Characterizing soil aeration with a platinum microelectrode. I. Response in relation to field moisture conditions and electrode diameter

Abstract

Measurements with a platinum microelectrode under field conditions in a range of irrigated soils have been analysed in terms of applicability of the method for the field measurement of soil aeration. In well-drained soils the moisture content fell below the range in which the electrode operates satisfactorily within 2 days of heavy watering, but in poorly drained soils the electrode remained operative for up to 6 days. Field measurements were made with an electrode of 1.22 mm diameter, so diffusion theory was applied to convert the values to those for a 0.50 mm diameter electrode, a size more frequently used. Measurements were then made under controlled conditions in saturated and unsaturated media to confirm the theoretical determinations.