RESPONSES OF FOREST SOUL TO MODERATE ANTHROPOGENIC AIR-POLLUTION - A LARGE-SCALE FIELD SURVEY

There is a need to introduce soil microbiological methods into long te rm ecological monitoring programs. For this purpose we studied the imp act of moderate anthropogenic air pollution in polluted and less pollu ted area districts, forest site types Calluna (CT), Vaccinium (VT) and Myrtillus (MT) and the amount of organic matter, measured as carbon c ontent on the soil respiration activity and the ATP content. The main sources of local air pollutants (SO2 and NO,) in the polluted area dis trict were from the capital region and an oil refinery. Humus (F/H-lay er) and the underlying 0 to 5 cm mineral soil samples were collected f rom 193 study plots located in the 5300 km(2) study area. We found tha t the soil respiration rate in humus layer samples was lower in the po lluted area district compared to the less polluted one (16.0 and 19.5 mu L CO2 h(-1)g(-1) dw, respectively), but the difference occurred onl y in the dry, coarse-textured CT forest site type. The mineral soil re spiration rate and the mineral soil and humus layer ATP content were n ot affected by the air pollution. Most of the variations of the biolog ical variables were explained primarily by the soil carbon content, se condly by the forest site type and thirdly by the area division.