SULFATE ADSORPTION CAPACITY AND PH OF UPLAND PODZOLIC SOILS IN SCOTLAND - EFFECTS OF PARENT MATERIAL, TEXTURE AND PRECIPITATION CHEMISTRY

A regional survey of podzol B horizons has been carried out to investigate the effects of parent material and soil texture on sulphate (SO4(2-)) adsorption capacity and pH in Scottish soils. Sulphate adsorption was measured on equilibration of the soils with 10 and 100 mg l-1 SO4(2-) solutions. The results showed that soil texture and soil parent material had a significant effect on SO4(2-) adsorption. Significant correlations were found between sulphur (S) deposition loads and SO4(2-) adsorption, and between precipitation pH and soil pH, but not between total hydrogen ion (H+) load and soil pH, even on sensitive soils. Relationships between the chemical composition of atmospheric deposition and soil pH could be marginally improved if the possible amelioration of acidification by base cation inputs, especially on sensitive soils, was taken into account.