ABSTRACT
In ombrotrophic peatland ecosystems, precipitation is the main source of nutrients for the vegetation and their contents of essential nutrients, such as phosphorus (P) and of nitrogen (N), are low compared with other soils. Evidently, many factors determine the fate of N that reaches the bog surface. This chapter considers the information available on the fate of N added to peat soils and present some experimental results of the effects that N additions have on the size and activity of the microbial biomass. In the absence of plant uptake, atmospheric N is more likely to penetrate the vegetation canopy and reach the litter and peat horizons, provided hydrological conditions do not favor losses in surface runoff. Depending on the molecular size and chemical nature of the N, the soluble organic N pool may simply be a product of rapid assimilation of inorganic N into the microbial biomass and a form of temporary immobilization.
