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In this two year field lab Diarmid Baird, an organic farmer near Dundee, will trial his purpose-built prototype crimper roller to control bracken on his farm and monitor the environmental impacts.
The project compliments and adds value to the field lab exploring nonchemical management of bracken with livestock. This additional aspect explores an innovative mechanical option that could have applications across agricultural, forestry and conservation land. Discussion and knowledge exchange will be done collaboratively with both groups. Robin Pakeman of James Hutton Institute will carry out the researcher role for both field labs, and Tabitha Acton of the Soil Association will coordinate both trials.
Diarmid’s development of his crimping roller has gathered support from industry stakeholders including The Bracken Control group and Forestry Scotland.
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Bracken can have a major impact on farming businesses, and can be a considerable burden across the managed national landscapes. Left unmanaged, bracken can spread across grazing land and outcompete important ground flora. However, bracken is also a valuable habitat for invertebrates, reptiles, small mammals and some moorland birds. Therefore, part of the work seeks to understand how management affects biodiversity on the site.
Methods of bracken control are varied and include cutting, pulling, rolling and grazing or broadcast feeding for trampling. Many farmers also used a Asulox which until recently was approved annually as part of an emergency authorisation process for use in bracken control. Asulox posed potential risks to the environment and human health, and is no longer available.
The proposed field lab is to use a purpose-built crimper roller as a mechanical method of control. The method of crimping works by pressing a blunt metal blade along the length of the stem of the plant without cutting it. This damages the vascular system of the plant essentially 'bleeding' and slowly dehydrating it.
Following the same survey protocol as the current Bracken Field Lab [insert link], environmental outcomes of this management method will be analysed compared to a control site. This will provide additional data/comparisons for the ongoing field lab as well as providing insight into the impact and effectiveness of this innovative management technique.
The tractor and crimper will be used on a south facing slope. The machine will make around 10 passes on a small slope around 100m long and 3m wide.
Bracken measurement: The bracken growth/ regrowth will be monitored using fixed point photography and drone footage. Bracken height and density (stems within a quadrat) will also be measured.
Biodiversity surveys will be carried out to record the vegetation present within a quadrat.
Soil: Soil structure will be assessed using VESS (Visual Evaluation of Soil Structure) at both the treatment and control sites. Soil samples will be carried out and analysed using NRM Carbon check plus.
Management cost/benefit: Diarmid will monitor and assess the practical and time implications of the using the crimping roller.
This field lab is all about trialling a crimper roller which was designed to terminate cover crops in American organic systems. Diarmid Baird thought it might do a good job with bracken, which it turns out it does...!
This grass area was first rolled with a front press for a drill four years ago, single pass. In subsequent years, it was rolled with a crimper roller with an ordinary tractor, followed by a crimper with crawler tractor without additional weights. This June, the area was rolled again using a crawler with weights, and the hydraulics set to neutral.
You can see drone footage of the treated area in this video, taken by Diarmid.
Photos were taken at the end of September 2025, and reflect current field conditions. Photo credit: Diarmid Baird, Farmer (2025)
In this video you can see the strip which was crimped one month later than the strip in the photograph above and achieved a more complete kill compared to the June treatment.
Close-up images of the ground show the crimper roller’s action: it bruises but does not sever the stems, approximately every 100mm. This technique promotes the breakdown of bracken litter and supports the regrowth of grasses. Wildflowers have also begun to emerge in the treated areas.
All photos were taken at the end of September 2025, and reflect current field conditions. Photo credit: Diarmid Baird, Farmer (2025)
June 2025
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Winter 2026/27
Soil Association
Northumberland
Tabitha joined the Soil Association from previous roles within the NFU as county advisor for Northumberland and AHDB as a Knowledge Exchange Manager within the Farm Economics and Beef and Lamb teams covering the North of England. This experience sits alongside farming at home with her partner on a hill farm in Northumberland producing pedigree sheep and cattle.
Tabitha’s academic background lies within the human health sector with a BSc Hons in Biomedicine and Nutrition and a MRes in Immunobiology from Newcastle University. Tabitha’s main focus is on the practical application of research within the farming sector and supporting businesses to be in the best position moving forward.
James Hutton Institute
NE Scotland
