THE DEPENDENCE OF FIELD CAPACITY UPON THE DEPTH OF WETTING OF FIELD SOILS

Abstract

Natural and artificial irrigation of initially dry mountain soil plota showed the moisture content of the surface layer shortly after wetting increased with increasing wet depth. The max. moisture at a stated depth, corresponding to field capacity, was found only after soil had been wetted 6 to 30 in. below that depth. Tentative explanations are offered based upon water available for drainage, moisture potential gradients, and permeability. Results suggest that shallow irrigations may not provide valid measures of field capacity.