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scientific soil details
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Important/significant foundation soil physical properties
Color
Redoximorphic features
Texture
Structure
Consistence
Coarse fragments
Reaction
Important/significant foundation soil physical properties
Color not an influence, but an indicator and diagnostic resourceTexture the composition (sand, silt, clay), the feel, the classification (triangle) - microporesStructure how the particles are aggregated, bound together macroporesConsistence how the soil holds together, feels, can be worked when wet; assessing textureCoarse fragments rocks dont hold water!Soil reaction acid or base, leached or not leached, saturated or not saturatedoxidation = aerated
reduction = anaerobic, lacking oxygen
Carbonates, sulfates, chlorides affect color
Mottles, speckles, blotches alternating wet and dry conditions.
Pop Quiz Question: Direction of water flow?
Soil color as a diagnostic tool
Color reflects the parent material, the soil formation process, and
the hydraulic properties of the soil
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Soil Color
Coloring agents in the soilEffect/expression ofOrganic matterdarkens the soilIron (Fe):primary coloring agent in the subsoilorange brown colors associated with well drained soils are the result of Fe oxide stains coating individual particles.Manganese (Mn) is common in some soilsvery dark black or purplish black colorMatrix colorthe dominant color in the soilMottlingspots or blotches of color in the soil that differ from the matrix colorRedoximorphic featuresmottles that relate to the aeration, drainage, and alterations between aerobic and anaerobic of the soilRedoximorphic features
mottles that relate to the aeration and drainage status of the soil, and alterations between aerobic and anaerobic conditions of the soil
XTRA SLIDES
A
B
C
D
Deal or No Deal!
As a generalization soils of fine, very uniform texture and very limited
particle size distribution often have internal drainage limitations.
Alisol poorly drained clay loam
soil due to dense sub-surface
horizon rich in clay and
aluminum
Poorly drained silty clay
loam derived from alluvial
deposits on a modern-day
flood plain
Deep, poorly drained fine
sandy loam formed in
sandy marine deposits,
flood-plains and depressions.
Shallow water table
Moderately well drained, slow
permeability, deep to water
table. Smectite clay; high
shrink-swell properties
Soil colors associated with soil attributes.
Soil color Soil attributes Environmental conditions Brown to black (surface horizon) accumulation of organic matter (OM), humus low temperature, high annual precipitation amounts, soils high in soil moisture, and/or litter from coniferous trees favor an accumulation of OM Black (subsurface horizon) Accumulation of manganeseParent material (e.g. basalt) - Bright-light- nearly whiteElluvial horizon (E horizon) In environments where precipitation > evapotranspiration there is leaching of sequioxides, carbonates, and silicate clays. The elluviated horizon consists mainly of silicaBrown to black (surface horizon); surface well-drained, good aeration. Darker vertical soil deposits are remnants of burrowing animals.
The technical term is krotovina (crotovina): an animal burrow
that has been filled with organic or mineral material from another
soil horizon.
Reddish brown subsoil, suggesting good drainage, aeration. Note the buried A horizon, with additional subsoil material above suggesting colluvial deposition or some form of mass action in recent past. Zone of elluviation below the buried A horizon
Bright-light; eluvial zone
below the relatively
shallow organic horizon
near surface; the light-
colored soils, the abundance
of red and yellow suggest
a well-drained soil. Consider-
ing that elluviation has also
occurred, one would conclude
that this would be a suitable
site good internal drainage,
appears to have good water
holding capacity.
Redox reduction-oxidation status
Reduction oxygen is depleted from the soil, the soil may be anaerobic, iron and manganese chemistry change, resulting in color changes.Mottles/GleyingOxidation oxygen is present in the soil, the soil is aerobic, leaching is likely occurring, light color of soil.An explanation of the Munsell color wheel and Munsell color charts
Hue: It is the dominant spectral color, i.e., whether the hue is pure color such as yellow, red, green, or a mixture of pure colors.
Value: It describes the degree of lightness or brightness of the hue reflected in the property of the gray color that is being added to the hue.
Chroma: It is the amount of a particular hue added to a gray or the relative purity of the hue.
Standardizing Color the Munsell Color Chart
Munsell Color System Hue refers to the dominant wavelength of light (color) (red, yellow, green, etc.).Value refers to the lightness and darkness of a color in relation to a neutral gray scale.Chroma is the relative purity or strength of the Hue.NotationHue = 5YR
Value = 2.5 8
Chroma = 1-8
So, for example: a soil horizon with a Munsell color description of 5YR 5/4 =
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