A Natural Resource Management Guide for the County of Morris A ...

The Ecosystem
Soil is an integral component in the local and regional ecosystems. Linked to water, flora, fauna, and humans,
it is the medium in which a host of plants and animals engage in symbiotic relationships. While appearing
stagnant, soil and its precursors are actually dynamic. Lichens, plant roots, and freezing water break parent
material apart into increasingly smaller units. Fungi and bacteria decompose organic matter, releasing
nutrients, and developing soil structure. Animals such as mice, moles, millipedes, wood lice, ants,
earthworms, termites, and centipedes migrate through soil, mixing up and aerating the various layers. Plant
roots enable soil aeration as well as provide nutrition via decomposition.
Soil Composition
Chemical, physical, and biological processes have resulted in vertical aggregations known as soil profiles.
The soil profile, as depicted on page 3-1, has been broken down into the following horizons:
topsoil or A horizon:
È
subsoil or B horizon:
È
parent material or C horizon:
È
R layer: È
layer of intense weathering; rich in organic matter
reaching a depth of 25 - 36 “; experiences some weathering;
receives partially chemically altered materials from A horizon
does not undergo much change
bedrock
Soil Components
The reasons soil does what it does are explained by its components, their properties, and the way that these
parts work together. The three major components of soil are sand, clay, and silt. They form multiple
combinations, e.g., gravelly loam, sandy loam, silty clay, etc. Combined in varying proportions, these
ingredients are responsible for soils' specific characteristics and properties, e.g., texture and erodibility.
“Water moves detached clay particles more readily than particles of silt or sand, but clay particle bonds are
generally stronger than those of silt and sand, so soils with a high content of clay may be quite resistant to
erosion.” 1
Soil Properties and Characteristics
There are many properties and characteristics pertinent to the construction and longevity of roads,
transportation facilities, infrastructure, foundations for buildings, irrigation systems, and septic systems. It
is clear from the listing how interrelated so many of the functions are. Examples of properties include: grain
size, color, steepness of slope, depth to bedrock, stoniness, organic matter content, erodibility, likelihood of
compaction, structure (influencing movement of water), texture (affecting soil porosity and permeability to
air and water), degree of wetness, permeability, susceptibility to flooding, seasonal high water table, clay
content (affecting water and ion absorption capacity, soil structure and permeability to air and water) and
shrink-swell potential. Appendix B provides a generalized representation of soil suitability for specific land
uses.
1 U.S. Department of Agriculture. Soil Conservation Service. Soil Erosion By Water,
Agriculture Information Bulletin 513, Aug. 1987.
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Soils