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Figure 4. Piper diagram, red highlights the lake samples and blue highlights the seep samples for the month of January 2006. The green represents the lake samples from May and the yellow are the seep samples from May 2006.
Seep - JanuaryLake - January
Seep - MayLake - May
2006 Data
Maximum Growth
WinterConditions
Macrophyte DecayInitial Advanced Post
July August September October
0 21 51 65 98 119Experimental Days after Landers, 1982
N P
C
N
PC
Macrophyte Decay Cycle
Geology
Archaeology
Climatology
Hydrology
Engineering
Geomorphology
Pedology
Ecology
Biogeography
Soil science
Agriculture
Environmentalmanagement
SOILS
Soils can be studied in the context of may different disciplines:
Soils are a product of:• Climate (temperature, precipitation) influences the dominance of chemical or mechanical
weathering• Topography
slope and aspect affect the moisture and temperature of soil and influences the accumulation rate of soils
• Biologic activityaeration of the horizons, disruption of horizons by
bioturbation, open channels in the soils for water• Parent material(s)
defines the materials available for alteration and the source of materials for secondary, pedogenic minerals
• Timeallows for the development of the individual
• 10,000 to 50,000 years are required to form 1 meter of soil!
• Natural erosion rates are similar to rates of soil formation.
• Human activities have increased erosion rates by factors of 10 to 100.
• There has been a 32% decline in the amount of topsoil between 1984 and 2000.
Turbid sediment plumes along the California coast near Gaviota following storms of February 1998. Picture by Mark Defeo and used by permission. www.pubs.usgs.gov/sir/2007/5254/
Granite grus developed on Silurian granite.
O-Horizon: primarily decomposing organic matter with little mineral matter
A-Horizon: Zone of Leaching or Eluviation. Relatively loose and friable with organic matter
B-Horizon: Zone of Accumulation or Illuviation. Material leached from above.
C-Horizon: very little chemical weathering Cox: oxidation of C
R-Horizon: unweathered bedrock
Bt: clay and hydrated Fe and Al oxidesBk: accumulation of CaCO3; calicheBs: sesquioxides of Fe and Al and organic matterBh: mainly humus
Availability of Elements to Plants at Different pH levels
for Mineral SoilsMycorrhiza (Gk.: fungus roots)is a symbiotic (generally mutualistic, but occasionally weakly pathogenic) association between a fungus and the roots of a vascular plant.
Think of this as a globe where the outer equator represents the highest saturation of hue (color).
As you follow toward the center, the hue becomes de-saturated toward gray.
The "north pole" is lighter in value, whereas the "south pole" is darker in value
The system consists of three independent dimensions which can be represented cylindrically in three dimensions as an irregular color solid: hue, measured by degrees around horizontal circles; chroma, measured radially outward from the neutral (gray) vertical axis; and value, measured vertically from 0 (black) to 10 (white).
Iron oxides (Fe2O3) and hydroxides and alumno-ferric oxides/hydroxides (Fe2O3 + Al2O3)
Carbonates – white
Bare mineral grains Anaerobic (waterlogged) ------------------------------------------------Color described by:
hue value chroma
10 YR 4/6
Hue = dominant primary colorValue = lightness or darkness
Chroma = intensity/strength of color
– gray/gray green
– red/orange/yellow
UPa
LS
LUGLMG
LLG
MZ
UG
GSC
Alluvium
Color as environmental indicator:Lerna, Greece.
Soil Peds Graphic Example Description of Structure Shape
Granular – roughly spherical, like grape nuts. Usually 1-10 mm in diameter. Most common in A- horizons, where plant roots, microorganisms, and sticky products of organic matter decomposition bind soil grains into granular aggregates
Platy – flat peds that lie horizontally in the soil. Platy structure can be found in A-, B- and C- horizons. It commonly occurs in an A-horizon as the result of compaction.
Blocky – roughly cube-shaped, with more or less flat surfaces. If edges and corners remain sharp, angular blocky. If they are rounded, subangular blocky. Sizes commonly range from 5-50 mm across. Blocky structures are typical of B-horizons, especially with a high clay content. They form by repeated expansion/contraction of clay minerals.
Prismatic – larger, vertically elongated blocks, often with five sides. Sizes are commonly 10-100mm across. Prismatic structures commonly occur in fragipans. (L)Columnar – the units are similar to prisms and are bounded by flat or slightly rounded vertical faces. The tops of columns, in contrast to those of prisms, are very distinct and normally rounded. (R)
Terra Rosa (B horizon) developed on Mississippian carbonate.Prismatic peds are coated with white clays.
Key for Finger Assessment of Soil Texture
1. Does moist soil form a coherent ball? Easily ....(2) (With great care ....LOAMY SAND (but check using tests 2 and 3) No ....SAND2. What happens when ball is pressed between thumb and forefinger? Flattens coherently .... (3) Tends to break up ....SANDY LOAM (but check using tests 3 and 4)3. On slight further moistening, can the ball be rolled into a cylinder about 5 mm thick? Yes .... (5) No, collapses ....LOAMY SAND4. On slight further moistening, can the ball be rolled into a thread about 2 mm thick? Yes .... (5) No ....SANDY LOAM5. Can the thread be bent into a horseshoe without cracking, e.g. around the side of the hand? Yes ....(7) No .... (6)6. On remolding with further moisture, what is the general "feel" of the soil? Smooth and pasty ....SILT LOAM Rough and abrasive ....SANDY SILT LOAM7. Can a ring of about 25 mm diameter be formed by joining the two ends of the thread without cracking? (If necessary, remold with moisture and begin again.) Yes ....(9) No .... (8)8. On remolding with further moisture, what is the general "feel" of the soil? Very gritty ....SANDY CLAY LOAM Moderately rough ....CLAY LOAM Doughy ....SILTY CLAY LOAM9. On remolding without rewetting, can surface be polished with the thumb? Yes, a high polish like wax with few noticeable particles....(10) Yes, but gritty particles very noticeable ....SANDY CLAY 10. On wetting thoroughly, how strongly does the soil stick one's fingers together? Very strongly ....CLAY Moderately strongly ....SILTY CLAY
Soil Textures
Clay
SiltyClaySandy
Clay SiltyClay Loam
Clay Loam
LoamSilty Loam
Silt
SandyClay Loam
SandyLoamLoamy
SandSand
Sand Silt
Clay
Clay
SiltyClaySandy
ClaySiltyClay LoamClay Loam
Loam
Silty Loam
Silt
SandyClay Loam
Sand
Sand Silt
Clay
Loamy Sand
SandyLoam
analysis by finger test
analysis by sievingMontana soils developed on glacial till
Fig. 1. Map showing the distribution of loess in the central USA, location of pedons sampled, and last-glacial paleowinds (Muhs and Bettis, 2000). Peoria Loess distribution slightly modified from Thorp and Smith (1952); Bignell Loess distribution compiled by the authors using data from Caspall (1972), Martin (1993), Johnson (1993), Kuzila (1995), Pye et al. (1995), and Muhs et al. (1999).
Muhs, D.R., Bettis, III, E.A., Been, J. and McGeehin, J.P., 2001, Impact of Climate and Parent Material on Chemical Weathering in Loess-derived Soils of the Mississippi River Valley: Soil Sci. Soc. Am. J. 65:1761–1777.
Peoria Loess
N
Pleistocene
?
Muhs, D.R., Bettis, III, E.A., Been, J. and McGeehin, J.P., 2001, Impact of Climate and Parent Material on Chemical Weathering in Loess-derived Soils of the Mississippi River Valley: Soil Sci. Soc. Am. J. 65:1761–1777.
Figure 4. Muhs, D.R., Bettis, III, E.A., Been, J. and McGeehin, J.P., 2001, Impact of Climate and Parent Material on Chemical Weathering in Loess-derived Soils of the Mississippi River Valley: Soil Sci. Soc. Am. J. 65:1761–1777.
S
Northern Mississippi Valley and Southern Mississippi Valley Peoria loess samples, unweathered and unleached (this study). Southwestern Indiana data from Mount Vernon, IN section (Hayward and Lowell, 1993) and Western Iowa data from Loveland, Iowa (Muhs and Bettis, 2000).
Muhs, D.R., Bettis, III, E.A., Been, J. and McGeehin, J.P., 2001, Impact of Climate and Parent Material on Chemical Weathering in Loess-derived Soils of the Mississippi River Valley: Soil Sci. Soc. Am. J. 65:1761–1777.
The soil environment. Organisms live in the microscale environments within and between soil particles. Differences over short distances in pH, moisture, pore size, and the types of food available create a broad range of habitats. Credit: S. Rose and E.T. Elliott
Mycorrhizal fungi (top) live within the roots of most crop plants. Soil fungi (bottom) help decompose organic matter and form soil aggregates. Most soil fungi are beneficial, rather then pathogenic. www.midamericalandrestore.com
Total Carbon (TC) = Total Organic Carbon (TOC) + Total Inorganic Carbon (TIC)
TOC preparation:
• ~0.25 g dry, powdered sample• acidified in baked glass beaker with 1N HCl, @ 60 oC for 12-14 hours• filtered with de-ionized water to flush out Cl- onto a baked glass fiber filter• transferred to a crucible boat for drying and elemental analysis
Calcite
O2
sample
combustion tube
halogen trap
water trap
IR detectors
computer
OM + O2 CO2 + SO2
Elemental Analyzers
The detectors utilize solid state sensors combined with infrared filters.
Infrared (IR) radiation is part of the electromagnetic spectrum, which includes radio waves, microwaves, visible light, and ultraviolet light, as well as gamma rays and X-rays. The IR range falls between the visible portion of the spectrum and radio waves. IR wavelengths are usually expressed in microns, with the lR spectrum extending from 0.7 to 1000 microns (µm).