GUELPH, ONTARIO - Agriculture and Agri-Food Canada

In many of the Grey-Brown Podzolic soils of Ontario there is a tendency
for a secondary profile to develop in the A horizons of the Grey-Brown Podzolic
soils. Generally this secondary development is evidenced by the establishment
of a definite leaf mat or A0 horizon, a thinning out of the dark coloured ‘41 horizon
and the development of a distinct brownish colour in the upper part of the
AZ horizon, This secondary profile in the upper part of the soil resembles the
Brown Podzolic soils in its morphological characteristics. However in some of
the coarser textured sandy soils a distinct light grey A:! horizon, similar to those
found in Podzol soils occurs below the thin A1 or A0 horizon. These secondary
profiles can best be observed under virgin conditions as the distinguished
features are readily destroyed on cultivation.
Closely associated with the Grey-Brown Podzolic soils are areas of Brown
Forest soils in which the leaching has not been very marked. These soils are
found in the northern part of the County. The well drained Brown Forest
soils in the area have a thin organic mat (A0 horizon) on the surface consisting
of leaf litter and semi-decomposed organic matter. The A1 horizon is usually
3 to 4 inches thick dark grey in colour, friable and of granular structure. It is
underlain by a brown B horizon which gradually grades into the pale brown
parent material. The reaction of the A horizon is approximately neutral while
the B horizon is slightly alkaline. In many instances the Brown Forest profiles
in Bruce County show indications of weak Grey-Brown Podzolic development.
In such soils there is a slight indication of the development of a brownish grey
AZ horizon under t!he A1 and there is a noticeable increase in the clay content
of the Bz horizon which is not characteristic of modal Brown Forest soils. Since
it is evident that certain Grey-Brown Podzolic characteristics are present in
the Brown Forest soils it would appear that the Brown Forest soils of Bruce
County are best correlated as Brown Forest-Grey-Brown Podzolic Intergrades.
A generalized profile description of a Brown Forest Soil follows:
A0 - Accumulated layer of partially decomposed litter
from deciduous trees.
A1 - Dark grey to dark greyish brown mineralized
layer.
B - Dark yellowish brown layer.
C- Light yellowish brown, calcareous, parent material.
A large proportion of the soils in the surveyed area have developed under
poorly drained conditions. The poorly drained soils of Bruce County are representative
of the following Great Soil Groups: Dark Grey Gleisolic soils, Bog
soils and Alluvial (young) soils.
The Dark Grey Gleisolic soils have a dark, friable, granular surface layer,
generally 4 to 6 inches thick which is underlain by a mottled brownish grey
subsoil that gradually grades into the parent material. In comparison to the
well drained soils that have uniformly brownish or yellowish brown subsoils
the poorly drained soils have rusty specks and streaks and bluish grey colours in
the subsoil. The discoloration or mottling of the subsoil is one of the distinguishing
features of poorly drained soils. The Dark Grey Gleisolic soils generally
do not have a marked leached layer or layer of accumulation. The following
is a generalized description of a Dark Grey Gleisolic soil:
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