Soil improving role of the silver fir (Abies Alba Mill.): A case study

The presented study is aimed at documenting the effects of the silver fir (Abies alba Mill.) on the upper soil status in the 86-88-year-old mixed spruce-fir stands. In autumn 2014 the samples of individual horizons (L+F1, F2+H, Ah) were taken in four replications for each species in the locations where Norway spruce and silver fir occurred in non-mixed groups. Attention was paid to the humus accumulation of holorganic horizons and their basic chemical characteristics, and to the uppermost organo-mineral horizon (Ah). Compared to the Norway spruce (Picea abies /L./ Karst.), the accumulation of the surface humus (L+F+H) was considerably lower (39.6 t.ha-1 compared to 73.7 t.ha-1), pedochemical characteristics of particular horizons did not substantially differ in both species. A slightly more favorable conditions were documented under the fir. The total nitrogen content was insignificantly higher under the silver fir, indicating richer litter and a better process of humification. The total nutrient contents of nitrogen and calcium was higher under the silver fir, the magnesium content under the spruce. Thus we can conclude that the silver fir of the above mentioned locality does not play any significant chemical soil improving role compared with the Norway spruce.