Horizon: Spodic horizon with ortstein?
The Spodic horizon is a subsurface soil horizon in which organic matter together with aluminum and often iron compounds have accumulated and is a diagnostic horizon in the USDA Soil Taxonomy. These horizons commonly occur in coarse-textured soils dominated by coniferous or other vegetation that contributes large amounts of soluble fulvic acids to the soil surface.
Ortstein is defined by Soil Survey Staff as all or part of the spodic horizon, when moist, is at least weakly cemented into a massive horizon that is present in more than half of each pedon.
In Spodosols, a partially cemented spodic horizon is used as family differentia. Spodosols that have a horizon with 50 to 90 percent ortstein have a have an ortstein rupture-resistance family class.
Continuous Ortstein is defined as 90 percent or more cemented and has lateral continuity (Durorthods). Because of this continuity, roots can penetrate only along vertical fractures with a horizontal spacing of 10 cm or more.
Note in this pedon, roots have not penetrated into the dark colored spodic material indicating possible cementation. Fist-size pieces of the horizon were checked for cementation by the water immersion disaggregation test. Although some of the horizon was weakly cemented, less than half of the materials tested exhibited cementation. Therefore, the spodic horizon did not meet the definition for the ortstein family.
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-...
Horizon: Spodic horizon with ortstein?
The Spodic horizon is a subsurface soil horizon in which organic matter together with aluminum and often iron compounds have accumulated and is a diagnostic horizon in the USDA Soil Taxonomy. These horizons commonly occur in coarse-textured soils dominated by coniferous or other vegetation that contributes large amounts of soluble fulvic acids to the soil surface.
Ortstein is defined by Soil Survey Staff as all or part of the spodic horizon, when moist, is at least weakly cemented into a massive horizon that is present in more than half of each pedon.
In Spodosols, a partially cemented spodic horizon is used as family differentia. Spodosols that have a horizon with 50 to 90 percent ortstein have a have an ortstein rupture-resistance family class.
Continuous Ortstein is defined as 90 percent or more cemented and has lateral continuity (Durorthods). Because of this continuity, roots can penetrate only along vertical fractures with a horizontal spacing of 10 cm or more.
Note in this pedon, roots have not penetrated into the dark colored spodic material indicating possible cementation. Fist-size pieces of the horizon were checked for cementation by the water immersion disaggregation test. Although some of the horizon was weakly cemented, less than half of the materials tested exhibited cementation. Therefore, the spodic horizon did not meet the definition for the ortstein family.
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-...