title: Investigations of nitrogen fluxes and pools on a limestone site in the Alps.
abstract: In the North Tyrolean Limestone Alps a site was investigated over a four-year period (1998-2001) in order to assess the nitrogen saturation status, the nitrogen budget (quantification of the net uptake of nitrogen by the canopy and of the nitrogen mineralization, nitrogen uptake from roots and N2O emission rates, proof of the origin of nitrate in the soil water with stable isotope analyses), and the effects of the actual nitrogen input on ground water quality. The main goals were to quantify the nitrogen input rate, the nitrogen pools in above-ground and below-ground compartments, nitrogen turnover processes in the soil as well as the output into the groundwater and into the atmosphere. The findings are based on continuous and discontinuous field measurements as well as on model results. While nitrogen input exceeded the Critical Loads of the WHO (1995), nitrogen deficiency and nutrient imbalances were verified by needle analyses. The atmospheric input of inorganic nitrogen was higher than the nitrogen output in 50 cm soil depth. A tracer experiment with 15N helped to prove that not more than half of the applied nitrate could be discharged. This allows the conclusion that nitrogen is stored in the system and that the site cannot yet be said to be saturated with nitrogen. The same result was also obtained by modelling. In addition, it was proved that the nitrogen discharge did not stem from deposition but from processes within the system.
authors.affiliation: Institut für Immissionsforschung und Forstchemie, Forstliche Bundesversuchsanstalt, Vienna, Austria. friedl.herman@fbva.bmlf.gv.at
authors.forename: Friedl
authors.initials: F
authors.lastname: Herman
authors.forename: Stefan
authors.initials: S
authors.lastname: Smidt
authors.forename: Michael
authors.initials: M
authors.lastname: Englisch
authors.forename: Franz
authors.initials: F
authors.lastname: Feichtinger
authors.forename: Martin
authors.initials: M
authors.lastname: Gerzabek
authors.forename: Georg
authors.initials: G
authors.lastname: Haberhauer
authors.forename: Robert
authors.initials: R
authors.lastname: Jandl
authors.forename: Michael
authors.initials: M
authors.lastname: Kalina
authors.forename: Sophie
authors.initials: S
authors.lastname: Zechmeister-Boltenstern
mesh_terms: D000531:Altitude; D001317:Austria; D002119:Calcium Carbonate / Q000737:chemistry*; D004784:Environmental Monitoring; D008962:Models, Theoretical; D009566:Nitrates / Q000032:analysis*; D009584:Nitrogen / Q000032:analysis* / Q000737:chemistry; D009609:Nitrous Oxide / Q000032:analysis; D012987:Soil; D012989:Soil Pollutants / Q000032:analysis; D014867:Water / Q000737:chemistry; D014873:Water Pollutants / Q000032:analysis
chemical_list: D009566:Nitrates; D012987:Soil; D012989:Soil Pollutants; D014873:Water Pollutants; D014867:Water; D002119:Calcium Carbonate; D009609:Nitrous Oxide; D009584:Nitrogen