Hb. So et al., AN EXAMINATION OF THE END-OVER-END SHAKING TECHNIQUE FOR MEASURING SOIL DISPERSION, Australian Journal of Soil Research, 35(1), 1997, pp. 31-39
The end-over-end shaking technique has been widely used to provide a m
easure of soil dispersibility. However, results are dependent on the s
pecific methodology employed. This paper investigates the effect of va
rious physical parameters on the dispersion produced using an end-over
-end shaking technique. Significant (P < 0.05) increases in the percen
tages of clay (D-2) and silt+clay (D-20) particles dispersed as a prop
ortion of the total soil weight were observed with increasing period o
f shaking, suspension concentration, container size, and air-gap above
the suspension. However, differences due to suspension temperature an
d soil texture were either relatively minor or insignificant (P > 0.05
). To enable better comparison of results from different workers, the
following methodology for end-over-end shaking studies is proposed as
a standard. The soil sample should be air-dried and crushed to pass th
rough a 2-mm sieve. The air-dried equivalent of 50 g oven-dried soil s
hould then be immersed in 1 L double-deionised water at 20 degrees C w
ithin a 1.425-L cylinder (70 mm internal diameter) and shaken end-over
-end at 20 rpm for 30 min before measuring the amount of dispersed <2
and <20 mu m material produced. The amount of dispersed material shoul
d be expressed as a proportion of the total soil material.