%0 Research article
%T Temporal trends in chemical parameters of upland forest soils in southern Finland
%A Tamminen, Pekka
%A Derome, John
%D 2005
%J Silva Fennica
%V 39
%N 3
%R doi:10.14214/sf.370
%U https://silvafennica.fi/article/370
%X Changes in chemical soil properties during periods of 12 to 28 years  were studied in 54 stands in southern Finland. Relative slopes (%/year)  were calculated for the changes in soil variables in order to utilise  all the sampling occasions (2–6) covered by the study period. Only the  results of new analyses made on the soil samples could be used owing to  unpredictable differences between the results of the original and new  analyses. During the study period the acidity (pH, exchangeable acidity)  of the organic layer had decreased, and the mineral soil had become  more acidic only in terms of increased exchangeable aluminium  concentrations. An increasing trend in the amount of soil organic matter  best explained the acidity variables: it lowered acidity in the organic  layer, but increased it in the mineral soil. Acid ammonium acetate  extractable nutrients showed decreasing trends over time, apart from an  increasing trend for sulphur in the 0–30 cm mineral soil layer. Total  concentrations of most elements in the organic layer, including nitrogen  and sulphur, also showed a decreasing trend. Changes in the soil  variables could not be firmly connected to deposition, wood production  or the amount of nutrients accumulated in woody tissues. However, the  decrease in sulphur concentrations in the organic layer was clearly  linked with the decrease in sulphur deposition in recent years.