Biochemical activities of soil microflora in SO2 polluted forest stands

The microbial colonization and soil biochemical activities were followed on the Ore Mountain tops in NW Bohemia for 1–2 years in a residual young spruce stand, grass-covered withered spruce stand and grass-covered mountain-ash and birch stands. In grass-covered stands the soil pH value spontaneously increased. Concentrations of heterotrophic bacteria were higher by one or two orders of magnitude than those in a spruce stand without ground vegetation; soil respiration, ammonification and nitrification increased. Bacterial communities of the fermentation horizon were better equipped with degradation and mineralization activities than communities of the spruce stand. These results are in contradiction to the assumption that SO₂ mmissions induce intoxication of the soil making microbial life impossible.