Particle-Size Analysis by a Modified Pipette Procedure

Abstract

The most widely accepted method for particle-size determination is the pipette extraction method. The method is precise when properly performed, but consumes both time and space. A modified, more rapid version of the method is presented and compared with a version of the standard procedure. The modified procedure differs in that a single vessel called a Fleaker is used to disperse and pipette the sample prior to the removal of sands by wet sieving, making the transfer to a soil-sedimentation cylinder unnecessary. Fleakers cost less than cylinders, allow for quicker sample preparation, and permit more samples to be analyzed at one time in less space. Statistical analysis of variation (ANOVA) revealed nonsignificant effects for the procedure × sample interaction. This indicated that the performance of the standard and modified procedures were not affected by the soil textures and mineralogies tested. Regression analysis revealed a one-to-one relationship for percent clay determined by the standard and modified procedures. Reduced time and space requirements will result in long-term cost reductions for particle-size analysis, particularly in production laboratories and in studies that require a large soils data base.