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A Comparison of Clay Contents Determined by Hydrometer and Pipette Methods Using Reduced Major Axis Analysis
Author(s) -
Liu T. K.,
Odell R. T.,
Etter W. C.,
Thornburn T. H.
Publication year - 1966
Publication title -
soil science society of america journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.836
H-Index - 168
eISSN - 1435-0661
pISSN - 0361-5995
DOI - 10.2136/sssaj1966.03615995003000060008x
Subject(s) - pipette , clay soil , mineralogy , soil test , soil science , mathematics , statistical analysis , chemistry , geology , statistics , soil water
Test results on the amount of <0.002 mm clay determined by hydrometer and pipette methods have been obtained from 155 duplicate soil samples, of which 48 are from Illinois and the remaining 107 are from soil survey reports published by the Soil Conservation Service in cooperation with 10 other states. Correlation analysis of the data yielded a highly significant coefficient of 0.965. The best‐fit line between the clay contents determined by these two procedures was obtained by the reduced major axis method of statistical analysis. In this statistical method, neither one of the two variables is considered as the dependent variable and the reduced major axis is determined by mininizing the sum of the areas of triangles formed by lines drawn from each point to the best‐fit line and paralle with the X and Y axes. The relationship between the clay contents is expressed by the equation Y = 0.63 + 1.008 X, in which X and Y represent the pipette and hydrometer clay content, respectively. Clay contents determined by these two methods are quite similar, although there is a tendency for hydrometer analyses to be slightly higher. Relationships between data from Illinois and other states are very similar. The slightly poorer correlation between clay contents of A horizons as compared to other horizons may have been caused by organic matter which was not removed in hydrometer analysis.