The exchangeable bases in some Scottish soils

Abstract

1. The exchangeable Fe, Al, Ca, Mg, K, Na have been determined in twenty soils from different parts of the East of Scotland, by extraction with N NH4Cl solution. Data on pH, “Lime Requirement” and loss on ignition are given for the sake of comparison.2. Only three soils were found to contain Fe and Al in exchangeable form.3. The content of exchangeable bases varies from 5·6 to 22·2 milligram-equivalents per 100 gm. air-dried soil.4. The evidence is insufficient to deduce any definite relationship between pH and “Lime Requirement” and the pH cannot be correlated with the content of exchangeable bases except in the case of soils similar in character.5. It is suggested that the differences in the relative proportions of the exchangeable bases indicate that there are on the one hand fundamental differences due to soil type and on the other hand fluctuating differences due to manurial treatment.6. Emphasis is laid on the fact that the degree of saturation of a soil is not necessarily indicated by the content of exchangeable bases. At present the absorptive capacities of the soils examined are not known.7. Until a sufficient number of soils have been examined and classified, it is unlikely that any satisfactory generalisation on the subject of exchangeable bases will be forthcoming.