ecological characterization atlas of coastal alabama - Data Center

SOILS AND LANDFORMS
INTRODUCTION
This atlas topic deals with the natural phenomena of soils, landforms,
and related subjects, which includes regional surface landforms, soils, beach
erosion and accretion areas, faults, high-energy beaches, and active dunes .
This narrative supplements the atlas maps by explaining not only how and
where environmental conditions currently exist but also how they have
appeared or evolved in the past . The information is relevant to decisionmakers
charged with duties ranging from preservation and conservation to
responsible, economically feasible land and resource development .
REGIONAL SOILS AND LANDFORMS
The most detailed soil classification is the soil phase . A soil phase is
a subdivision of a soil series based on differences that affect management of
that subdivision . A soil series may be divided into phases on the basis of
differences in slope, thickness (depth), stoniness, or any other characteristic
that affects its usage . An example of a soil phase would be "Troup loamy
sand, 5% to 8% slopes ."
Groups of soils derived from similar parent material and similar in
vertical profile characteristics and arrangement are called soil series .
Soils within a series may have some variation in the texture of the surface
horizon (layer), but are similar to one another in color, structure,
reaction, chemical composition, and overall consistency .
A group of soil series that is found in the same geographical area and
generally occurs in a characteristic pattern is called a soil association .
For example, the Izagora-Bethera-Suffolk soil association (map unit 13) is
where Izagora soils are found on higher, flatter areas ; Bethera soils are
found in the depressions and drainage ways, and Suffolk soils are found on
the slopes connecting the two . These associations are usually defined and
delineated as a single map unit, and are the basic units dealt with in this
atlas . Although most of the areas in an association are composed of major
soil series, there are a number of other soil series within the association
which are less common ; these are called minor soils .
The soil association maps available in the soil surveys of Mobile
(Hickman and Owens 1980) and Baldwin (McBride and Burgess 1964) Counties are
at 1 :316,800 scale, (1 cm = 3 .2 km, 1 inch = 5 mi) . This information
was transferred to the 1 :100,000 (1 cm = 1 km, 1 inch = 1 .6 mi) scale
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