EVIDENCE FROM CHEMICAL-CHANGES IN INCUBATED SOILS FOR EFFECTS OF SEA-SALT DEPOSITION ON SCOTTISH UPLAND SOILS

Evidence in the literature supporting the hypothesis that inputs of se a salts from the atmosphere increase soil pH and exchangeable Na+ and Mg2+ concentrations in soils in which the release of base cations by m ineral weathering is slow is briefly reviewed. It is postulated that i f a sea salt effect indeed occurs, long-term incubation of such soils in a field moist state should result in a decline in soil pH and in th e relative importance of exchangeable Na+ and Mg2+ on the cation excha nge sites. The postulate is confirmed by examining changes in pH and b ase cation ratios in soils incubated over 3 months at 4 degrees C or a t room temperature or for 20 months at ambient outdoor temperatures in Aberdeen. The results obtained during the shorter incubation period s upport the hypothesis. However, the soil changes observed after 20 mon ths of incubation are more variable, and interpretation is complicated by the high degree of oxidation of organic C observed.