Appropriate ploughing reduces black-grass

Andrew Wilkin

Farming 800 acres of combinable crops, Yorkshire farmer Andrew Wilkin has seen black-grass populations rocket in the last two years. However, swift action to introduce appropriate ploughing and a robust herbicide programme has reduced populations from 1,500 plants/m2 to just 15 plants/m2.

“A dry autumn in 2011 followed by an extremely wet 2012 autumn and following spring threw our plans into chaos,” he explains. “But the high population attracted attention from Bayer CropScience, who thought it an ideal site to trial different cultivations and pre-em stacks.”

“Ploughing was by far the most effective cultivation method,” says Andrew. “It hadn’t been ploughed for four years, so we buried a vast seedbank to depth and brought clean soil to the surface.”

“Ploughing is not a miracle cure,” he warns. “If we were to plough next year, we would be returning soil full of black-grass back to the surface. So it has to be appropriate ploughing, coupled with a strong herbicide programme.”

Matthew Garnett, Bayer CropScience

“Soil type and weather on Andrew’s farm limit cultural controls. One of the most effective methods, spring cropping, is nearly impossible.

“When you’ve a succession of tricky seasons like 2011 and 2012 limiting the success of delayed drilling and stale seedbeds, black-grass populations can quickly get out of control. Each plant can shed up to 6,000 seeds in a season.

“But as the trial here has shown, burying seed by rotational ploughing can be highly effective, providing an average control of 69%.

“Black-grass seeds need light to germinate and once buried 70% will become un-viable every year. If you know the approximate amount of seed on the surface, as well as the amount of viable seed likely to exist lower in the soil profile, you can work out if the costs of ploughing will be worthwhile.

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