Lecture 5b, 6, & 7a: Soils I, II, & III Spring 2007 WVU GEOL 321 (J.S. Kite) Soil: Assemblage of natural bodies on the Earth’s surface (natural or artificial) capable of supporting plant life outdoors Pedon: Area on Earth’s surface w/ single type of soil Also: soil mapping unit. NSF-REU program "A Field-Based Study of Landscape Evolution in Western Colorado." Mesa State College is recruiting undergraduate Geology students for 2007 summer Provide undergraduate students (sophomore or junior standing in Fall 2007 preferred; students who WILL NOT graduate by Spring 2008) with opportunity to gain research experience. 8 weeks (May 21-July 13) training, field work, & data compilation. Students will present results of their research at 2007 GSA meeting in Denver. No course prerequisites, but would like students to have completed at least Physical and Historical Geology. Each student will receive a stipend ($2400 for the 8 wk period), housing, a meal allowance (~$1,000), & round-trip travel to & from Grand Junction, CO. Also a $600 travel allowance to attend the GSA meeting in Denver, CO (Oct 28-31, 2007 ). 1 Soil Development Is a Function of 5 Factors S = ƒ (Cl,O,R,P,T) 1. Climate 2. Organisms 3. Relief 4. Parent material 5. Time Factors of Soil Development 1. Climate Temperature & Moisture Affect Eh & Redox Reactions Fe (Iron) Depletions Gray Reduced Iron (Water-Logged) Fe (Iron) Concentrations Red “Mottles” of Oxidized Iron (= Redoximorphic features) Factors of Soil Development 2. Organisms - Microorganisms (Bacteria, Fungi) Decompose organic material into humus Macroorganisms Bioturbation by Trees, Worms, Crayfish, Groundhogs, Gophers, Grizzly Bears Organisms Supply material Leaves (Conniferous vs. Deciduous Forests) Roots (Grasslands) 2 Factors of Soil Development 3. Relief Slope Steep Slopes: Well Drained, Erosion Low Slopes: Poorly Drained, Deposition Aspect Direction slope faces affects temperature & moisture Factors of Soil Development 4. Parent Material Material from which soil develops Types of Parent Material Residual Soil = Residuum Bedrock weathers in situ, on low relief & little erosion Parent Material, (cont.) Colluvial Transported by Gravity Alluvial Material Transported by Streams Glacial Transported by Glaciers Eolian Transported by Wind 3 Factors of Soil Development 5. Time Needed to Form Soils Depends on Other Factors Warm Climates Form Soil Faster Than Cold Biological & Geochemical Reactions Act 2X Faster for Every 10oC Increase Water = a ‘must’ in Pedochemical Reactions, Translocation Parent Material Affects Time to Form Soil Soil Properties Through Time Geometric Logarithmic Steady State Increasing Soil Development Increasing Time Soil Characteristics 1. Color Typically Formed by three substances 1. Humus Decomposed organic material 2. Iron (Fe) 3. Carbonate Munsell soil color chart 4 Soil Characteristics cont. 2. Texture (USDA) = size of soil particles in “matrix” Sand = 2.0 to 0.05 mm Silt = 0.05 to 0.002 mm Clay = less than 0.002 mm Excludes particles >2 mm Loam = Significant percentage of all three (2 sand: 2 silt: 1 clay) Soil Characteristics cont. Textural Triangle Texture determined by two methods 1. Particle Size Analysis Laboratory method 2. By Feel (Field method) Takes lots of practice High clay content will cause soil to form ribbon when rolled. 100 0 90 1 Soil P 0 e r 2 c 80 e Texture n t 0 S 3 70 il Triangle t Clay 0 60 4 0 5 50 Silty 0 y Sandy Clay 6 la 40 Clay C Silty Clay 0 t 7 n Clay Loam e 30 Loam c Sandy Clay r e Loam 0 P 8 20 Loam 0 Silt Loam 9 10 Lo Sandy Loam am y S 0 an Silt 0 Sand d 1 10 90 80 70 60 50 40 30 20 10 0 Percent Sand 5 Soil Characteristics cont. 3. Soil Structure PEDS: aggregates of particles Types of Structure Blocky (well developed) Platy Prismatic Columnar Granular (high organics) Soil Horizons Soil Profile Described from the surface down Solum “True soil” = A &/or E & B horizons Soil & Ground Water Distribution Eastern USA • Soil Moisture Belt • Unsaturated (= Vadose = Aeration) Zone Capillary Fringe • Water Table • Saturated (= Phreatic) Zone 6 Soil & Ground Water Phreatophytes Distribution Western USA • Soil Moisture Belt • Unsaturated (= Vadose = Aeration) Zone Capillary Fringe • Water Table • Saturated (Phreatic) Zone Soil Horizons Idealized Soil Profile L Horizon Leaf Litter Surface O Horizon Decomposed Organics A Horizon Top Soil E Horizon Leached Horizon Solum = A, E, and B { B Horizon Subsoil C Horizon Weathered (?) Parent Material R Horizon Bedrock Soil Horizons cont. L = New leaf litter In forest soils O = Organic Layer Partly decomposed organic matter A = Top Soil Mix of inorganic & organic material Eluvial horizon Most fertile soil horizon 7 Soil Horizons cont. E = Eluvial Horizon Organics & minerals even more elluviated, light color horizon B = Subsoil Illuvial horizon High clay content? Maximum soil development Soil Horizons (cont.) C = “Weathered” Parent Material or “Unweathered” Transported Material Has NOT undergone soil formation R = Bedrock Unweathered Bedrock Diagnostic Horizons EPIPEDONS Mollic: dark, > 1% O.M. in upper 7”, >50% base saturation Ochric: light, < 1% O.M. Umbric: dark, <50% base saturation Histic: peaty surface layer Plaggen: >20” of manure applied over long time 8 Diagnostic Horizons cont. SUBSURFACE HORIZONS Spodic: buildup of humus Argillic: buildup of clay Cambic: incomplete argillic or spodic horizon Oxic: high clay, 1:1 clay, low CEC Petrocalcic: Concentration of carbonates Albic: light colored E horizon Other Common Soil “Horizons” Fragipan: brittle layer with high bulk density Saprolite: soil mineralogy w/ relict bedrock structure Fragipan:Top view of truncated soil - Canaan Valley Btx horizon J.S. Kite Photo Fragipan: Side view showing reduced tongues J.S. Kite Photo 9 Subdivisions of Horizons: •A • B “1” not written •B2 •B3 •BC • 2 BC Change in Parent Material •2 C • 3 C Change in Parent Material lower case notations to horizons: • Ap p = disturbed (plowed?) A • Bw w = incipient (weak) B •C • Ab b = buried A • Bt t = argillic clay build-up •BC •C Catena Sequence of soils of about the same age, derived from similar parent material, and occurring under similar climate conditions, but having different characteristics due to variation in relief and in drainage. SSSA Internet Glossary of Soil Science Terms http://www.soils.org/sssagloss/ 10 Catena, Alberta www.soils.rr.ualberta.ca/soa/catena3.cfm Fourth Annual Student Night joint meeting of the Association of Engineering Geologists, the Pittsburgh Geological Society, and the Geotechnical Group of the Pittsburgh Section of the American Society of Civil Engineers. CALL FOR ABSTRACTS! Students are invited to submit abstracts (no more than 350 words) of a Senior Research Project, Senior Design Project, Master’s or PhD Thesis on the following topics : Geology, Engineering Geology, Geotechnical Engineering, Environmental Engineering, Hydrogeology, Hydrology Three students will be selected to give a 15-20 minute oral presentation based on their abstract submittal. Students not selected to give an oral presentation will be invited to present a poster summarizing their work. The students selected to give oral presentations will receive $100 awards. All students who present their research will receive a membership into PGS. Meeting Logistics April 18, 2007 6:00 p.m. Foster’s Restaurant, Foster Plaza Bldg. 10, Green Tree, PA THE DUE DATE FOR ABSTRACT SUBMITTAL IS MARCH 9, 2007. Notification will be given to the selected speakers on March 16, 2007. Abstracts may be submitted via email to [email protected]. If you have any questions or require a mailing address for abstract submittal please call Wendell Barner at 412-208-2409. Soil and Soil Development Soil Handout 11 Soil Taxonomy 6 Levels of Classification Order Suborder Great Group Subgroup Family Series Soil Taxonomy “Tucker County Mine Soil” Loamy-skeletal, mixed, acid, frigid Typic Udorthent ent = Entisol (ent as in recent) [Soil Order] orth = Common (typical entisol) [Suborder] Ud = Humid climate [Great Group] Typic = Common (typical udorthent) [Subgroup] frigid = Cold climate acid = pH less than 4.0 mixed = mixed mineralogy of materials in the soil skeletal = greater than 35% rock fragments in soil Loamy = textural classification = LOAM ORDER FORMATIVE ELEMENT Entisol ent no horizons Inceptisol ept incipient horizons - Cambic horizon Alfisol alf argillic horizon, high B.S. >35% Ultisol ult argillic horizon, low B.S. <35% Oxisol ox oxic horizon Mollisol oll mollic epidedon Spodosol od spodic horizon Vertisol ert shrink-swell soils Aridisol id dry >50% of year Histosol ist >30% organic matter Andisols and tephras Gelisols el permafrost 12 Suborder Formative Elements • Alb - White Albino • Aqu - Wet • Arg - Argillic Horizon • Ferr - Iron • etc. Examples of Suborders (2 Formative Elements): • Albolls - Albic Horizon • Aquolls - Wet (Aqueous) • Rendolls - Rendzina (Lots O. M. + Hi pH) • Xerolls - Xeric Dry Season • Borolls - Boreal Cool Mon-Marion County Soil Survey • See P. 157 13 West Virginia State Soil (1997) Monongahela feet Silt Loam Fine-loamy, mixed, semiactive, mesic Typic Fragiudults Source of image & text for 2 slides: www.statlab.iastate.edu/soils/ photogal/statesoils/wv_soil.htm Monongahela soils occur on >100,000 acres in 45 counties in West Virginia. These very deep, moderately well- drained soils are on alluvial or glacial- lake terraces (after NRCS w/ JSK modif.) Generalized Distribution TYPE LOCATION: 2.7 mi E of Beverly, 100 ft N of church on N boundary of 4-H Camp, Randolph Co., WV; MLRA OFFICE: Morgantown, WV SERIES ESTABLISHED: Greene County, Pennsylvania, 1921. DIAGNOSTIC HORIZONS, etc. Ochric epipedon - 0 to 12 inches (Ap & BA horizons). Argillic horizon - 12 to 22 inches (Bt horizon). Fragipan - 22 to 52 inches (Btx horizon). Source of image and text for 3 slides: www.statlab.iastate.edu/soils/ osd/dat/M/MONONGAHELA.html 14 Ap--0 to 7 inches; dark grayish brown (10YR 4/2) silt loam; moderate fine granular structure; friable; many roots; slightly acid; abrupt smooth boundary. (6 to 10 inches thick) BA--7 to 12 inches; yellowish brown (10YR 5/4) silt loam; weak fine subangular blocky structure; friable; common roots; slightly acid; clear smooth boundary.