Responses of soil microorganisms and water content in forest floor horizons to environmental factors

Abstract

The study focused on the temporal dynamics of soil water content (SWC) and soil microbial activity characterized by basal respiration and catalase activity in the litter (OL), fragmented (OF), and humus (OH) subhorizons of the forest floor and the mineral A-horizon, in relation to air temperature and rainfall. The study was conducted at three plots (old-growth Norway spruce (Picea abies Karst.) forest, even-aged mature commercial spruce stand, grassland dominated by Calamagrostis sp.) located in the Biosphere Reserve Polana (Slovakia, 19°28′E, 48°38′N) during four years. SWC as well as microbial activity differed among horizons as well as among plots. Generally, organic horizons in the old-growth forest exhibited higher microbial activity than in the managed forest, but no significant differences were observed for the A-horizon. On the other hand, the A-horizon showed higher catalase activity in the grassland than in both forest stands. The responses of SWC and microbial activity to air temperature and rainfall differed among horizons. SWC responded most sensitively to short-term temperature fluctuations in the OL horizon. In the underlying horizons, cumulative positive effects of high temperature (lasting 5–15 days) were reflected in the basal respiration. SWC responded rapidly to precipitations, but the effect lasted generally not more than 2 days. In contrast, catalase activity was negatively correlated with the precipitation amount; however, with increasing depth this relationship became less distinct.