Long-term behaviour of 15N in an alpine grassland ecosystem
- Cite this article as:
- Gerzabek, M.H., Haberhauer, G., Stemmer, M. et al. Biogeochemistry (2004) 70: 59. doi:10.1023/B:BIOG.0000049336.84556.62
Nitrogen dynamics in semi-natural environments is crucial for the development and ecological stability of these systems. The present paper shows the results of the reinvestigation of a 15N-tracer experiment, which was established in the Grossglockner massif in Austria at 2300 m a.s.l. in 1974/1975. We show that large quantities of nitrogen introduced by a single pulse labelling (amounting to approximately 1.7% of the nitrogen in the system) into an alpine grassland remain in the soil–plant system, with only 55% being lost during 27–28 years. In the first 10 cm of the four investigated soil profiles 40% of 15N was recovered, being mainly bound in organic forms. A simple site specific model was established on the basis of the results considering a biological, residual and labile N-pool, the latter being the source for N-losses. By the model a long mean residence time close to 100 years was derived for the remaining 15N.