not unusual at that time of the year.
Mary says that while cultural controls such as delayed drilling and stale seedbeds, as well as herbicides, are reducing black-grass numbers each year there are limitations on the use of glyphosate as a seed producer. “The early knapsack spraying and rogueing policy is therefore key, especially if regulations tighten on the use of glyphosate in the future,” she comments.
“Two years ago I spent 27 hours rogueing in one wheat field alone. The field was followed by OSR in 2018 – a crop well-known for harbouring and nurturing black-grass – and this year it returned to wheat, however there was not a sign of black-grass in that crop,” she explains.
“The reward for all the hard work is looking over clean crops and realising that the weed burden is depleting each year,” Mary says.
Rob adds: “For harvests 2018 and 2019 we have put less than 1 per cent of the black-grass we started with – a target judged by not actually finding any plants in the crop – through the combine. In fact, our combine operator reckons he never sees a plant.”
AICC Yorkshire Arable Advice agronomist, Andrew Fisher, inspects seed grown on Fretwell Farm for distributors each season and he is impressed by the results Rob and Mary have achieved with their approach to black-grass control. “They have made super-human efforts to get on top of the black-grass situation across the whole farm, and especially in the seed crops.
“On most farms where I inspect seed crops there’s always some areas for improvement in terms of black-grass control, and the continued loss of chemical actives means that the answer cannot be found in a can,” comments Andrew. “Rotation, cultivations, competitive varieties and, ultimately, rogueing – especially the surviving plants from a herbicide programme – is the only way to successfully tackle the issue.
“Rob and Mary ensure that the quality of the seed which leaves their farm is of the highest standard and other growers can learn from their dedication,” he concludes.