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THE ASSESSMENT OF SOIL TEXTURE FROM SOIL STRENGTH MEASUREMENTS
Author(s) -
TOWNER G. D.
Publication year - 1974
Publication title -
journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 0022-4588
DOI - 10.1111/j.1365-2389.1974.tb01125.x
Subject(s) - penetrometer , soil water , soil texture , geotechnical engineering , soil science , shearing (physics) , water content , texture (cosmology) , environmental science , soil structure , soil gradation , mathematics , geology , computer science , artificial intelligence , image (mathematics)
Summary Soil texture is usually assessed by either the manipulation of the field soil in the hand or by a particle size analysis of the dispersed soil. These two methods are often regarded uncritically as alternatives, and this paper stresses the point of view that the hand manipulation method is the preferred one, because the particle size analysis method depends on the establishment of relevant correlations. However, the subjective nature of the first method is admitted, and the paper describes an attempt to devise an objective test based on the elements of the hand assessment. From the observation that one senses the reaction of the soil to compressive and shearing forces during an assessment by hand it is suggested that some measure of soil strength might be used as an index of texture. The strength of twenty‐three soils was measured over a range of water contents using the fall‐cone penetrometer. The curves representing the relationship between the strengths and the water contents were all of a similar shape and tended to form a regular array, with the lighter soils at the low water content end of the scale and the heavier soils at the higher end. They showed that the strength of a given soil was very sensitive to water content. It was concluded that the separation of the soils into the broad textural classes was made mainly from measurements of the strengths of the wetted soils, but that the more detailed descriptions, including for example, specification of the grade of the sand, required in addition an estimation of the sizes of the particles obtained by feeling them between the fingers. As a corollary, these finer divisions are not related to soil strength, and thus are dubious indications of heaviness or lightness.