1)The Five Soil Forming Factors: CLORPT

1)The Five Soil Forming Factors: CLORPT

Soil Study Sheet

1)The five soil forming factors: CLORPT

  1. CL=Climate
  2. O=Organisms
  3. R=Relief
  4. P=Parent Material
  5. T=Time

2)General Processes of Soil Formation

  1. Additions: New material is added to the soil (i.e. organic matter during autumn leaf fall)
  2. Losses: Material is leached or gasses out of the soil (i.e. nitrate leaches into groundwater. Ammonia volatilizes back into atmosphere)
  3. Transformations: Material is weathered physically and chemically into different material (i.e. quartz gravels break down into coarse sand)
  4. Translocations: Material is moved around in the soil profile (i.e. percolating water moves clay from top layers of soil into the B horizon)

3)Important Physical Characteristics of Soil

  1. Texture: The percentage of sand, silt and clay. Determines the “feel” of the soil
  2. Structure: How the soil solids are arranged/clumped together. Determines density, porosity, rate of water/oxygen entry into soil.
  3. Color: Can be used to determine depth to the water table, amount of organic matter in soil. Learn to use Munsell soil color book to accurately describe soil color.

4)The Soil Horizons

O – organic litter layer (leaves, grasses, twigs, etc)
A – “top soil;” the first below ground layer; humus rich
E – leached layer; the E stands for “exit” of iron and humus. Often white or grey
B –the clay layer. Generally sticky from clay and colorful – reds, yellows, oranges from iron oxides
C – transition from highly weather A,E,B to barely weathered parent material below. Generally less sticky, more gravelly than B
R – ROCK!

5)The 5 physiographic Provinces – from west to east

  1. Appalachian Plateau: Far southwest coal country
  2. Ridge and Valley: moutnains west of Shenandoah Valley
  3. Blue Ridge: the highest mountains, but very narrow province
  4. Piedmont: rolling landscape, largest province
  5. Coastal Plain: flat and wet, the fall line to the coast

6)The meaning of soil colors

  1. Grey redox mottles indicate saturation
  2. Reds, yellows and oranges generally indicate oxygen-rich, dry conditions
  3. Black and dark browns, especially in the top soil, indicate organic matter accumulation.

7)The drainage classes of soil

  1. Poorly drained – redox (grey splotches) within 10 inches of surface
  2. Somewhat poorly drained – redox in 10-18inches of surface
  3. Moderately Well Drained – redox in 18-36 inches of surface
  4. Well Drained – no redox within 36 inches of surface
  5. Somewhat excessively drained – no redox visible, soil is very sandy/coarse

8)Important Landscape Positions

  1. Ridge Top – top of the hill, king of the mountain!
  2. Shoulder slope – the steep land sloping off the ridge top
  3. Side slope – just below the shoulder slope
  4. Toe Slope – the bottom of the hill as it begins to flatten into the valley
  5. Flood plain – flat valley surrounding a river or stream, inundated during floods

9)Types of Erosion

  1. Raindrop/rainsplash erosion: rain drops on bare soil disperses and mobilizes soil
  2. Sheet: surface runoff strips off a fairly even “sheet” of soil from the surface
  3. Rill: When surface flows become concentrated, they start eroding out shallow trenches, or “rills,” in the soil surface
  4. Gully: Basically, rill erosion maximized. Concentrated runoff erodes out large trenches in the soil. Often can’t drive a vehicle over a gully.
  5. Stream bank: Erosion within a stream when the stream banks are eroded out wider due to large and fast volumes of water. Very common in urban areas or other areas where soil vegetation is lost.

10)Soil Parent Materials

  1. Eolian: Material deposited by wind
  2. Alluvium: Material deposited by water
  3. Colluvium: Material deposited by gravity (i.e. rockslides, landslides)
  4. Residuum: Material that weathers in place (i.e. soil forms from the weathering of the bedrock directly below it)

11)The Essential Macro and Micronutrients

a.Macronutrients: Nitrogen, Phosphorous, Potassium, Calcium, Magnesium, Sulfur

b. Micronutrients: Copper, Iron, Chloride, Boron, Manganese, Molybdenum, Zinc
-Some sources will also say Selenium and Chlorine

12)Soil Pollution Sources (and water too!)

  1. Point Source: You can “point” to it. A single, concentrated source of pollution, such as a sewage treatment plant, industrial facility, or power plant.
  2. Non-point source: You can’t “point” to it. Pollution that comes from many, diffuse small sources. Often, the specific sources may be a mystery. Examples: urban runoff, agricultural runoff.

13)Soil Surveys

  1. Where to find soils information for most areas in the United States: The Web Soil Survey
    Try it out and practice looking up soil maps, interpretations and suitabilities.

14)Land Capability Classes: Part of the Soil Survey

  1. Class 1: soils have few limitations that restrict their use
  2. Class 2: soils have moderate limitations that reduce the choice of plants or that require moderate conservation practices
  3. Class 3: soils have severe limitations that reduce the choice of plants or that require special conservation practices, or both
  4. Class 4:soils have very severe limitations that reduce the choice of plants or that require very careful management, or both.
  5. Class 5:soils are subject to little or no erosion but have other limitations, impractical to remove, that restrict their use mainly to pasture, rangeland, forestland, or wildlife habitat.
  6. Class 6:soils have severe limitations that make them generally unsuitable for cultivation and that restrict their use mainly to pasture, rangeland, forestland, or wildlife habitat.
  7. Class 7:soils have very severe limitations that make them unsuitable for cultivation and that restrict their use mainly to grazing, forestland, or wildlife habitat.
  8. Class 8:soils and miscellaneous areas have limitations that preclude commercial plant production and that restrict their use to recreational uses or wildlife habitat

Capability subclasses are soil subgroups within one capability class. They are designated by adding a small letter, "e," "w," "s," or "c," to the class numeral, for example, 2e. The letter "e" shows that the main hazard is the risk of erosion unless close-growing plant cover is maintained.
Subclass e =erosional problems
Subclass w = excess water problems/drainage issues.
Subclass s=shallow to bedrock, stony
Subclass c=climate problems (ie: too cold or dry)

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