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This article in SSSAJ

  1. Vol. 46 No. 6, p. 1274-1279
    Received: Nov 17, 1981
    Accepted: Aug 30, 1982

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Dry Soil-Aggregate Stability: Energy-Based Index1

  1. E. L. Skidmore and
  2. D. H. Powers2



Most methods used to estimate aggregate stability apply an unmeasured force, or a measured force without knowledge of transfer, to a single or a group of aggregates. A technique is needed to estimate aggregate stability based on quantitative transfer of energy. This paper presents an energy-based procedure for evaluating dry-aggregate stability. Soil aggregates were crushed by diametrically loading them between parallel plates. The energy of crushing was determined by integrating the area under the force against distance curve. The aggregate-surface area after comminution was calculated from aggregate-size distribution and aggregate density; the aggregates were assumed to be spherical. The results are expressed as energy per unit of surface area, joules per meter squared (J/m2). Example values obtained from field-sampled aggregates for several soil series ranged from 3.7 ± 0.7 for Hotlake silt loam (coarse-silty, mixed, mesic Aquic Haploxerolls) to 43.9 ± 7.5 for Bearden silt loam (fine-silty, frigid Aeric Calciaquolls). The wide range of aggregate stabilities among different soils made it possible to distinguish among them even though variability among aggregates of the same soil was relatively large. The results were relatively insensitive to initial aggregate size but sensitive to crushing end point.

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