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 resto re heathland and acid grassland on 158 ha of ex-arable land at their Minsme re reserve; the aims being to join existing small heathland fragments toget her and provide habitat for the conservation of three rare birds - the ston e curlew (Burhinus oedicnemus) the woodlark (Lullula arborea) and the night jar (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 sug gested that soil acidification will be needed to ensure successful heathlan d establishment. This paper reports the results of an experiment where elem ental S (0-12 t S ha(-1)) has been added to acidify these ex-arable soils i n factorial combination with Calluna seed added in cut shoots. The effects of these treatments on the establishment of(a) Calluna, (b) ruder al specie s and (c) plant communities were assessed. The main result is that the cove r of the ruderal species was significantly reduced where the soils had been acidified, which should help Calluna to establish. However, Calluna establ ishment was relatively poor, mainly because of inadequate weed control in t he early phases, but seedlings were most abundant where S was applied at be tween 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 contr ol is essential at the time of adding the Calluna seed. (C) 2000 Elsevier S cience Ltd. All rights reserved.