Soils Classified (USDA System)

1. Soils Classified (USDA System) • Terminology a. class: A group of individuals that are similar in selected properties. b. category: A group of classes. c. hierarchical system: A system having a number of categories differing in level of generalization, such that each class within a category is also a subclass of a class within any higher category.

4. Formative Elements: Syllables used to designate classes – Order through Great Group • Formative elements for Orders are as follows: • Alfisols - alfInceptisols - ept • Andisols – and Mollisols - oll • Aridisols – id Oxisols - ox • Entisols – ent Spodosols - od • Gelisol – el Ultisols - ult • Histosols – ist Vertisols - ert

8. 5. Soil Orders that occur in Florida Histosols - Dominated by organic soil material Spodosols - Have Spodic. May have Argillic Mollisol - Have Mollic & BS ≥ 50%. May have Argillic Alfisols - Have argillic and BS ≥ 35% in lower part Ultisol -Have argillic and BS < 35% in lower part Inceptisol - Have Umbric or Histic (in some cases Mollic) Entisol - Default. Absence of most diagnostic horizons to 2 m

9. 6. Categories & Nomenclature Examples Examples of Entisol Great Groups • Suborder • Aquents • (Wet Entisols) • Great Groups • Cryaquents - cold • Fluvaquents - floodplain • Hydraquents - water • Psammaquents - sand • Epiaquents - perched

10. Examples of Entisol Great Groups • Suborder • Fluvents • (Floodplain soils) • Great Groups • Torrifluvents - torrid • (hot and dry) • Tropofluvents - tropical • (warm and humid) • Udifluvents - humid • (not dry in most years) • Ustifluvents - semi-arid • (between Udic-Aridic) • Xerofluvents - semi-arid • (Mediterranean climate)

11. Examples of Entisol Great Groups • Suborder • Psamments • (Sandy Soils) • Great Groups • Cryopsamments • Quartzipsamments - Quartz • Torripsamments • Udipsamments • Ustipsamments • Xeropsamments

12. Examples of Subgroups 4 3 2 1 Typic Fluvaquents 4 1 2 Typical Entisols with aquic moisture regimes 3 that occur on floodplains. 1. Order 3. Great Group 2. Suborder 4. Subgroup(the typical concept of Fluvaquents

13. Examples of Subgroups 4 3 2 1 Mollic Fluvaquents 1 2 Entisols with aquic moisture regimes that 3 occur on floodplains and have thick, 4 dark surface layers. 1. Order 3. Great Group 2. Suborder 4. Subgroup(intergrading toward a Mollisol)

14. Examples of Subgroups 4 3 2 1 Aeric Fluvaquents 1 3 2 Entisols on floodplains with aquic moisture regimes that are not so wet. They are better 4 aerated in the “upper” part of the soil profile. 1. Order 3. Great Group 2. Suborder 4. Subgroup(intergrading toward a more aerated subgroup)

15. Aquic Soil Moisture Regimes • Typic subgroup of an aquic suborder: • Typic ____aqu____ • wettest • Aeric subgroup of an aquic suborder: • Aeric ____aqu____ • better aerated • Aquic subgroup: • Aquic ___________ • driest From Mausbach 1992

16. Nature of Number Differentiating Category of Taxa Characteristics Family Many The Family name consists of a series of descriptive names that modify the subgroup name. Note: since the family name adds no knowledge to our understanding of wet soils the family level of soil classification will not be discussed.

17. Nature of Number Differentiating Category of Taxa Characteristics Series 17,000+ May have virtually the full range of properties that is permitted in a family, but in one or more properties the range is restricted. Note: since the series name adds no knowledge to our understanding of wet soils it the series level of soil classification will not be discussed.

18. 7. Practice Typic Haplosaprists

19. Typic Haplosaprists • What does the taxonomic classification mean? • Is it likely, not likely, or maybe hydric? • Histosol dominated by sapric material (wet). • Likely to be hydric. Large areas of this soil converted to crop land in south Florida.

20. Aquic Paleudalfs

21. Aquic Paleudalfs • What does the taxonomic classification mean? • Is it likely, not likely, or maybe hydric? • Alfisol with aquic conditions moderately deep in profile. • Likely to be nonhydric. Has water table in E horizon for brief periods during high rainfall. In an aquic subgroup.

22. Aquic Quartzipsamments

23. Aquic Quartzipsamments • What does the taxonomic classification mean? • Is it likely, not likely, or maybe hydric? • Entisol that is sandy, dominated by quartz sand, with aquic conditions moderately deep in profile. • Likely to be a nonhydric soil. In an aquic subgroup. Seasonal high water table at about 24 inches.

24. Typic Argiaquolls

25. Typic Argiaquolls • What does the taxonomic classification mean? • Is it likely, not likely, or maybe hydric? • Mollisol with aquic conditions near surface and accumulation of clay in subsoil. • Likely to be hydric. Hydric soils commonly classify in an aquic suborder; “argi” is “double whammy” (will explain).

26. Aeric Alaquods

27. Aeric Alaquods • What does the taxonomic classification mean? • Is it likely, not likely, or maybe hydric? • Spodosol with aquic conditions near surface; not quite as wet as “typic” subgroups. • Maybe hydric. Typical Spodosol on flatwoods. In an aquic suborder.

28. Class as Likely Hydric, Maybe Hydric, or Likely Non-Hydric • Typic Haplosaprists Terric Haplosaprists • Lithic Cryofolists Aquic Paleudalfs • Aquic Glossudalfs Typic Aquisalids • Aquic Quartzipsamments Typic Humaquepts • Typic Argiaquolls Argiaquic Argialbolls • Aeric Calciaquolls Aeric Alaquods • Typic Umbraquults Chromic Epiaquerts

29. Answers According to Hurt • Likely Hydric • Typic Haplosaprists Terric Haplosaprists • Typic Humaquepts Typic Umbraquults • Typic Argiaquolls Typic Aquisalids • Chromic Epiaquerts Argiaquic Argialbolls • Maybe Hydric • Aeric Calciaquolls Aeric Alaquods • Likely Nonhydric • Aquic Glossudalfs Aquic Paleudalfs • Aquic Quartzipsamments Lithic Cryofolists

30. Summary • Likely Hydric: Soils in the Albolls Suborder or soils with a formative element at the Suborder level of soil classification (Aqu, Fibr, Hist, and Sapr.), unless they have the formative element aeri at the suborder level and soils in the following Great Groups Aquisalids, Historthels, and Histoturbels. • Maybe Hydric: Soils with a a formative element at the Suborder level of soil classification (Aqu, Fibr, Hist, and Sapr.) and the formative element aeri at the suborder level and soils on flood plains such as Aquic Dystrochrepts, Aquic Eutrochrepts, and Aquic Udifluvents. • Likely Nonhydric: Soils with all other classifications including aqu at the Subgroup level of soil classification with some exceptions (note the three example given above).