Critical loads for soils in Norway. Preliminary assessment based on data from 9 calibrated catchments

Abstract

Critical load for acid deposition with respect to soils are calculated for 9 calibrated catchments in southern Norway. Two methods recommended by the UN-ECE Handbook on Mapping Critical Loads were used: The stratic empirical model, and the dynamic MAGIC model. The critical load for soils follow two criteria: runoff water must have alkalinity > 0 (fish criterion), and the Al/Ca equivalent ratio in soil solution < 1.5 (forest criterion). The results show that for these Norwegian sites with thin and patchy soils, the fish criterion is always the more strigent. Further work should evaluate regional soils data and assess the future role of nitrogen.