Indication of S and N Inputs by Means of Needle Analyses Based on the Austrian Bio-Indicator Grid

1998

S. 63-69

7 Abb., 3 Tab., 29 Lit. Ang.

Unselbständiges Werk

200101969

The evaluation of the investigation results is based on the data from the Austrian Bio-Indicator Grid, an all-Austrian monitoring programme which, since 1983, has included annual collection of needle samples from 611 sample plots (spruce and pine) and determination of the S, N, P, K, Ca, and Mg concentrations. Althrough impacts of large-scale sulphur pollution from Austrian emitters have decreased in recent years no overall decreasing trend exists for Austria because, due to S imports, recent years have seen increasing sulphur concentrations, particularly in needle samples collected near the Slovenian and Hungarian borders. The most significant impacts of S pollution were observed at altitudes under 800 m a.s.l. In Austria, nitrogen is the nutrient element with which the investigatrd conifers are most poorly supplied. Since 1983, nitrogen supply has deteriorated and the temperoal development of results does not indicate an improvement or eutrophication. The nitrogen supply proved to be best at low altitudes (up to 600 m a.s.l.). Apart from absolute nutrient concentrations, which are of significance for the evalutation of the nutrient supply, nutrient ratios play also an important role. The highest percentage shares of plots above the harmonious ranges for N/P, N/K, and N/Mg ratios were observed in main growth regions 4, 7, and 9 (Nördliche Randalpen, Nördliches Alpenvorland, Mühl- und Waldviertel). This means that, in case of additional N input through air pollution, these regions would be subject to the greatest risk in connection with inharmonious nutrient supply.