The maximum water-retaining capacity of colloidal soils; the interpretation of this and of certain other soil moisture constants

Abstract

The maximum water-retaining capacity of a soil may be defined as the quantity of water, measured as a percentage of the mass of oven-dry material, that the soil can retain after it has been thoroughly wetted and then allowed to drain freely. It is generally estimated in the laboratory by Hilgard's method (1893). The air-dried sifted soil is packed by jarring into a small perforated cylindrical brass box which is then placed in a vessel containing water, so that the bottom layer of the soil is in contact with the liquid surface. After standing an hour, the cylinder is removed, surplus water wiped away, and the whole weighed. The cylinder and contents are then dried to constant mass in an air-oven at 110° C. The weighings are corrected for the mass of the cylinder and that of the filter paper employed to cover the sieve. From the results, the maximum water-retaining capacity may directly be calculated.