Critical loads for soil in Norway, Nordmoen

Abstract

We evaluate the critical load for soil and water at Nordmoen using the dynamic model Magic, the static PROFILE model, and the empirical method as suggested by the mapping handbook. Nordmoen is located about 60 km N of Oslo on thick deposits of glaciofluvial sands, and receives moderate (for Norway) levels of acid deposition (53 meqSO4/m²/yr). At Nordmoen both acid deposition and forestry practices have caused soil acidification. MOGIC indicates that the "tolerable" load is 0 meq SO4/m²/yr under the conditions that the CA/AL molar ratio in soil solution be above 1 or 0.5. The estimate assumes that forestry practices will continue for the next 50 years. The empirical method for waters gives a critical load estimate of 126 meq SO4/m²/yr. Nordmoen is thus a site in Norway at which the soil and forest are more sensitive than surface waters. These results can be used to determinate under which circumstances forest will be more sensitive than fish, and thus provide a basis for mapping critical load.