Column-centrifugation method for determining water retention curves of soils and disperse sediments

A new instrumental method was proposed for the rapid estimation of the water-retention capacity of soils and sediments. The method is based on the use of a centrifugal field to remove water from distributed soil columns. In distinction from the classical method of high columns, the use of a centrifugal force field stronger than the gravity field allowed reducing the height of the soil samples from several meters to 10-20 cm (the typical size of centrifuge bags). In distinction from equilibrium centrifugation, the proposed method obtained an almost continuous water retention curve during the rotation of the soil column only at one-two centrifuge speeds. The procedure was simple in use, had high accuracy, and obtained reliable relationships between the capillary-sorption water potential and the soil water content in a wide range from the total water capacity to the wilting point.