The reaction, exchangeable calcium, and “lime requirement” of certain Scottish soils

Abstract

1. Of a large number of cultivated soils examined, chiefly from the south-east of Scotland, the majority had a pH between 5 and 6·5, a “lime requirement” of 0·05 to 0·25 per cent. CaCO3 and an exchangeable calcium content of 0·1 per cent, to 0·45 per cent. CaO.2. A general agreement was observed between these three sets of figures although numerous exceptions occurred.3. The reaction of a district of six square miles was studied in detail and of a single farm in still greater detail.4. Long unploughed soils were found to have a low pH, a low content of exchangeable calcium and a high “lime requirement.”5. Woodland, hill and heath soils were characterised in their surface layers by an extremely low pH (below 5 as a rule), a low content of exchangeable calcium (usually less than 0·1 per cent. CaO) and a high “lime requirement.”