Modifying Soil Chemistry to Enhance Heathland Recreation: A Use for Sulphur Captured During Oil Refining

The overall aim of this paper is to evaluate potential new modifications to methods for re-creating heathland habitats. Heathlands need acidic soils so the specific objectives are to evaluate the effectiveness of a new method for heathland re-creation by soil acidification using a sulphur soil amendment and to explore the benefits for re-creation of applying a soil stripping treatment in conjunction with soil acidification. A new source of sulphur was recovered from oil refinery towers and applied over agricultural sites covering a total of 13 ha on Trehill Farm, Marloes, Pembrokeshire, Wales, UK in 2004. In the summer of 2011 we compared soil chemistry and plant communities on sites subjected to different sulphur treatments (sulphur applied to the existing soil surface and sulphur applied after top soil had been stripped) with those on an adjacent untreated control and on a nearby established heathland. Each of the four treatment sites and the control and heath site was surveyed using 10 random locations measuring 4 m x 4 m. The total above ground % cover was measured for each plant species and a bulk soil sample was taken in a ‘W’ shape from within each 4 m x 4 m quadrat. pH and all chemical parameters of the soil showed highly significant differences amongst the sampled sites (P>0.01 in all cases) and produced even greater abundance of ericaceous species on some of the treated sites than occurred in the established heath. However, soil stripping had no significant additional effect on either edaphic factors or plant species abundances. Sulphur recovered from oil refinery is a potentially useful tool in heathland re-creation, but soil stripping prior to sulphur amendment did not enhance success. We propose that sulphur application drives success through increasing H+ toxicity reducing the availability of base cations and creating Fe-induced Mn deficiency in plants.