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Soils
of the Pike Run Watershed
The
watershed is generally comprised of soils of the
Dormont-Culleoka association. Soils of this classification are
moderately to well drained, deep, gently sloping to very steep
on hilltops, ridges, benches and hillsides. This association
consists of hills with benches and ridges. The hills have long
slopes that commonly have slips. Small streams that form
drainage ways between hills drain most areas. "Slopes range from
3 to 50%. Dormont soils make up 40% of the association; 30% are
Culleoka; and 30% are comprised of minor soils," (USDA). "Soils
in areas of steep slopes are commonly shallow, poorly developed
and drained, with low fertility and high erosion potential.
Soils on less steep slopes and over unconsolidated sediments are
commonly deep, well-drained and fertile" (USDA).
"Dormont soils are dominantly on the hillsides and benches and
commonly have slips associated with them. The soils are deep and
moderately well drained,"(USDA). They have a seasonal high water
table with depths of 24-30 inches. They formed in a residuum of
watershed shale, siltstone, limestone, and colluvium.
"Culleoka soils are mostly on the ridges and hilltops but some
may be found on hillsides. The soils are moderately deep and
well drained,"(USDA). They formed in a residuum of the watershed
limestone, sandstone, siltstone, and shale.
The watershed consists of the following soil specifications in
order of abundance:
1. Dormont-Culleoka silt loams
This unit consists of moderate to steep slopes; deep,
well-drained soils on upland slopes are 100 to 800 feet long.
Dormont soils comprise 55% of the unit while Culleoka makes up
40% and 5% minor.
Typically, the surface and subsurface
of Dormont soils are dark brown silt loam and have a thickness
of 12 inches. The subsoil is 42 inches thick. The upper 15
inches is yellow-brown silt loams and silky clay loam. The lower
27 inches is mottled, yellowish-brown silty clay loam and
channery, silty clay loam. The substratum is mottle brown silty
clay to a depth of 78 inches.
The surface layer of the Culleoka soil is dark brown silt loam
about 11 inches thick. The subsoil is yellowish-brown and 14
inches thick. The upper 10 inches is light silty clay loam and
the lower 4 inches is shaly heavy silt loam. The substratum is
yellowish- brown very shaly silt loam about 3 inches thick.
Shale bedrock is at a depth of 28 inches.
These soils have slow permeability and high water capacity.
Runoff is rapid and the hazard of erosion is severe. Reaction in
unlined areas on the soil is mildly to strongly acidic to about
25 inches. The seasonal high water table is at a depth of 18 to
36 inches.
Most areas of these soils are used for pasture or are in
woodland or brushland. Slope and the hazard of erosion make
these soils unsuitable for cultivated crops and poorly suited
for pasture. The prevention of overgrazing is a primary concern.
These soils are well suited for trees, and the potential for
woodland is high. Slope limits the use of equipment and makes
mechanical impractical. Slope, the seasonal water table in the
Dormont soils, and bedrock depth in Culleoka is the main
limitations of community development. Low strength in the
Dormont soils is a hazard for roads and foundations.
2. Dormont soil loams
These soils are deep and moderately well drained. Slope are
100-500 feet long, areas are on uplands and range from 2 to 150
acres.
These soils are used for cultivated crops. Low slopes areas are
being the best suited. Contour strip-cropping and using minimum
tillage, grassed waterways, cover crops and hay in the crop
rotation help to reduce runoff and control erosion. Subsurface
drains are needed to drain wet spots in some areas. Growing
cover crops, returning crops residue to the soil, and using
grasses and legumes in the cropping system help to maintain the
organic matter in the soils.
These soils are well suited to pasture. The prevention of
overgrazing is a major concern. The use of proper sticking rates
to maintain key plant species; pasture rotation and periodic
nutrient replenishment are main management practices.
Restriction of usage during wet season helps to prevent
compaction of the surface layer.
These soils are suitable for trees and potential for woodland is
high. Machine planting is practical in larger areas but slope
limits use on steep soils. Constructing roads on the contour of
such areas helps to control erosion during timber harvests. The
seasonal high water table and slow permeability of the soils
limits community development, especially waste disposal. Low
soil strength limits roadways and foundations.
3.
Culleoka silt loams These soils are scarcely present
in the watershed. They are drained and deep. Slopes are up to
600 feet in length.
The surface layer is dark brown and 11 inches thick. The subsoil
is yellowish-brown and 14 inches thick. The upper 10 light silty
clay loam and the bottom 4 are a shaly heavy silt loam. There is
a 3-inch shaly silt substratum. The bedrock is at 28 inches.
These soils are suited to trees or pasture. They may also be
used for community development. Most areas, however, are used
for cultivated crops. (R. Vargo)
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