Contrasting effects of low and high nitrogen additions on soil CO2 flux components and ectomycorrhizal fungal sporocarp production in a boreal forest
Nitrogen (N) added through atmospheric deposition or as fertilizer to boreal and temperate forests reduces both soil decomposer activity (heterotrophic respiration) and the activity of roots and mycorrhizal fungi (autotrophic respiration). However, these negative effects have been found in studies that applied relatively high levels of N, whereas the responses to ambient atmospheric N deposition r