Courtesy A. J. Turgeon
Soil aeration is the process by which soil air is replaced by atmospheric air. Soil air differs from atmospheric air in that it has higher concentrations of carbon dioxide and water vapor, but less oxygen. The differences are due to the consumption of oxygen and production of carbon dioxide by soil organisms. The magnitude of these differences depends on the rate of gaseous exchange between the atmosphere and the soil. This exchange is often associated with the movement of water into and out of the soil.