Total copper contents of Scottish soils

The distribution of the total copper contents of 4179 samples from 946 Scottish soil profiles is reported and the relation of copper content to some other soil variables is examined. The frequency distribution of copper contents is found to be approximately lognormal. The derived mean for the full set of data is 10 mg/kg and the normal range 0.93–110 mg/kg. The copper contents of basic and intermediate igneous rocks exceed those of acidic rocks by a factor of about 5 and among sedimentary rocks copper contents are higher in argillaceous than in arenaceous types. The general trend is for copper to increase with increasing depth and ash content and to decrease with increasing sand content. On the basis of total copper content the risk of copper deficiency is assessed to be high in 26 soil associations in Scotland and moderate in a further 10. Naturally occurring copper toxicity is unlikely to be encountered.