Investigations of nitrogen fluxes and pools on a limestone site in the Alps.

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.

Water and nitrate fluxes at a forest site in the North Tyrolean Limestone Alps.

The water balance for the site Mühleggerköpfl in the North Tyrolean Limestone Alps has been established to a soil depth of 50 cm. The evaporation amounts to 42% and deep percolation is 58% of the precipitation. The surface runoff was negligible and therefore the according nitrate fluxes as welL Soil water analysis revealed mean nitrate concentrations of 3 to 15 mg NO3 L(-1), depending on soil depth.