Exam 1 Flashcards
Soil Classifications Soil Forming Factors and Processes (43 cards)
Andisols (Order)
(and)
Parent Material- volcanic ash resulting minerals within the soil have poor crystal structures, and have an unusually high capacity to hold both water and nutrients
Light and fluffy
Very fertile
Ultisols (Order)
(ult) Acidic Infertile Highly weathered Low base saturation
Mollisols (Order)
(oll) Fertile soil Surface layer enriched in organic matter Enriched in base cations (Grasslands and prairies)
Oxisols (Order)
(ox) Defined by high Al/Fe content Highly weathered Low fertility Tropical/ equatorial region
Vertisols (Order)
(ert)
Shrink swell clay
Deep A horizon, no B horizon
High fertility (due to high clay content)
Gelisols (Order)
(el)
Frozen
Found in the Arctic and Antarctic, also at extremely high elevations
Permafrost influences land use through its effect on the downward movement of water and freeze-thaw activity (cryoturbation) such as frost heaves.
Permafrost can also restrict the rooting depth of plants.
Histosols (Order)
(ist)
Organic, wet
Mainly composed of organic matter
May be highly acidic
These soils form when organic matter, (leaves, mosses, or grasses), decomposes more slowly than it accumulates due to a decrease in microbial decay rates.
This most often occurs in extremely wet areas or underwater; thus, most of these soils are saturated year-round
Draining these soils can cause them to decompose rapidly and subside dramatically. They are also not stable for foundations or roadways
Spodisols (Order)
(od) Acidic Highly weathered (leaching environment) Cool, but not frozen Typically form in (Coniferous) forests Low fertility Low clay content
Entisols (Order)
(ent)
Newly formed (Little or no soil development other than the presence of an unidentifiable topsoil horizon)
Occur in areas of recently deposited sediments, often in places where deposition is faster than the rate of soil development
Inceptisols (Order)
(ept)
Slightly developed (young)
Exhibit a moderate degree of soil development and lack significant clay accumulation in the subsoil.
Aridisols (Order)
(id)
Very dry
The dry climate in which Aridisols occur restricts the soil weathering processes(rain).
Aridisols often contain accumulations of salt, gypsum, or carbonates, and are found in hot and cold deserts worldwide.
Alfisols (Order)
(alf)
Moderately weathered
Alfisols (from the soil science termPedalfer– aluminum and iron)
Similar to Ultisols but are less intensively weathered and less acidic
More fertile than Ultisols
Factors of soil formation (5)
- Parent Material
- Climate
- Biota
- Topography/Relief
- Time
Soil forming processes (4)
- Additions
- Losses
- Transformations
- Translocations
Clay formation process
Primary material -> Chemical weathering -> Secondary minerals
True/False
Sedimentary rocks form from cooling magma.
False. Igneous rocks are formed from cooling magma.
Sedimentary rocks are formed through compacting and cementing sediment formed by weathering and erosion.
Rock type formed from heat and pressure.
Metamorphic rocks
Basalt is…
Basalt is and extrusive igneous rock.
Epipedons (5)
Surface layers Mollic Umbric Ochric Melanic Histic
Mollic (Epipedon)
Mineral surface layer, high in organic matter with dark colour.
Fertile
More than 0.6% carbon
More than 25 cm thick
Umbric (Epipedon)
Mineral surface layer high in organic matter with dark colour. More than 0.6% carbon More than 25 cm thick Fertile (Less fertile than Mollic) Less than 50% base saturation
Ochric (Epipedon)
Pale in colour (Too pale or too thin or too low in organic matter to be Mollic or Umbric)
Melanic (Epipedon)
Dark, or black
More than 30 cm thick
Volcanic ash
Very fertile
Histic (Epipedon)
20-60 cm thick
Organic material
