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Soil Science Society of America Journal Abstract -

Cole Determination by Thermomechanical Analysis1


This article in SSSAJ

  1. Vol. 43 No. 2, p. 427-428
    Received: Feb 8, 1978
    Accepted: Oct 9, 1978

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  1. B. F. Hajek2



The coefficient of linear extensibility (COLE) is used as a criterion to differentiate vertic from typic subgroups. The ratio, (Lm − Ld) ÷ Ld, in which Lm is the length at 1/3 — bar moisture tension and Ld is the air-dry length of a soil clod, is used to calculate this coefficient. Length changes can be obtained from measurements of moist and dry soil cores. COLE can also be calculated from moist and dry bulk density values. The objective of the study was to evaluate the use of the thermomechanical analyzer (TMA) for the measurement of soil ped length change as the ped is dried. The TMA unit is available as a plug-in module for thermal analysis systems. Field moist (approximately at field capacity) and 1/3 — bar soil peds were selected from six soils and analyzed by this method. TMA-COLE values from 0.126 to 0.010 were calculated from length change values. About 30 min was required for each measurement of field moist peds. This is a rapid procedure for shrinkage estimation since it requires essentially no preliminary preparation.

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