Soil Taxonomy and Classification

1. Soil Taxonomy and Classification

2. Soil Taxonomy Hierarchy Kingdom Phylum Class Order Family Genus Species Order Suborder Great group Sub group Family Series 12 63 250 1400 8000 19,000

3. Diagnostic Surface Horizons Epipedons Mollic Umbric Ochric Histic Melanic Plaggen Anthropic Very common “specialized” Human-derived

4. Organic Matter Accumulation Histic Mollic, Umbric ochric O.M. accumulation time Parent material Vegetation established tmax = 3000 yrs

5. Diagnostic Sub-surface Horizons

6. Diagnostic SubsurfaceHorizons Formation Translocation Transformation Clays Organic Matter Oxides

7. Subsurface Horizons Formation Translocation Transformation Organic Matter Clays Oxides smectites Dark colors Metals (Fe, Al) Iron Aluminum Kaolinite Also: salts, carbonates, sulfides

8. Diagnostic Subsurface Horizons Natric Agric Calcic Gypsic Salic Duripan Fragipan Placic Albic Argillic Spodic Oxic Kandic Cambic Sombric sulfuric Subordinate Distinctions

9. Diagnostic Subsurface Horizons Albic (white) Horizon Light-colored (Value > 6 moist ) Elluvial (E master horizon*) Low in clay, Fe and Al oxides Generally sandy textured Low chemical reactivity (low CEC) Typically overlies Bh or Bt horizons albic *not all E horizons are albic horizons

10. Diagnostic Subsurface Horizons Argillic Horizon Illuvial accumulation of silicate clays Illuvial based on overlying horizon Clay bridges Clay coatings Bt horizon

11. Diagnostic Subsurface Clay Horizons Argillic Horizon Kandic Horizon Low High Activity of Clays Not Necessary Necessary Illuviation of clay

12. Diagnostic Subsurface Horizons Spodic Horizon • Illuvial accumulation of organic matter • and aluminum (+/- iron) • Dark colored (value, chroma < 3) • Low base saturation (acidic) • Formed under humid acid conditions Spodic Bh horizon

13. Elluviation and Illuviation Elluviation (E horizon and A horizons) Organic matter Clays A Bt A E Bh E Bh horizon Bt horizon Argillic horizon Spodic horizon

14. Diagnostic Subsurface Horizons Oxic horizon • Highly weathered (high temperatures, high rainfall) • - High in Fe, Al oxides • - High in low-activity clays (kaolinite < smectite < vermiculite) activity Bo horizon

15. Diagnostic Horizons Surface Horizons: Mollic- thick, dark colored, high %B.S., structure Umbric – same, but lower B.S. Ochric – pale, low O.M., thin Histic – High O.M., thick, wet, dark Sub-Surface Horizons: Argillic – illuvial accum. of clay (high activity) Kandic – accum. of clay (low activity) Spodic – Illuvial O.M. accumulation (Al and/or Fe) Oxic – highly weathered, kaolinite, Fe and Al oxides Albic – light colored, elluvial, low reactivity

16. Soil Taxonomy Diagnostic Epipedons Diagnostic Subsurface horizons Moisture Regimes Temperature Regimes Age Texture Depth

17. Soil Orders Soil forming processes, presence or Absence of major diagnostic horizons Similar genesis Order Suborder Great group Sub group Family Series 12 63 Grasslands – thick, dark epipedons High %B.S. 250 1400 8000 19,000

18. Soil Orders Entisols Histosols Inceptisols Andisols Gelisols Alfisols Mollisols Ultisols Spodosols Aridisols Vertisols Oxisols

19. Soil Orders Ent- Hist- Incept- Alf- Ult- Spod- Moll- Ox- And- Gel- Arid- Vert- Recent Histic (organic) Inception Television alien Ultimate Spodos (wood ash) Mollis (soft) oxide Ando (black) Gelid (cold) Arid (dry) Verto (turn) Entisol Histosol Inceptisol Alfisol Ultisol Spodosol Mollisol Oxisol Andisol Gelisol Aridisol Vertisol

20. Soil Orders in Florida • Entisols – little development, usually A-C horizons, ochric epipedon • Inceptisols – A little more development, Bw horizons, ochric, umbric epipedon • Alfisols – Argillic/Kandic horizon (Bt) less than 2 m, base saturation is > 35% • Ultisols – Argillic/Kandic horizon (Bt) less than 2 m, base saturation is < 35% • Mollisols – Mollic epipedon, dark, high organic matter • Spodosols – Spodic horizon (Bh), ochric, umbric epipedon • Histosols – Organic soil, histic epipedon Entisols Inceptisols Alfisols Ultisols Mollisols Spodosols Histosols 0 A A A A A O A E C Bw E E Bt Bw Bt Bh meters C C C C C 2

21. Entisols Young Soils Weaklly developed Sandy or clayey Ochric Epipedon A – C profiles

22. Taxonomic Peculiarity A horizon C horizon 2 meters (200 cm) Bt

23. Entisols

24. Inceptisols Ap horizon Little Development Ochric, Histic, or Umbric epipedon One or more subsurface horizons Weakly developed Contains many unweathered minerals Bw horizon C horizon

25. Histosols • Peat or muck • > 20% organic matter • Agriculturally valuable • Sometimes used as fuel • Often over impermeable material

26. Histosols

27. Alfisols Mollic/Umbric/Ochric epipedon A horizon E horizon Bt horizon (argillic, kandic) base saturation > 35% Btg horizon

28. Ultisols A horizon E horizon Bt horizon Mollic/umbric/Ochric epipedon Argillic or Kandic horizon Base saturation < 35%

29. Ultisols and Alfisols Mixed Hardwood Forests

30. Spodosols Associated with acidic vegetation Subsoil accumulation of organic matter with aluminum and/or iron Formed under Wet acidic conditions Poorly or Very poorly drained Pine Flatwoods State Soil of Florida

31. Spodosols Pine Flatwoods (wet, acidic)

32. Mollisols Mollic Epipedon High organic matter Thick surface horizon Highly productive Many with argillic Poorly-drained Surface % B.S. > 50%

33. Mollisols Grasslands

34. Soil Orders Weathering and development slight Strong Entisols Histosols Inceptisols Andisols Gelisols Aridisols Vertisols Alfisols Mollisols Ultisols Spodosols Oxisols

35. Geographic Distribution

36. Florida Soil Orders Spodosols 8.4 million acres Entisols 7.5 Ultisols 6.9 Alfisols 4.6 Histisols 4.0 Inceptisols 1.0 Mollisols 1.0

37. Soil Taxonomy Order Suborder Great group Sub group Family Series 12 Soil forming processes / diagnostic horizons Genetic similarity: Wetness, climate, vegetation 63 250 1400 8000 19,000

38. Moisture Conditions Wet Dry Aquic – poor aeration, reduced iron Udic- dry < 90 total days Ustic - limited but is present Aridic- moist <90 total days Xeric - dry Temperature Conditions cold Hot Cryic – icy cold Frigid – lower than 8oC Mesic – between 8 and 15oC Thermic – between 15 and 22oC Hyperthermic - > 22oC

39. Suborders Temperature, moisture, diagnostic horizons Suborder Examples Aquod verywet spodosol Udult wet ultisol Udoll wet mollisol Xeroll dry mollisol Ochrept Umbrept alboll

40. Soil Taxonomy Order Suborder Great group Sub group Family Series 12 Soil forming processes / diagnostic horizons Soil moisture conditions, diagnostic horizon Arrangement of Diagnostic horizons 63 250 1400 8000 19,000

41. Great Groups Based on diagnostic horizons and their arrangements or other features like age, color, texture Arg - argillic horizon present Pale - old Kand - kandic horizon present Hapl - minimum horizonation quartzi – quartz sand Hum - humid

42. Greater Specificity SuborderGreat Group Udult paleudult Aquoll argiaquoll Udalf paleudalf Udult hapludult Order Ultisol Mollisol Alfisol Ultisol

43. Sub group Expresses the core concept of the great group Moisture, sandiness, depth, color Typic shallow sand Arenic deeper sand Grossarenic deep sand Aquic Typic hapludult Grossarenic quartzipsamment suborder Subgroup Great group order

44. Families Properties important to growth of plant roots Particle sizemineralogytemperature oC Siliceous Kaolinitic Smectitic Oxidic Sandy Loamy Fine loamy Clayey Frigid < 8 Mesic 8-15 Thermic 15-22 Hyperthermic > 22

45. Series Horizon number, order, thickness, texture, structure, Color, Organic matter, pH, accumulations Order Sub-order G. Group Sub-group Family Series Mollisol Aquoll Argiaqoll typic Argiaquoll typic argiaquoll Brookston loamy siliceous Cordova Westland

46. Alachua County Apopka loamy, siliceous, hyperthermic grossarenic paleudult Ledwith fine, smectitic, hyperthermic mollic albaqualf Surrency loamy, siliceous, thermic, arenic paleaquult Pomona sandy, siliceous, hyperthermic, ultic, haplaquod paleudult order Suborder great group sub-group family albaqualf paleaquult haplaquod

47. Alachua County paleudult Great group suborder order albaqualf Great group suborder order