| Abstract: | Growth and mineral nutrition of beech (Fagus sylvatica) and maple (Acer platanoides) on soil, polluted by infiltration of acidic stemflow Stemflow in beech stands in areas with atmospheric pollution may become highly acidic and enriched with heavy metals due to interception of pollutants in the canopy. Over long periods soil properties in the infiltration zone of such stemflow change significantly. Soil samples from the infiltration zone of stemflow and samples from zones more distant from the trunks were collected in the Vienna Woods and used in a pot experiment to assess the influence of soil pollution on tree growth. This method was considered superior to experiments with artificial acidification, as soil changes in the infiltration zone of stemflow in old growth beech stands are the result of steady input of highly diluted pollutants over a long span of time in proportions typical to these sites. Soil analyses (table 1) showed leaching of Ca, Mg and Mn, a decrease in pH, increased Al-availability and modest Pb-enrichment. Plant growth (fig. 1) was reduced on the acidic substrate and root damage, especially dieback of root tips and brooming of new roots in beech could be observed. Mineral nutrition (fig. 2,3 and table 2) of plants on the acidic substrate was characterized by a dramatic increase in foliar levels of manganese and a decrease in Ca/Al ratios. Nitrogen and phosphorus levels increased, probably as result of concentration effects due to stunted growth. Discernment between Al- or Mn-toxicity was not possible. However for the soil tested, foliar Mn-levels appear to be useful for diagnosis of mineral stress induced by acidification because of the pronounced response. |
