Plinthite: Dothan Btv horizon (SC)
The upper meter of the subsoil horizon from a Dothan soil located in South Carolina, exhibiting an increasing amount of plinthite with depth. The reddish areas are very firm, dense and brittle, and are weakly cemented with iron. The area below the knife is root limiting in that zones that roots can enter are 10 or more centimeters apart (continuous phase plinthite).
This pedon would be classified as a "Plinthudult" if determined to have one or more horizons within 150 cm of the mineral soil surface in which plinthite either forms a continuous phase or constitutes one-half or more of the volume. Currently, there is not an established method for determining the quantity of plinthite nor an agree-to definition for "continuous phase" for plinthic materials. This layer would qualify as a "plinthic horizon" as proposed.
A water emersion disaggregation method (or slake test) has been developed to quantify plinthite, however, this method only identifies those plinthic materials that are cemented. Due to past application (primarily in Texas and California) the cementation requirement has not received unanimous acceptance in the soil science community. A proposed definition for "continuous phase" plinthite has been submitted. It is essentially the same as for other materials requiring a continuous phase in Soil Taxonomy.
For more information about Slake Tests, visit:
www.nrcs.usda.gov/sites/default/files/2023-01/SSIR51.pdf
Soil Survey Field and Laboratory Methods Manual; Soil Survey Investigations Report No. 51, Version 2; Issued 2014 (pp. 148-157)
3.7 Soil Stability, Dispersion, and Slaking
3.7.5 Slaking (Disaggregation) for Identification and Semiquantification of Cemented Materials
John Kelley and Michael A. Wilson, United States Department of Agriculture, Natural Resources Conservation
Service, Soil Survey Staff
According to USDA-Soil Taxonomy, Plinthudults are the more or less freely drained Udults that have a large amount of plinthite in the argillic or kandic horizon. They are mainly in intertropical regions and in some areas are extensive. Historically, they have not been identified in the United States and the great group has been provided for use in other parts of the world. As indicated by this image, this concept should be revisited.
For more information about describing soils, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/field...
For additional information about soil classification using Soil Taxonomy, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/keys-...
For more information about a plinthic horizon, visit;
www.researchgate.net/publication/242649722_Rationale_for_...
or:
www.sciencedirect.com/science/article/pii/S00167061220043...
or:
scisoc.confex.com/scisoc/2011am/webprogram/Paper67175.html
Plinthite: Dothan Btv horizon (SC)
The upper meter of the subsoil horizon from a Dothan soil located in South Carolina, exhibiting an increasing amount of plinthite with depth. The reddish areas are very firm, dense and brittle, and are weakly cemented with iron. The area below the knife is root limiting in that zones that roots can enter are 10 or more centimeters apart (continuous phase plinthite).
This pedon would be classified as a "Plinthudult" if determined to have one or more horizons within 150 cm of the mineral soil surface in which plinthite either forms a continuous phase or constitutes one-half or more of the volume. Currently, there is not an established method for determining the quantity of plinthite nor an agree-to definition for "continuous phase" for plinthic materials. This layer would qualify as a "plinthic horizon" as proposed.
A water emersion disaggregation method (or slake test) has been developed to quantify plinthite, however, this method only identifies those plinthic materials that are cemented. Due to past application (primarily in Texas and California) the cementation requirement has not received unanimous acceptance in the soil science community. A proposed definition for "continuous phase" plinthite has been submitted. It is essentially the same as for other materials requiring a continuous phase in Soil Taxonomy.
For more information about Slake Tests, visit:
www.nrcs.usda.gov/sites/default/files/2023-01/SSIR51.pdf
Soil Survey Field and Laboratory Methods Manual; Soil Survey Investigations Report No. 51, Version 2; Issued 2014 (pp. 148-157)
3.7 Soil Stability, Dispersion, and Slaking
3.7.5 Slaking (Disaggregation) for Identification and Semiquantification of Cemented Materials
John Kelley and Michael A. Wilson, United States Department of Agriculture, Natural Resources Conservation
Service, Soil Survey Staff
According to USDA-Soil Taxonomy, Plinthudults are the more or less freely drained Udults that have a large amount of plinthite in the argillic or kandic horizon. They are mainly in intertropical regions and in some areas are extensive. Historically, they have not been identified in the United States and the great group has been provided for use in other parts of the world. As indicated by this image, this concept should be revisited.
For more information about describing soils, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/field...
For additional information about soil classification using Soil Taxonomy, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/keys-...
For more information about a plinthic horizon, visit;
www.researchgate.net/publication/242649722_Rationale_for_...
or:
www.sciencedirect.com/science/article/pii/S00167061220043...
or:
scisoc.confex.com/scisoc/2011am/webprogram/Paper67175.html