EVIDENCE FOR ACIDIFICATION OF SENSITIVE SCOTTISH SOILS BY ATMOSPHERICDEPOSITION

The Scottish soils most sensitive to acidification from acid depositio n are peats and those derived from quartzite or Devonian and Torridoni an sandstones. It is shown that the surface horizons of Calluna moorla nd podzols derived from these mineral parent materials behave in a sim ilar way to peats, in that their pH depends upon cation exchange equil ibria between H+ and Ca2+. The pH is therefore related, as might be ex pected from the ratio law, to the ratio [H+]:root[Ca2+], and this rela tionship may be used to predict the effect of emission reductions or i ncreases upon these soils.