Soil Report - Agriculture et Agroalimentaire Canada

Soil Mapping
First, a legend was developed by compiling information
from existing resource publications such as geological
reports, conservation area reports, old soil maps, etc ., and
combining this with preliminary field observations .
Next, with the aid ofa stereoscope, tentative soil boundaries
were drawn on the most recent aerial photographs (scale
1:15 840) . With the legend as a guide, these soil boundaries
and the soils were checked in the field .
Field checking of the soils was done along all public
roads, where the soil was periodically examined, especially
where stereoscopic investigations had indicated major changes .
Soils were checked in fields, woodlots, and undisturbed
road allowances . Most sites were close to roads, but
occasionally it was necessary to traverse some distance into
concessions to verify soil boundaries .
Soil probes and Dutch augers were the tools most commonly
used to investigate soils . Soils were usually checked and
described to a depth of 1 m. Shovels were used occasionally
to dig pits and scrape down exposures along roads, ditches
and streams. Soil samples were periodically collected for
laboratory analyses, to verify or supplement field observations .
Between 5 and 10% of all sites were sampled for this
purpose .
The next operation was to compile the field and laboratory
information in the office onto 1 :25 000 scale topographic
base maps . Maps compiled in this way were published the
year following the field mapping as preliminary soil maps .
The last step was to prepare the final maps . This was done
by changing the map unit designations on the preliminary
maps to the final unique symbols, and by making any
necessary boundary changes . These final maps were prepared
for publication and entered into a computerized data file, by
the Cartography Section of the Land Resource Research
Institute, Agriculture Canada, Ottawa.
Survey Intensity and Map Reliability
The survey intensity level provides an idea of the precision
with which the soil survey was done . Survey intensity level l
indicates the precision of detailed, large scale surveys, e.g .
1 :10 000 ; survey intensity level 5 indicates the precision of
small scale surveys, e.g . 1 :250 000 (20) . The survey intensity
level ofthe Haldimand-Norfolk soil survey is at an intermediate
level, between levels 2 and 3 .
In this survey there was at least one soil inspection in most
map delineations ; boundaries of delineations were checked
at intervals in the field but mainly extrapolated from air
photos. The numberof inspections per cmz on the Haldimand-
Norfolk soil maps was about 0.2 or about one inspection per
29 ha (72 ac) .
Soil inspections were done by examinations of vertical
soil sections by probe, auger or shovel . Average depth of
examination was to about 1 m. Soils were occasionally
examined to the 1 to 2 m depth, usually at sites of deep
roadcuts or bank cuts .
Considering the survey intensity level and scale of the
Haldimand-Norfolk soil maps, the most appropriate uses for
these maps are for planning purposes of land areas such as
townships, small conservation areas, large urban subdivisions,
HOW THE SOILS WERE
MAPPED AND CLASSIFIED
25
or large farms . The suitability of the maps for uses of smaller
areas such as small farms, small subdivisions, building sites,
etc ., is less appropriate, because the average area covered
by map delineations of the Haldimand-Norfolk soil maps, is
about 33 ha (83 ac) .
Soil Classification
Soils of the Haldimand-Norfolk Region have developed in
soil parent materials ranging in texture from heavy clays to
coarse gravels . Most soil differences are related to these
textural differences . Variations in drainage also cause
differences between soils developed on the same soil parent
materials . Other soil forming factors, such as topography,
time, climate and vegetation, have also contributed to soil
differences .
Most of the soil parent materials in the Haldimand-
Norfolk Region are highly calcareous and alkaline . However,
the soils developed on such materials are less calcareous
because of the leaching action of water on soil bases,
especially calcium. This leaching action, along with associated
soil weathering, causes the development of soil horizons
near the soil surface . These horizons differ from each other
in properties such as texture, color, thickness, structure and
consistence .
- Ap horizon (very dark grayish brown)
- Bm horizon (brownish-yellow)
- Ae horizon (pale brown)
- Bt horizon (dark brown)
- Ck horizon (yellowish brown)
Figure 22 . Diagrammatic soil profile of a typical welldrained
soil in the Haldimand-Norfolk Region