Distribution of Moved Clay in Four Loess-Derived Alfisols that Occur in Southern Illinois1
- R. B. Grossman and
- J. B. Fehrenbacher2
Measurements of moved clay by optical examination of thin sections are reported for four pedons of Alfisols developed in loess from southern Illinois.
Alford soils (Typic Hapludalfs) occur on the interfluve summits and Muren soils (Aquic Hapludalfs) on the locally associated sideslopes in areas of strong relief in Alexander County. The pedon of Muren is formed in an older loess than is the pedon of Alford. The pedon of Muren contains a twofold, higher maximum percentage of moved clay, and the maximum occurs at a shallower depth.
Wartrace soils (Typic Hapludalfs) and Hosmer soils (Typic Fragiudalfs) occur in local association in Johnson County. Wartrace soils occupy sites of slightly higher elevation on the ridgetops in a landscape of moderate to gentle relief. The moved clay in the Hosmer pedon reaches 9% (absolute) in the B2t; this is one-third of the total clay and twice the maximum percentage in the Wartrace pedon.
The study suggests three points that may be applicable to similar soils: (i) the fabric exclusive of the moved clay bodies can have appreciably lower clay than the total clay percentages would indicate; (ii) somewhat impeded internal drainage appears to favor local translocation of clay; (iii) amounts of moved clay are sufficient to account for the computed decrements in clay for the eluvial horizons.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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