Influence of simulated sulphur and nitrogen depositions on biomass and nutrient relationships of mountain ash, European beech and Norway spruce in a pot experiment with two soil substrates from the Ore Mountains

Growth and nutrient relationships of mountain ash (Sorbus aucuparia), Europ ean beech (Fagus sylvatica) and Norway spruce (Picea abies) were investigat ed in a pot experiment with the two substrates rhyolithe (acidic) and basal t (alkaline). Additionally, depositions of sulphur (S) and nitrogen (N) as expected:to occur in the Ore Mountains (Saxonia, Germany) in the future wer e simulated in order to test the species' suitability for forest regenerati on. After two years, aboveground biomass was significantly higher on basalt compared to rhyolithe for all species. The amount of S given (0 and 100 kg ha(-1) a(-1)) and the dominant form of N applied (NH4+:NO3- = 1:4 and 4:1; total amount of N given 80 kg ha(-1) a(-1)) were of minor influence only. The contents of N and K in leaves or needles were higher on rhyolithe, wher eas P, Ca, Mg and Mn contents were higher on basalt. Nutrient contents were only slightly affected by the amount of S supply and the NH4+:NO3- ratio. In contrast to mountain ash, beech saplings exhibited considerable growth o n rhyolite. It is therefore concluded that beech may be a suitable species for forest regeneration even on acidic soils suffering heavily from S and N immissions,:whereas spruce,will not tolerate high S loads. However, increa sing N depositions by stimulating growth may:cause deficiencies:Of Mg and K in both species.