Abstract

This study concerns soil air as a part of the three phase system, solid material, water and air which forms the soil. An idea of soil air, volume, composition, ecological significance and exchange mechanisms, is formed from the literature. An apparatus for experiments with gas diffusion through naturally layered moist soils is described. The possible replenishment of soil air by diffusion and mass flow is studied. A study on gas diffusion and mass flow on a number of dry and wet laboratory prepared soils is carried out, followed by a study of a number of well described naturally layered soils. From the information acquired so far, the possible significance of the experimental results on the composition of soil air and its ecological effects is discussed. The final conclusions are in agreement to those of Lundegårdh (1927), soil aeration status must be regarded on exchange possibilities on the one side and production and consumption of its components on the other, a highly dynamic system.