Biological activity and amount of FDA mycelium in mor humus of Scots pine stands (Pinus sylvestris L.) in relation to soil properties and degree of pollution

Abstract

The biological activity and the amount of living fungal mycelium in the mor humus of pine forests around an industrialized city were studied. The activities were lower in the more polluted zone than in a cleaner one but varied between sites within the zones. The relationship of these activities to the microbial environment was determined in both the total data and in the various zones separately. Soil respiration rate was positively related to ammonium nitrogen concentration of the humus in the less polluted zone but negatively in the more polluted zone, while it related negatively to total nitrogen concentration of the humus in the entire data set. DHA was partly accounted for by the variation in acidity parameters, and best by pH(CaCl2), with a positive relation. The length of FDA active fungal mycelium showed no significant variation between the zones or sites, and was thus poorly explained by the environmental variables. The weather conditions prevailing at two seasons did not explain any variation of the activities or the length of FDA mycelium, though the biological variables were in general positively related to the moisture of the humus.