Agronomy firm Hutchinsons has established a new demonstration farm on the Essex coast near Harwich - a heavy land site which has battled grassweeds for years.

While black-grass has largely been brought under control in recent years, ryegrass has now become the dominant concern, with populations surging up to 120-150 plants per square metre.

Host farmer Andrew Strachan said weed control started getting harder following the stubble burning ban in the 1990s.

“We’ve made great progress against black-grass, and have farmed around 98% of it out, but Italian ryegrass has taken over as the main issue, and is proving a lot harder to control,” he said.

This could partly be a legacy of historic land use on the farm, he added, as two fields previously grew ryegrass for seed, and several other fields were used for orchards, with grass growing around the trees.

Wheat yield in the worst-affected field has been as much as 60% below the farm average, and in that situation, land was ploughed and fallowed for a season to address the problem.

"That field is now one of the cleanest on the farm," said Mr Strachan.

Farmacy agronomist Jim Woodward (Image: Hutchinsons)

Working with Farmacy agronomist Jim Woodward, he managed the fallow with targeted cultivations and herbicide use to reduce ryegrass populations as much as possible before planting wheat the following autumn.

Rotational ploughing one year in seven remains a useful tool for managing grassweeds within the min-till system, said Mr Strachan - although, in very dry years, ryegrass can still germinate out of the cracks that develop in the silty, clay-based soil.

Trials at the Hutchinsons Ryegrass Management Farm include assessments of 25 different herbicide options, a smaller study examining the effect of three different glyphosate timings, and a field-scale trial of different cultivation and drilling techniques to asses their impact on crop establishment, ryegrass populations and seed return.

The farm is also exploring approaches including alternative cropping, clover undersowing, improving hygiene on cultivation and harvesting machinery, and drainage improvements to help crop establishment and boost competition over grassweeds.

Italian ryegrass is a growing threat for arable farmers in the East of England (Image: Hutchinsons)

"We’ve made some progress, and the worst fields are getting better, but at the moment, there’s still always some level of seed return, so it’s a question of what’s acceptable," said Mr Strachan.

ADAS weed science consultant John Cussans said Italian ryegrass was previously a relatively localised problem in a few hotspots areas, but is now becoming more widespread across much of the UK.

“Sometimes it is because of an historic legacy, but other times that’s not the case, and it can be hard to pinpoint exactly where issues have come from," he said.

He added that ryegrass is a “very different beast” to black-grass for several reasons, including its protracted germination periods, aggressive and competitive plants, high seed return, drought tolerance and a tendency to develop resistance to herbicides.

Testing by ADAS as part of the Hutchinsons trials shows herbicide-resistant populations are present at the Harwich demonstration farm.

Hutchinsons development manager Jennie Watson said: "With new chemistry available, there are still plenty of effective options for controlling ryegrass, but the challenge is often the cost-effectiveness of some of these, so we have to consider how they can be best used alongside other cultural controls.

“That is all part of the work we’re doing here at Harwich.”

The Hutchinsons Ryegrass Management Farm on the Essex coast, near Harwich (Image: Hutchinsons)

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