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 por osity, soil temperature and soil respiration explained 66% of the spat ial variation in gas concentrations, when all soils and depths were in cluded. With the inclusion of complementary X variables, the model exp lained 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 w ater content originated in the early growing season and were condition ed by frozen soil layers, hampering the infiltration of water from sno wmelt. Soil moisture, rather than temperature, thus regulates the appa rent soil atmosphere variations in these forest soils of northern Swed en, where a temperate climate with cold and snowy winters and moist su mmer conditions prevails.