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Soils Online Study Guide
Introduction to Soils
This page is the online Soils Study Guide to assist students in preparing for
the NJ Envirothon. We hope that materials on this site will assist students in
their preparation for the 2003 Envirothon. Please continue to use the
training trunks and
other materials available through the Soil Conservation Districts.
The soil forming factors supply the initial material and conditions under
which a particular soil will form. The soil forming processes result from the
interactions of the soil forming factors. These processes influence and even
create a soil’s physical and chemical properties.
1. Functions of Soils
Soils are important because they perform many important functions, including:
- Sustaining biological activity, diversity, and productivity
- Regulating and partitioning water and solute flow
- Filtering, buffering, degrading, immobilizing and detoxifying organic
& inorganic materials
- Storing and cycling nutrients and other elements
- Providing support of socioeconomic structures
2. Variability of Soils
Soils vary from place to place due to differences in their Soil forming
factors, Soil forming processes, and/or Soil properties:
a. Soil forming factors (see From the Surface Down, section 2)
- Parent material
- Climate
- Organisms
- Landscape position
- Time
b. Soil forming processes (see From the Surface Down, section 3)
- Additions
- Losses
- Translocations
- Transformations
1. Soil physical properties
- horizonation
- soil color
- soil texture
- soil structure
- soil consistence
- bulk density
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2. Soil chemical properties
- Cation Exchange Capacity
- Soil Reaction (pH)
Reference:
NRCS Soil Quality Institute
website
Surficial geology and bedrock geology maps, and geologic information is
available from New Jersey Geological Survey website.
These documents require
Adobe Acrobat.
From The Surface Down (1.4 MB)
3. The Soil Environment
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“Phases” of Soil
In their natural setting, soils exist as a “three-phase” system comprised of
a:
- “solid phase” – the soil matrix; includes inorganic material with
various chemical and mineralogical properties, and organic material in
varying degrees of decomposition
- “liquid phase” – the soil solution; includes soil water and its
dissolved substances
- “gaseous phase” – the soil air; more variable in composition than the
air above the soil
An ideal soil contains:
- 50% solid matter, of which 45% is mineral soil material and 5% is
organic soil material
- 50% pore space, of which 25% is soil water and 25% is soil air
- Water Movement in Soils
- Effects of Saturation by Water on Soils
- Fragipans
For more information contact your local
Soil Conservation District Office or
Richard Belcher, NJ Envirothon Coordinator Phone: (609) 292-5540,
Fax: (609) 633-7229.
< Back to Soils Online Study Guide
Last Modified:
February 07, 2008
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