A MODIFIED PROCEDURE FOR THE MORE RAPID DETERMINATION OF THE CLAY CONTENT (<2HM) OF SOILS

A modified procedure for dispersing soils for particle size analysis, using centrifuge tubes, has been tested and described. It is suited for most soils and although designed primarily for the more rapid determination of clay content, offers a faster alternative procedure for silt and sand content as well. Some factors determining rate of analysis and clay yields were evaluated and discussed. When % clay alone is required, the modified procedure is about three times faster than the existing routine methods for large numbers of samples requiring chemical pretreatments. The modified procedure gave the same clay yields as the mixer mill for normal soils but is unsuited to highly sub- plastic soils. /Author/TRRL/