
TY  - JOUR
A1  - Buchan, GD 
A1  - Grewal, KS 
A1  - Claydon, JJ 
A1  - Mcpherson, RJ 
T1  - A Ccomparison of sedigraph and pipette methods for soil particle-size analysis
JF  - Soil Research
JO  - Soil Res.
Y1  - 1993
VL  - 31
IS  - 4
SP  - 407
EP  - 417
KW  - Particle-Size Analysis;Sedigraph;Pipette Method;Soil Iron;
UR  - https://doi.org/10.1071/SR9930407 
N2  - The X-ray attenuation (Sedigraph) method for particle-size analysis is known to consistently estimate a finer size distribution than the pipette method. The objectives of this study were to compare the two methods, and to explore the reasons for their divergence. The methods are compared using two data sets from measurements made independently in two New Zealand laboratories, on two different sets of New Zealand soils, covering a range of textures and parent materials. The Sedigraph method gave systematically greater mass percentages at the four measurement diameters (20, 10, 5 and 2 µm). For one data set, the difference between clay (<2 µm) percentages from the two methods is shown to be positively correlated (R2 = 0.625) with total iron content of the sample, for all but one of the soils. This supports a novel hypothesis that the typically greater concentration of Fe (a strong X-ray absorber) in smaller size fractions is the major factor causing the difference. Regression equations are presented for converting the Sedigraph data to their pipette equivalents. 
ER  -

