About the influence of the fertilizing intensity on the N-cycle of alpine grassland

By means of a long termed field experiment, carried out at the BAL Gumpenstein, different aspects of the nitrogen balance and their importance for grassland management have been worked on. The linear course of the curve for the nitrogen saldo within the observed fertilizing intensity from 0 to 240 kg N ha(-1) year(-1) showed a well balanced result at a fertilizing level up to about 150 kg N ha(-1) year(-1). Displacement of legumes was significantly stronger by nitrogen from mineral fertilizers than by nitrogen from farm manure. A comparison between mineral fertilized NPK treatments with the fertilizing systems "slurry" and "stable manure + liquid slurry" at an adjusted N-level showed a better efficience and advantage of the farm manure systems, increasing with the time of experiment.