A DEVICE FOR DETERMINING THE SORPTIVITY OF SOIL AGGREGATES

A device that infiltrated water over a small circular surface area hav ing a radius ranging between 1.45 mm and 2.5 mm was used to measure th e sorptivity of initially air-dry aggregates of size greater than 20 m m. The small infiltration area caused the water uptake to be dominated by capillarity that allowed the use of a simple formula to obtain the sorptivity from the steady-state flow rate that occurred very early a fter the start of inhibition. The results of measurements of sorptivit y made on a fine sand agreed with those obtained from measurements on one-dimensional water infiltration into columns of the sand. Sorptivit y measurements on stabilized aggregates of a clay soil and on air-drie d field aggregates of a clay soil were easily made. The simplicity and rapidity of the method allowed measurements to be conveniently replic ated.