Soils and Their Related Plant Communities on the Dalradian Limestone of Some Sites in Central Perthshire, Scotland

Abstract

(1) The characteristic soils and plant communities developed on Dalradian limestone at particular locations in central Perthshire were studied. Representative sites were selected from field data collected in the course of a soil and vegetation survey. (2) For the free-draining soils there is a succession of development corresponding to a progressive increase in leaching. Soil formation is determined by the degree to which the local influence of parent material has countered the regional influence of climate. (3) Soils developed on limestone rock in situ are assigned to the brown rendzina sub-group. Their characteristic properties include an A/C or AR profile sequence, coarse texture and a well-developed crumb structure. Although surface horizons are slightly leached, the soils have high base saturation. Shallow brown calcareous soils, which have an incipient B horizon, comprise another subgroup. Both rendzinas and brown calcareous soils are very rare in central Perthshire. (4) Deeper soils developed on the mixed schist-limestone glacial drift are brown forest soils with free drainage. They display a wide range of base status; high (>50%) and low (<50%) categories are recognized. (5) The rendzinas and shallow brown calcareous soils support mainly the PolygonoHelictotrichetum pratensis association whereas the leached brown forest soils are colonized by either the Galium verum-Koeleria cristata community or the AchilleoFestucetum tennifoliae association. (6) Gley soils close to limestone outcrops are flushed by lime-rich water and have high surface pH and base saturation. They support different mire communities.