The latest news from our rush management trials

Background

Located north of the Greater Manchester conurbation, but separated from the main Pennine range by the Irwell valley, the West Pennine Moors (WPM) supports a range of upland habitats and is an important site for wading bird populations (such as lapwing, curlew and redshank). Whilst a significant proportion of the WPM is in-bye farmland (approx. 20%), changes in land management and stocking regimes have caused the quality of this land to deteriorate since the 1980’s. Such deterioration not only has the potential to impact farmers and wildlife in the area, but also water quality and flow within the catchment.

Compaction of soil surface layers in the in-bye due to increased grazing pressures (for example through year-round stocking on the in-bye) reduces the ability of water to infiltrate the ground. Greater amounts of water will therefore pool on the soil surface or run-off into nearby watercourses, potentially contributing to poor water quality and greater flood risk downstream as the ground becomes less able to filter and store water. Additionally, these soil changes, alongside acidification of the land, allow soft rush (Juncus effusus) to become the dominant vegetation. Infestation of fields by rush decreases the quality of land for grazing stock and wading birds, but also impedes soil drainage, further contributing to water issues downstream. Employing effective land management methods that tackle rush infestation and soil compaction in upland regions can therefore deliver multiple benefits for farmers, local wildlife, and water in the catchment.

Rush Management Trials

By working with local landowners and farmers, Natural Course have been investigating the best practice for control of soft rush and how that impacts soil compaction. Farmers carried out different methods of rush management in various fields across their land; all fields underwent appropriately timed cutting of rush followed by a weed-wipe of the sward, with some fields also undergoing additional interventions of aeration and/or application of lime. Alongside rush management, surveys were carried out annually to assess changes in rush cover and soil compaction over time, with the last of these surveys taking place over the summer by three members of the Natural England team.

During surveys, 20 quadrats were placed across each field at set GPS co-ordinates to make sure data collected was representative of the whole field. Within each quadrat the percentage of rush cover was estimated. Variation both between and within fields quickly became evident, with some quadrats still dominated by rush whilst others with lower rush cover had become dominated by grass species. A soil compaction measurement was also taken at each quadrat by pressing a special compaction meter into the ground and recording the resistance at various soil depths. At some quadrats, a lot of force was required to get the meter into the ground, indicating high levels of compaction, whereas at other quadrats the ground was much less compact and allowed the meter to glide through the soil. This variation was further impacted by the weather; the first day of surveys took place following a series of dry, hot summer days which made the ground very tough to press the meter into (and giving one member of the team a good arm workout), whilst the second day occurred on a cold, rainy day making the surface layer of the soil less resistant. After collecting data, it was time for the team to head back to their desks and assess the findings alongside data from surveys carried out in previous years.

Preliminary findings and next steps

Initial conversations with Farmers, and observations made during surveys, suggest that each method of land management trialled has helped to reduce the levels of rush cover within a field. This is a positive sign and suggests that even basic rush management can help improve the quality of the land. Soil compaction changes were less clear though, with weather and natural variation in the ground strongly impacting readings at each quadrat. To further investigate these observations, data collected during the surveys have been statistically analysed, with a scientific report currently being produced to outline the key findings. Natural Course are also producing a leaflet providing guidance to landowners on the most effective land management method for rush control and soil compaction. This leaflet will outline the benefits of each land management method and explain how effective management can help to improve land quality for grazing stock, local wildlife and water infiltration. Whilst this work has focussed on the WPM, problems relating to rush cover and soil compaction occur across upland regions, it is therefore hoped that this guidance will aid land quality improvements in upland farmland across the UK.  We look forward to bringing you the final conclusions from these trials later in the year following the completion of this project.

West Pennine Moors Rush Trials (before and after)
Credit Natural England

For more information about this project https://naturalcourse.co.uk/projects/rush-control-trials-for-farming-biodiversity-and-run-off-reduction/