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Aggregation indices to characterize structural breakdown of dry soil samples by air slaking
Author(s) -
Roth Christian H.
Publication year - 1996
Publication title -
zeitschrift für pflanzenernährung und bodenkunde
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.644
H-Index - 87
eISSN - 1522-2624
pISSN - 0044-3263
DOI - 10.1002/jpln.1996.3581590504
Subject(s) - soil water , loess , soil science , soil structure , water content , soil test , environmental science , hydraulic conductivity , geotechnical engineering , geology , geomorphology
The objectives of this study were to develop a simple test to assess air slaking effects on structural breakdown of dry soils and with the help of the test, to verify whether observations made by Gath (1995) on artificial soil samples are also valid for undisturbed soil samples. The proposed slaking test and the derived aggregation indices allow for an indirect assessment of the effect of air slaking. It is possible to use the test as a means of grouping soil structure with respect to slaking susceptibility. Thus, soil samples with clay contents < 10% and granular or weakly coherent structure are practically completely dispersed upon immersion. Soils with > 30% clay are well aggregated in angular blocks and prisms, and slaking will stop at a microaggregate level. Loess soils, which usually have a range of 10 to 30% clay content and coherent to subangular blocky structure show an intermediate behaviour. Finally, the results obtained here using undisturbed soil samples are in line with those obtained by Gäth (1995), indicating that at a given water content rate of water uptake as influenced by hydraulic conductivity, sample size and bulk density is a major factor controlling effects of air slaking. However, when comparing samples of different origin, increase in clay content is the principal factor that reduces slaking effects.