Refining the Definition of Field Capacity in the Literature

Abstract

The normalized water content calculated with the simple algebraic equation θ\df\dc = (\Iq\N\df\dc/K\ds)¹/\un, where \iq\df\dc = 0.5 mm/day and \iK\i\ds = hydraulic conductivity, can be used to estimate field capacity. The water content calculated with this relationship is close to the water content at 1/3 bar matric potential for all soils. It is suggested that the concept of “field capacity” be refined by relating it to the mobility of soil moisture (drainage flux). Field capacity should not be characterized solely by a particular drainage time, because the time to reach field capacity depends on soil properties, but also on the initial water content and water depth in the soil.