Creation of heathland on former arable land at Minsmere, Suffolk, UK:: the effects of soil acidification on the establishment of Calluna and ruderal species

The Royal Society for the Protection of Birds (RSPB) is attempting to restore heathland and acid grassland on 158 ha of ex-arable land at their Minsmere reserve; the aims being to join existing small heathland fragments together and provide habitat for the conservation of three rare birds - the stone curlew (Burhinus oedicnemus) the woodlark (Lullula arborea) and the nightjar (Caprimulgus europaeus). The ex-arable soils have been shown to have a higher pH (pH > 6) than the adjacent heaths (pH 3.5-4), and it has been suggested that soil acidification will be needed to ensure successful heathland establishment. This paper reports the results of an experiment where elemental S (0-12 t S ha(-1)) has been added to acidify these ex-arable soils in factorial combination with Calluna seed added in cut shoots. The effects of these treatments on the establishment of(a) Calluna, (b) ruder al species and (c) plant communities were assessed. The main result is that the cover of the ruderal species was significantly reduced where the soils had been acidified, which should help Calluna to establish. However, Calluna establishment was relatively poor, mainly because of inadequate weed control in the early phases, but seedlings were most abundant where S was applied at between 1 and 4 t S ha(-1). We tentatively suggest that the most appropriate treatment is to apply 4 t S ha(-1), a rate that gives acidification to the appropriate range and maintains good control of ruderal species. Weed control is essential at the time of adding the Calluna seed. (C) 2000 Elsevier Science Ltd. All rights reserved.