The Solodic Subgroup: A Proposed Amendment to Soil Taxonomy1
- B. F. McQuaid,
- B. A. Schumacher and
- B. J. Miller2
Results of characterization and field studies in Louisiana have shown that some soils have ≧ 15% exchangeable Na (ESP) at depths greater than those defined for the natric horizons in Soil Taxonomy (Soil Survey Staff, 1975). In these soils, horizons meet all criteria for the natric horizon with the exception of depth which ranges from 40 to more than 125 cm below the top of the argillic horizon. In many areas, reduction in crop yields of deep rooting annual or perennial plants growing in these soils is attributed to large quantities of exchangeable Na. It is proposed that a Solodic subgroup be included as an amendment to Soil Taxonomy to accommodate soils having an ESP of ≧15 (SAR ≧ 13) in some subhorizon within 1.25 m of the surface or an ESP ≧ 6 (SAR ≧ 5) and <15 (SAR < 13) within the upper 40 cm of the argillic horizon. The proposed subgroup does not affect the classification of soils with natric horizons.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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