The Sports Turf Research Institute - Showcase

Path Trials for English Heritage

English Heritage, who are the government’s advisor on the historic environment, contacted STRI to discuss concerns about wear and erosion on historic sites such as Hadrian’s Wall. The increased foot traffic at many sites was causing loss of grass cover with consequential erosion of underlying soil. In many places it would be visually inappropriate to construct gravel and stone paths; indeed such constructions would also have implications for any underlying archaeology in the vicinity of the path. Both organizations felt that the expertise of STRI is maintaining grass cover under high stress conditions on sports fields could be usefully carried across to the management of grass paths on historic sites.

Scientific Study

As a follow up to these discussions English Heritage commissioned STRI to carry out some research on turf protection/stabilisation systems that would be suitable for general use on their sites.  This led, in the summer of 2004, to a fully replicated scientific trial at STRI’s trial ground in West Yorkshire using an established mixed grass turf growing on a sandy loam soil. The main categories of materials tested were

1. Surface loose topdressing material, e.g. sand. The aim of these was to protect the growing point of the grass from foot traffic.
   
2. Surface, plastic grid protection systems. These lift the abrasive effects of foot traffic off the turf surface itself.
   
3. Sub-surface installed soil stabilisation/turf protection systems. The grid/honeycomb structure of such systems prevent soil lateral movement as well as reducing abrasion of the grass by foot traffic.
   
4. Fertiliser – All of the physical amendments in (1), (2) and (3) were treated in a factorial manner with three rates of a controlled release fertiliser product.

The whole trial area was mown at 20 to 30 mm cutting height. In addition it was subjected to pedestrian – type wear using one of the STRI’s wear machines. The trial ran for a full year.

The results showed that, during the summer months, the application of the controlled release fertiliser had a dominant effect on wear tolerance of the turf. In essence the turf was being helped to ‘grow through’ any surface abrasion and compaction damage.

However, with the onset of autumn, cooler temperatures, shorter day lengths and wet soil conditions reduced the growth rate of the turf, even with fertiliser application. It was at this point that the plastic surface protection systems came into their own. By keeping the surface traffic off the growth points of the turf they were able to prevent actual death of the grass plants. Moreover, there was some prevention of the surface soil compaction that would occur under the wet weather conditions.

The loose surface topdressing materials had little impact on wear tolerance of the turf. This is somewhat surprising as sandy topdressing materials applied to football pitches can have a major positive effect on the grass cover during the winter playing season.

The sub-surface products also had little impact on the ability of the turf to withstand wear. This may have been due to the fact that only a minimal depth of the grids protruded above the turf surface. Thus protection to the grass itself was insignificant.

On Site

The results of the trial at STRI are now being taken to a number of English Heritage sites around the country, from Hadrian’s Wall in the north to St. Augustine’s Abbey near Canterbury Cathedral in the south

The materials, which appeared to be most effective in maintaining grass cover, are being tested. These are being installed in plots within well-used paths on the EH sites; the numbers of visitors using the paths are being monitored.

These trials will continue until spring 2007 with, hopefully, the development of more exact guidance for the most appropriate system for any particular site.

The results of the trials are likely to be of interest to anyone involved with path & maintenance. In particular Countryside Access Offices of County Councils in England and Wales may find the results to be of particular relevance for their Rights of Way Improvement Plans (ROWIP)

If you would like any more information on the trials please contact David Lawson at STRI.   

Contact David Lawson