Hydrolytic enzyme activities, carbon dioxide production and the growth of litter degrading fungi in different soil layers in a coniferous forest in Northern Finland

Abstract

To establish the importance of the layered soil structure to microbial activities, the growth of litter degrading fungi, and the chemical status of forest soil in a cold climate, we studied carbon dioxide production and five hydrolytic enzyme activities in the humus, eluvial and illuvial layers at three sites in an acidic Pinus sylvestris forest soil at Inari, northern Finland. The enzyme activities were low (<30%) in extracts of soil compared to those in the corresponding soil layers, indicating that the enzymes were largely particle-bound. Carbon dioxide production, and β-glucosidase, β-xylosidase, α-glucosidase and butyrate esterase activities were highest in the humus layer in the soil column. The litter degrading fungi Agaricus bisporus, Agrocybe praecox, Gymnopilus luteofolius, Gymnopilus sapineus, Mycena galericulata and Stropharia rugosoannulata produced extracellular hydrolytic enzymes in the humus and eluvial soil layer plates, but not in the illuvial soil layer plates. Sulphatase activity was higher in the layers below the humus layer in the soil column. Carbon dioxide production, and β-glucosidase, β-xylosidase, α-glucosidase and butyrate esterase activities were significant below humus layer in the eluvial and illuvial layers in the soil column, indicating the importance of these deeper layers in microbial metabolic functioning and depolymerization of biopolymers in the soil column in cold climate in Northern Finland.