The Assessment of Soil Texture From Soil Strength Measurements

Abstract

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.

A Comparison of Field Estimates and Laboratory Analyses of the Silt and Clay Contents of Some West Midland Soils

“…T o avoid the confusion inherent in the use o 7 this word, the Soil Survey uses the term 'particle-size class' in preference to 'soil texture' to express the groupings based on the proportions of sand, silt, and clay size grades. As Soane et al (1972) point out, the description of soils on the basis of particle-size distribution alone is unlikely to give a clear indication of their hysical pro erties or behaviour in the field, and the newly revised I 60), outlines the methods of assessment of those readily observable organic matter content, particle-size distribution of the mineral fraction, the grade, size, shape and development of the peds or soil fragments and the strength, stickiness, plasticity, porosity, acking density, and stonidescription of all these properties leads to a far better appraisal of soil behaviour in the field than a simple all-embracing judgement of texture, undefined in terms of particle-size composition and embodying other roperties including aspects of consistence and organic matter content Towner, 1974 Worcester, and Salop. The profiles belong to five major groups: Pelosols, Brown soils, Podzohc soils, Surface-water gley soils, and Ground-water gley soils (Avery, I 73), and represent seventeen subgroups and thirty-eight soil series.…”

Assessing Indigenous Soil Ureolytic Bacteria as Potential Agents for Soil Stabilization

“…A total of ten soil samples were collected from the topsoil layer of Ladang 15, Faculty of Agriculture (2°36'05''N 102°42'11''E), Universiti Putra Malaysia in Selangor, Malaysia based on methods adapted from Kang et al (2015). The soil samples type and texture were determined as described by Towner (1974) and Ritchey et al (2015). Meanwhile, pH of soil samples was measured using a standard pH meter as described by Kalra (1995).…”

Adequacy of low-cost technique for soil bacterial alginate/zein encapsulation at laboratory scale

“…species (unpublished data). According to their texture, the soil in this area is classified as clay loam [25], whose major trait when assuring texture soil by hand is that it is easily molded and rolled into threads [26]. The S1_08 strain was isolated and replicated on LB, Miller broth medium for 24 hours at 25ºC under agitation at 125 rpm in an orbital shaker incubator.…”