The Soils of The Regional Municipality of Ottawa=Carleton

Recognized Recognized
Subgroups Series
M16 : Dominantly poorly Orthic Humic Dunrobin
drained soils in Gleysols (poor)
combination with OrthicSombric Mille Isle
significant areas of Brunisols (well)
well-drained soils Orthic Dystric Constance
found on undulating
topography dominatedby
broad depressional
areas . Slopes are
2% or less .
Brunisols (well) Bay
Taxonomic Components Excessive to well-drained soils of
the association have surface A horizons which are variable in
thickness . The Mille Isle series (Orthic Sombric Brunisol subgroup)
has a surface A horizon at least 10 cm thick, with very
dark grayish brown to black colors . The underlying subsoil
grades from strongbrown to dark yellowish brown inthe upper
B horizons, to brownish yellow in the parent material . Structure
at the surface is weak subangular blocky, and weak subangular
blocky or single grain in the subsoil. The Constance Bay
series (Orthic Dystric Brunisol subgroup) has a surfaceA horizon
which is less than 10 cm thick . Occasionally it has a thin
eluviated Aej horizon which is light reddish brown in color.
Across the landscape the Aej horizon is discontinuous . Colors
and structure ofthe surface and subsoil horizons are similar to
the Mille Isle series.
The imperfectly drained Herbert Corners series (Gleyed
Sombric Brunisol subgroup) has a surface A horizon at least 10
cm thick, and is the most common component associated with
imperfect drainage conditions . Occasionally the surface is less
than 10 cm thick, in which case the soils are classified at the
subgroup level as Gleyed Dystric Brunisols . Surface A horizons
of the Herbert Corners series are dark yellowish brown,
and subsoil B horizons are slightly lighter. Parent material
color is pale brown . Structure ofthe profile grades from single
grain or weak subangular blocky at the surface to single grain
in the parent material . Distinct to prominent strong brown
mottles are present inthe subsoil .
The poorly drained Dunrobin series (Orthic Humic Gleysol
subgroup) has a high water table for a major part of the
growing season. Surface A horizons are dark reddish brown to
black in color, while underlying B horizons are dark brown to
dark grayish brown . Parent material is most commonly grayish
brown in color, but may occasionally be grayer. Structure
throughout the profile is single grain .
Mapped Soil Combinations Mille Isle soils were usually
mapped individually. Therefore, repetitive or commonly
occurring map combinations with other soils do not occur. The
few combinations which do occur were necessary because of
scale limitations, or because the separation of individual soils
was not feasible .
General Land Use Woodland is the most common land use
associated with Mille Isle soils . Significant but less extensive
areas consist of abandoned farmland and scrubland . Agriculture
in general is not a significant land use, and if present it usually
consists of grazing land . In Osgoode Township, however,
some specialty agriculture in the form of sod farms and
orchards is found on Mille Isle soils .
Correlation to Ottawa Urban Fringe Mille Isle soils mapped
in the survey area are similar in most aspects to those in the
Ottawa Urban Fringe area . Some additional taxonomic components,
however, were identified in the survey area . Also, a
wider range in soil reaction occurs which is not significant for
interpretation purposes .
NEPEAN (N)
Location and Extent Soils of the Nepean association occur
only in the City of Kanata and some adjacent areas of West
Carleton Township. Approximately 1,500 ha of Nepean soils
were mapped .
Landform and Topography Nepean soils consist of a 10 to 50
cmthickveneer ofstony undifferentiated driftmaterial overlying
sandstone and quartzite bedrock . The topography is controlled
by the underlying bedrock, and is generally nearly level
to very gently sloping with slopes ranging from I to 5016 . Occasionallygently
sloping topography is present, with slopes ranging
from 6 to 9% . The underlying bedrock may belong to
either theNepean, March, orRockcliffe formations since each
is either entirely or partially composed of sandstone.
Landform characteristics of the Nepean association are
similar to those of the Farmington association except that Farmington
soils overly limestone and dolomite bedrock .
Soil Material Nepean soil materials are moderately coarse to
coarse textured and contain a considerable amount of angular
sandstone fragments . In places, some angular or rounded limestone
or dolomite fragments have been incorporated from
adjacent Farmington or Grenville soils, and there is also a
small percentage of rounded stones of Precambrian origin .
Although the thickness of Nepean materials ranges from 10 to
50cm, the majorityofmaterials are quite shallow andoften are
less than 30 cm thick . For this reason bedrock exposures are
common in most Nepean landscapes and may occupy as much
as25% ofthe areaof some map units .
The parent material ofNepean soils is noncalcareous and
acidic in reaction . These factors combined with the overall
shallowness ofthe material makes the differentiation of parent
material from weathered subsoil difficult . In many soils all of
the material overlying bedrock has been weathered and original
parent material is not present . Subsoil materials, therefore,
are commonly strong brown to yellowish brown in color and
slightly to very strongly acid in reaction . Loamy sand textures
are most prevalent, with sandy loam and sand textures also
occurring but less extensively. Surface textures are slightly
finer with sandy loam being the most common . Occasionally
silt loam and loam textures also are present at the surface.
Coarse fragments primarily consisting of flat angular pieces
of sandstone are present throughout the material, but usually
constitute less than 20% of the total volume. Some soils, however,
have a significantly higher proportion of coarse fragments
.
Stones greater than 15 cm in diameter are present on the
surface of most Nepean soils . The amount ofstones at the surface,
however, are quite variable . The majority of soils are
slightly to moderately stony, with less than 3% surface coverage
of stones . More severe surface stoniness, however, is common
on some soils with as much as 50% of the surface covered
by stones .
Materials of the Nepean association can be differentiated
from those of the Farmington association on the basis of a
number of physical and chemical characteristics . Nepean
materials generally have a larger proportion of sand and
coarser textures . They contain very few limestone or dolomite
coarse fragments, with the predominant type of coarse fragment
being sandstone . Subsoil materials tend to be lighter in
color, and they are acidic rather than neutral to mildly alkaline
in reaction. Nepean soils in general also have a thinner veneer
of drift material thanthat normally found in Farmington soils .
Bedrock exposures are therefore more common in Nepean
landscapes .