Soils in mountain and upland regions of southwestern Norway nitrogen leaching and critical loads

Abstract

Soil data were collected from 36 points in mountain and upland areas of southwestern Norway. Samling was at cross-points on the NIJOS`9x9 km grid used for forest and soil monitoring. The soils were linked to water chemistry and deposition data from the Norwegian critical load database (12x12 km grid). Together the data were tested for relationships between N deposition, C/N ratio in soil, and NO3 concentrations in surface waters. The absence of significant relationships was ascribed to soil heterogeneity and the cource-scale of the samling. Critical loads for soils were calculated using the MAGIC model and the criterion that Ca/Al molar ratio in soil solution does not exceed 1.0. Critical loads were lowest for sites somewhat inland. With full implementation of the Gothenburg protocol by 2010, and assuming no increase in % N leached, only at a few of the sites will the critical load for soils continue to be exceeded in the long run.