Lecture 16 Morphology and Orders.ppt
- 1. Soil Taxonomy and Classification
- 2. Order Suborder Great group Sub group Family Series 12 19,000 Soil Taxonomy Hierarchy 63 250 1400 8000 Kingdom Phylum Class Order Family Genus Species
- 3. Diagnostic Surface Horizons Epipedons Mollic Umbric Ochric Histic Melanic Plaggen Anthropic Very common Human-derived “specialized”
- 4. Vegetation established O.M. accumulation time Organic Matter Accumulation Histic Mollic, Umbric ochric Parent material tmax = 3000 yrs
- 6. Diagnostic Subsurface Horizons Clays Organic Matter Oxides Formation Translocation Transformation
- 7. Organic Matter Clays Oxides smectites Subsurface Horizons Kaolinite Also: salts, carbonates, sulfides Dark colors Metals (Fe, Al) Iron Aluminum Formation Translocation Transformation
- 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. Argillic Horizon Illuvial accumulation of silicate clays Illuvial based on overlying horizon Clay bridges Clay coatings Diagnostic Subsurface Horizons Bt horizon
- 11. Diagnostic Subsurface Clay Horizons Argillic Horizon Kandic Horizon Activity of Clays High Low Illuviation of clay Necessary Not Necessary
- 12. Diagnostic Subsurface Horizons Spodic Horizon Spodic • Illuvial accumulation of organic matter and aluminum (+/- iron) • Dark colored (value, chroma < 3) • Low base saturation (acidic) • Formed under humid acid conditions Bh horizon
- 13. Elluviation (E horizon and A horizons) Organic matter Clays Spodic horizon Bh horizon Bt horizon Argillic horizon Elluviation and Illuviation A E Bh A Bt E
- 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. 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 Diagnostic Horizons
- 16. Soil Taxonomy Diagnostic Epipedons Diagnostic Subsurface horizons Moisture Regimes Temperature Regimes Age Texture Depth
- 17. Order Suborder Great group Sub group Family Series 12 19,000 Soil Orders Soil forming processes, presence or Absence of major diagnostic horizons Similar genesis 63 250 1400 8000 Grasslands – thick, dark epipedons High %B.S.
- 19. Soil Orders Entisol Histosol Inceptisol Alfisol Ultisol Spodosol Mollisol Oxisol Andisol Gelisol Aridisol Vertisol 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)
- 20. Soil Orders in Florida E Bt C A C O C Bw C Bw E Bh C Bt E •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 0 2 A A A A A C Entisols Inceptisols Alfisols Ultisols Spodosols Mollisols Histosols meters
- 21. Entisols Young Soils Weaklly developed Sandy or clayey Ochric Epipedon A – C profiles
- 22. Taxonomic Peculiarity 2 meters (200 cm) A horizon C horizon Bt
- 23. Entisols
- 24. Inceptisols Little Development Ochric, Histic, or Umbric epipedon One or more subsurface horizons Weakly developed Contains many unweathered minerals Bw horizon Ap 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 A horizon E horizon Bt horizon (argillic, kandic) base saturation > 35% Mollic/Umbric/Ochric epipedon 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%
- 34. Soil Orders Entisols Histosols Inceptisols Andisols Gelisols Aridisols Vertisols Alfisols Mollisols Ultisols Spodosols Oxisols slight Strong Weathering and development
- 36. Spodosols 8.4 million acres Entisols 7.5 Ultisols 6.9 Alfisols 4.6 Histisols 4.0 Inceptisols 1.0 Mollisols 1.0 Florida Soil Orders
- 37. Order Suborder Great group Sub group Family Series 12 19,000 Soil Taxonomy Soil forming processes / diagnostic horizons Genetic similarity: Wetness, climate, vegetation 63 250 1400 8000
- 38. Wet Dry Moisture Conditions Aquic – poor aeration, reduced iron Udic- dry < 90 total days Ustic - limited but is present Aridic- moist <90 total days Xeric - dry cold Hot Temperature Conditions Cryic – icy cold Frigid – lower than 8oC Mesic – between 8 and 15oC Thermic – between 15 and 22oC Hyperthermic - > 22oC
- 39. Suborder Examples Suborders Temperature, moisture, diagnostic horizons Aquod very wet spodosol Udult wet ultisol Udoll wet mollisol Xeroll dry mollisol Ochrept Umbrept alboll
- 40. Order Suborder Great group Sub group Family Series 12 19,000 Soil Taxonomy Soil forming processes / diagnostic horizons Soil moisture conditions, diagnostic horizon Arrangement of Diagnostic horizons 63 250 1400 8000
- 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. Suborder Great Group Udult paleudult Aquoll argiaquoll Udalf paleudalf Udult hapludult Order Ultisol Mollisol Alfisol Ultisol Greater Specificity
- 43. Sub group Expresses the core concept of the great group Moisture, sandiness, depth, color Typic hapludult Grossarenic quartzipsamment Typic shallow sand Arenic deeper sand Grossarenic deep sand Aquic order suborder Great group Subgroup
- 44. Families Properties important to growth of plant roots Particle size mineralogy temperature oC Sandy Loamy Fine loamy Clayey Siliceous Kaolinitic Smectitic Oxidic Frigid < 8 Mesic 8-15 Thermic 15-22 Hyperthermic > 22
- 45. Series Horizon number, order, thickness, texture, structure, Color, Organic matter, pH, accumulations Mollisol Aquoll Argiaqoll typic Argiaquoll typic argiaquoll Brookston loamy siliceous Cordova Westland Order Sub-order G. Group Sub-group Family Series
- 46. 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 albaqualf paleaquult haplaquod order Suborder great group sub-group family Alachua County
- 47. paleudult albaqualf Great group suborder order Alachua County Great group suborder order