Clay films (the brown waxy areas) in a Btvx horizon
Translocated clay along ped faces is called clay films or argillans. They appear as a waxy coating. If stained with iron, they are identified as ferriargillians or with organic matter, organoargillans.
Soil horizons with sufficient clay illuviation are identified as argillic horizons. This is an example of a Btvx horizon from the lower subsoil of a coastal plain soil.
The quantity and extend of the clay films (brown colored area) indicate Illuvial accumulation of silicate clay. ("t" suffix).
The red zones are dense and brittle, are weakly cemented, and are evident of plinthite ("v" suffix).
The horizon exhibits fragic soil properties--root limiting, dense and brittle ("x" suffix). Note: Roots are along the structure faces not ped interiors. It is important to note not only the presence/absence of roots, but the spacing in which roots can enter. (A fragipan has separations between structural units that allow roots to enter have an average spacing of 10 cm or more on the horizontal dimensions.)
This pedon is classified as a Plinthic Kandiudult--the Dothan series. soilseries.sc.egov.usda.gov/OSD_Docs/D/DOTHAN.html
Fragic soil properties at the subgroup level are not currently acknowledged in Kandiudults.
For more information about describing and sampling soils, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/field...
or Chapter 3 of the Soil Survey manual:
www.nrcs.usda.gov/sites/default/files/2022-09/The-Soil-Su...
For additional information on "How to Use the Field Book for Describing and Sampling Soils" (video reference), visit:
www.youtube.com/watch?v=e_hQaXV7MpM
For additional information about soil classification using USDA-NRCS Soil Taxonomy, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/keys-...
or;
www.nrcs.usda.gov/resources/guides-and-instructions/soil-...
Clay films (the brown waxy areas) in a Btvx horizon
Translocated clay along ped faces is called clay films or argillans. They appear as a waxy coating. If stained with iron, they are identified as ferriargillians or with organic matter, organoargillans.
Soil horizons with sufficient clay illuviation are identified as argillic horizons. This is an example of a Btvx horizon from the lower subsoil of a coastal plain soil.
The quantity and extend of the clay films (brown colored area) indicate Illuvial accumulation of silicate clay. ("t" suffix).
The red zones are dense and brittle, are weakly cemented, and are evident of plinthite ("v" suffix).
The horizon exhibits fragic soil properties--root limiting, dense and brittle ("x" suffix). Note: Roots are along the structure faces not ped interiors. It is important to note not only the presence/absence of roots, but the spacing in which roots can enter. (A fragipan has separations between structural units that allow roots to enter have an average spacing of 10 cm or more on the horizontal dimensions.)
This pedon is classified as a Plinthic Kandiudult--the Dothan series. soilseries.sc.egov.usda.gov/OSD_Docs/D/DOTHAN.html
Fragic soil properties at the subgroup level are not currently acknowledged in Kandiudults.
For more information about describing and sampling soils, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/field...
or Chapter 3 of the Soil Survey manual:
www.nrcs.usda.gov/sites/default/files/2022-09/The-Soil-Su...
For additional information on "How to Use the Field Book for Describing and Sampling Soils" (video reference), visit:
www.youtube.com/watch?v=e_hQaXV7MpM
For additional information about soil classification using USDA-NRCS Soil Taxonomy, visit:
www.nrcs.usda.gov/resources/guides-and-instructions/keys-...
or;
www.nrcs.usda.gov/resources/guides-and-instructions/soil-...