Summary of Changes to

Keys to Soil Taxonomy

May, 2006

Chapter and page numbers refer to

Keys to Soil Taxonomy, ninth edition, 2003.

# Chapter 3 -- Horizons and Characteristics Diagnostic for the Higher Categories 

-   [Anthropic epipedon]{.underline}, P. 13 -- Revised the definition so
    that it now stands on it's own rather than referring to the mollic
    epipedon.

-   [Plaggen epipedon]{.underline} , P. 15 -- Definition expanded to
    include a list of required characteristics.

-   [Mollic and Umbric epipedons,]{.underline} P. 14 & 15. Minor edits
    for clarification of criteria with no change in intended meaning.

-   [Calcic and Gypsic horizons]{.underline} , P. 17 & 19 -- Revised to
    more clearly describe the degree of cementation allowed.

-   [Anhydrous Conditions]{.underline} -- P. 22 - Definition expanded to
    include a list of required characteristics.

-   [Andic Soil Properties]{.underline}, P. 22 - Revised and expanded
    the introductory paragraph. Edits made to required characteristics
    section for clarification (no change to meaning), and corrected
    error in syntax of equation.

-   [Volcanic Glass]{.underline}, P. 26 -- This is a new item added to
    the list of "Other Diagnostic Soil Characteristics" section (after
    "Spodic Materials").

-   [Ustic Moisture Regime,]{.underline} P. 33 -- Corrected error in
    definition that prohibited it's use with the cryic soil temperature
    regime.

# Chapter 5 -- Alfisols

-   [Mollic & Umbric subgroups.]{.underline} -- References to Ap
    horizons in the keys are changed to specify mixing to 18 cm.

# Chapter 6 -- Andisols

-   [Duricryands]{.underline} -- P 87, Add 2 new subgroups:

-   Eutric Oxyaquic

-   Oxyaquic

# Chapter 8 -- Entisols

-   [Mollic & Umbric subgroups.]{.underline} -- References to Ap
    horizons in the keys are changed to specify mixing to 15 cm.

**Chapter 10 -- Histosols**

-   Cryosaprists, P. 162, add new subgroup:

-   Limnic

# Chapter 11 -- Inceptisols

-   **[Mollic & Umbric subgroups.]{.underline} -- References to Ap
    horizons in the keys are changed to specify mixing to 15 cm.**

-   [Cryepts]{.underline} -- P. 171, Major revisions to this great
    group.

    -   Delete Eutrocryepts

    -   Establish 3 new great groups

    -   Humicryepts, with 15 subgroups

    -   Calcicryepts, with 5 subgroups

    -   Haplocryepts, with 17 subgroups

    -   Revise the existing Dystrocryepts

    -   Delete Humic, and Humic-Lithic subgroups.

    -   Add 6 new subgroups

-   [Sulfaquepts]{.underline} -- P. 171, Corrected error in item number
    one for Hydraquentic subgroup to require 8 or more percent clay.

-   [Durudepts]{.underline} -- .P 174, Criteria revised to allow
    cemented layers in addition to Duripans.

# 

# Chapter 17 -- Families and Series Differentiae and Names

-   [Key to Particle-size Classes]{.underline}, P. 300:

-   Correct error in item B.2. that effectively prevented keying beyond
    the medial classes to the hydrous classes.

-   [Strongly Contrasting Particle-size Classes]{.underline}, P. 301.

-   Add 3 new classes.

-   Ashy-skeletal over sandy or sandy-skeletal.

-   Medial-skeletal over sandy or sandy-skeletal.

-   Pumiceous or ashy pumiceous over loamy-skeletal.

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-   [Key to mineralogy classes]{.underline}, P. 303

-   Revise keying order to allow micaceous and paramicaceous to key out
    before parasesquic.

-   Several minor editorial revisions for clarification, with no change
    in meaning.

# Chapter 18 -- Designations for Horizons and Layers 

# [Revisions to reflect changes to Horizon nomenclature resulting from ICOMANTH, P. 313.]{.underline} 

-   New master horizon "M", for manufactured layers.

-   New subscript "u", for layers containing artifacts.

-   New prefix \^ for layers formed in human transported materials.

**Appendix**

-   Revised as needed to coordinate terms for laboratory procedures with
    the Laboratory Methods Manual, SSIR #42.

-   Added headings for "Physical Analyses", "Chemical Analyses", and
    "Mineral Analyses".

    -   Items under chemical analyses arranged alphabetically.

-   ODOE added under chemical analyses.

-   Mineral analyses discussion revised and expanded.