Modeling effects of changing deposition And forestry on nitrogen fluxes in a northern river basin

摘要

The application of a new, spatial nitrogen leaching/retention model N_EXRET to the Oulujoki river basin (22800 km{sup}2) in Finland is discussed. The model utilizes remote sensing-based land use and forest classification and evaluated export coefficients obtained from detailed small catchment studies. The present and future N depositions were estimated with the regional deposition model DAIQUIRI. Based on source apportionment, N deposition, forestry and agriculture each contribute 16-17% of the total export, with pronounced variation between the different sub-basins. The effect of changing forestry and deposition on N fluxes is assessed by using N deposition scenarios based on recent international emission reduction agreements.