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2016 NCSS Regional Standards and Taxonomy Committee Proposals

The following proposals and issues are presented for the consideration and deliberation of the 2016 NCSS Regional Committees for Standards and Taxonomy. Items under Part A are the resolutions to the proposals forwarded from Regional and National NCSS conferences since 2014. A short statement of the issue, the fix, and the cost is provided for reference. Clicking on the hyperlink will display the text as it will be integrated into the Keys to Soil Taxonomy if concurred by the regional committees. 

Items under Part B are proposals received this year for first consideration at the Regional Conferences. Additional proposals will be added to the list and available for other regions to consider if sent to Dr. Curtis Monger, National Leader for Soil Survey Standards, USDA-NRCS-NSSC. The new proposals can be accessed via the hyperlink. 

Items listed under Part C are presented for your review and feedback. These items are “works in progress” which would benefit from your experience and feedback. Formal proposals for adoption or amendment have not yet been developed for your complete review.
 

  1. Resolutions to Proposals on Soil Taxonomy from the 2015 Conference
     
    1. Aquic Hapludults – Phil King et al. (PDF; 12 KB)

      What is the issue?

      The variable depth (floating datum) effect upon the Aquic subgroup classification when top of the argillic determines starting point of the criteria rather than soil surface.

      What is the fix?

      Modify the criteria for depth to saturation/water table being determined from soil surface.

      What is the cost?

      Minimal, change in Aquic subgroup criteria used in the Hapludults (2 subgroups impacted). A number of series will be affected and need reclassification.
       

    2. Calcareous Fens – Doug Wysocki et al. (PDF; 12 KB)

      What is the issue?

      Organic soils in fens (discharge, mineral-rich wetland) can be highly calcareous due to precipitation of carbonates from upwelling ground water. The hydrology and chemistry in these soils is significantly different than other Histosols.

      What is the fix?

      Create a family reaction class of “kalkic” for Histosols to cover calcareous organic soils, and clarify definition of Wassents to prevent fens from being treated as subaqueous soils.

      What is the cost?

      Minimal cost, significant impact in separating calcareous organic soils from highly acidic organic soils.
       

    3. Epi vs. Endo and the Densic Contact – Mark Stolt et al. (PDF; 151 KB)

      What is the issue?

      Water tables perched on top of glacial densic contacts key out as endosaturation instead of episaturation due to ambiguity in whether materials below densic contact are considered as unsaturated layers in Soil Taxonomy.

      What is the fix?

      Clarify statement regarding how materials below contacts (densic, lithic, paralithic, or petroferric contact) are considered in Soil Taxonomy and clarify the definitions of endosaturation (all layers saturated) and episaturation (having unsaturated layers within 200 cm, but below a perched water table).

      What is the cost?

      Important correction maintaining perched water tables atop till (episaturation). Correction is easy. Impacts a number of soil series in the northeast which were reclassified as having conditions of endosaturation based upon the wording in the Keys.
       

    4. Subaqueous Soil Revisions – Jim Turenne, Mark Stolt, et al. (PDF; 118 KB)

      What is the issue?

      As examination, mapping, and analyses of subaqueous soils continues, changes in terminology or criteria as well as addition of additional classes are warranted.

      What is the fix?

      Redefinition of terms applied in subaqueous soil mapping and classification where developed. Additional taxonomic classes added.

      What is the cost?

      Minimal cost and minimal impact outside of subaqueous soils realm.

       

  2. New Proposals for Changes in Soil Taxonomy for 2016 Regional Meetings

    1. Proposed Densic Great Groups of Udepts and Aquepts – Mark H. Stolt, Deborah Surabian, Donald Parizek, James Turenne, and Jacob Isleib (PDF; 189 KB)

      What is the issue?

      Densic contacts are not recognized in Soil Taxonomy in the classification hierarchy.

      What is the fix?

      For the Udepts and Aquepts Suborders, develop appropriate Great Groups and corresponding Subgroups for soils with densic contacts within 100 cm of the soil surface (Densiaquepts, Densiudepts).

      What is the cost?

      Impact may be significant in northeastern glaciated regions.
       

    2. Proposed Changes for Spodosols and Spodic Horizon Designations – Mark H. Stolt and Martin C. Rabenhorst (PDF; 439 KB)

      What is the issue?

      Many Aquods lack sufficient iron to produce redoximorphic features; the maximum Fe content in Alaquods and Alorthods is currently set too low for many taxa to meet; there is ambiguity in distinguishing Bh from Bhs horizons in the field with current definition.

      What is the fix?

      Require Aquods to only meet Aquic Conditions (remove redoximorphic feature requirement); redefine the requirement for Alaquods and Alorthods to require <0.1% ammonium oxalate extractable (AOE) Fe, or 3 times more AOE Al than Fe; refine distinction and definition of Bh and Bhs horizons

      What is the cost?

      Some Spodosols will need evaluation and reclassification.
       

    3. Proposed Changes in Limnic Horizons and Materials – Ed Tallyn, Thor Thorson, et al. (PDF; 15.9 MB)
      Note: To view the supporting descriptions and documentation attachments, be sure to click on the attachments tab (paperclip icon) on left sidebar on the Adobe Acrobat Reader frame.

      What is the issue?

      Limnic horizons and materials are treated as organic soils as currently placed in Soil Taxonomy. These materials occur in significant quantities outside of the soils meeting the requirement for Histosols, yet very little treatment is given them. Redefinition and clarification of limnic materials is needed as well as the addition of taxa and classes to adequately convey important characteristics in Soil Taxonomy.

      What is the fix?

      To more completely describe, classify, and interpret soil material or soil horizons containing significant amounts of limnic material which do not classify as Histosols. Five proposals have been made regarding the description and identification of limnic materials: 1) consideration outside of Histosols, 2) limnic materials as texture modifiers, 3) creation of new Limnic subgroups, 4) use of in-lieu-of-texture modifiers for limnic materials, and 5) addition of a diatomaceous mineralogy (Opaline).

      What is the cost?

      Numerous revisions throughout Taxonomy. Would take some time to implement, but impact upon other taxa would be minimum.

       

  3. Issues for Discussion and Further Development

    1. Surface Mantle Clarifications – Craig Ditzler, Ken Scheffe (PDF; 23 KB)

      What is the issue?

      Surface mantle and buried soil concepts not adequately defined.

      What is the fix?

      Added description of surface mantle and clarified concepts and distinctions between surface mantle and buried soil.

      What is the cost?

      Completed.
       

    2.  Bedrock, Fragments, and Densic Materials Decision Tree – Wayne Gabriel, Ed Tallyn, et al. (PDF; 128 KB)

      What is the issue?

      Need for a unified decision tree regarding bedrock, densic material, and fragments in soils.

      What is the fix?

      Key developed by regional soils staff has been developed and vetted. They wish this to be adopted as a standard tool used in the identification of these materials.

      What is the cost?

      Requesting more review to be fully vetted for accuracy and application. No negative impact.
       

    3. Isotic Mineralogy in Sandy Soils – Joe Chiaretti et al., Ken Scheffe, Mike England (PDF; 41 KB)

      What is the issue?

      Some very sandy soils give a false positive indicating presence of amorphous or short-range ordered minerals present with current Isotic Mineralogy criteria (NaF pH and 1500Kpa water retention to clay ratio) when this mineralogy is not present.

      What is the fix?

      Redefinition of the isotic mineralogy criteria excluding very sandy soils and raising the NaF pH requirement to 9.4.

      What is the cost?

      Impact and time requirements could be great. Currently over 1,000 series with isotic mineralogy. Soils forming in volcanic materials and many Spodosols would need to be evaluated and many reclassified. Currently, approximately 120 series that have sandy or sandy-skeletal PSC with isotic mineralogy.
       

    4. Initiation of Yermic Diagnostic Feature Investigations Project – Ken Scheffe (PDF; 96 KB)

      What is the issue?

      The Vesicular Master Horizon was adopted in 2014, but not fully evaluated through for inclusion in Soil Taxonomy nor soil interpretations. Additional field studies and investigations are needed to fully integrate the vesicular horizon and potentially add the yermic (vesicular) diagnostic feature into Taxonomy, as well as to identify and interpret soils with yermic features relative to use and management. The yermic pedogenic feature is identified in other soil classification systems.

      What is the fix?

      Fieldwork and sampling for characterization is needed to quantify the yermic horizon to establish diagnostic features and classes. Suggesting a 2-year study with support of soil survey offices and NCSS partners, primarily in the arid western US.

      What is the cost?

      Extensive field and laboratory work required. Conservative estimated cost is about $180,000 (time, travel, analyses). Once fully quantified, additional cost for integration into soil survey standards and interpretations would be incurred.
       

    5. Oxyaquic Subgroup for Fragiudults – Kevin Godsey, Ken Scheffe (PDF; 183 KB)

      What is the issue?

      Oxyaquic subgroup is not provided for in Fragiudults, though it is provided for in the Fragiudalfs. A request to add Oxyaquic subgroup to Fragiudults was made in the past but not approved.

      What is the fix?

      Need the reason for not being approved and determine whether it is warranted. If warranted, add the Oxyaquic Fragiudults subgroup based upon known and described occurrence of soils meeting the class. Need to evaluate whether additional subgroups exist and are needed.

      What is the cost?

      Some fieldwork and review of the laboratory characterization data and pedon descriptions maybe needed.