RELATIONSHIPS BETWEEN SOIL PROPERTIES AND THE SOIL ATMOSPHERE IN SWEDISH FOREST SOILS

Concentrations of O-2 and CO2 in 11 mineral and peat forest soils were related to physical, chemical and biological site variables by means of PLS modelling. Soil depth, volumetric water content, air-filled porosity, soil temperature and soil respiration explained 66% of the spatial variation in gas concentrations, when all soils and depths were included. With the inclusion of complementary X variables, the model explained 76% of the Y variance. The X variables affecting gas transport in the soil explained more of both spatial and temporal gas variations than those affecting the biological activity. Much of the effect of water content originated in the early growing season and were conditioned by frozen soil layers, hampering the infiltration of water from snowmelt. Soil moisture, rather than temperature, thus regulates the apparent soil atmosphere variations in these forest soils of northern Sweden, where a temperate climate with cold and snowy winters and moist summer conditions prevails.