Nutrient Contents of Spruce Needles from the Tyrolean Limestone Alps

Summary STEFAN K. & HERMAN F. 1996. Nutrient contents of spruce needles from the Tyrolean Limestone Alps.-Phyton (Horn, Austria) 36 (4): 231 - 244. The nutrient concentrations in the needle samples of the Bio-Indicator Grid were used to evaluate the nutrient situation in the Northern Tyrolean Limestone Alps. The poor nitrogen supply, which was proved in the framework of the Austrian Bio-Indicator Grid, was found also in the Tyrolean Limestone Alps. In addition, a marked deterioration of the nutrient situation was observed during the period under investigation (1983-1992). It is assumed that the weather played an important part in this unfavourable development (lack of precipitation and significantly higher temperatures during the vegetation periods, particularly in 1992). The concentrations of phosphorus and potassium remained approximately the same; the calcium content increased. The most frequent types of deficencies were nitrogen, phosphorus, and NP deficiencies. In 1992, a marked decrease in the magnesium concentrations was found. Generally, the altitudinal zone between 1000 m and 1200 m showed the worst nutrient situation, which can also be seen from the fact that, during the last five years of investigation , samples from that zone had the lowest concentrations of N, P and Mg. . So the nitrogen nutritiant situations of the needles of the area of Achenkirch was poor from the very beginning, it was not possible to show the significant deterioation of the situation of the Tyrolean Limestone Alps in the area of Achenkirch. A remarkable improvement of the nutrient situation was observed at the high-altitude sub-alpine sample plot (Schulterberg). As opposed to the results from the Limestone Alps, which did not show any significant changes regarding the supply with K and Ca during the same period, the K supply deteriorated in the area of the "Achenkich Altitude Profiles"; and the calcium supply improved remarkably. Different results were also obtained in respect of the Mg supply which, until 1990, improved in the Limestone Alps, but after that deteriorated clearly, while it remained almost at the same level in Achenkirch during the entire period. In both areas of assessment the mean P concentrations remained the same.