Soil Report - Agriculture et Agroalimentaire Canada

B. AGRICULTURAL SUITABILITY
CLASSIFICATION FOR SPECIALCROPS
The CLI classification system of land capability for
agriculture is designed for common field crops, such as
forages, small grains and corn, but not for other less
commonly grown field and horticultural crops, henceforth
referred to as "special crops" .
Since a large portion of the Haldimand-Norfolk Region is
used for growing special crops, a suitability ratings system
was devised for the soils of the region, and for a number of
the most important special crops .
The ratings are based on information obtained from field
observations, agricultural extension personnel, and research
of relevant literature . Soil ratings for tobacco were prepared
with the assistance of J . Elliot, N. Sheidow and M. Watson
from the Delhi Research Station . Mr. Russ Chard, horticulture
extension specialist at the Simcoe Horticultural Station,
provided much of the information used for rating horticultural
crops . General guidelines on soil and land requirements
for many special crops were obtained from a literature
search. The publication, Climate and Soil Requirementsfor
Economically Important Crops in Canada, (26), was especially
helpful. The concept of lumping special crops into crop
groups (Table 11) was adapted from work done by D.
Cressman andM. Hoffman for Ontario Hydro (27) .
(1) Climatic Considerations
Because many special crops are less hardy than common
field crops, and often have specialized moisture requirements,
climatic factors are often as important as soil factors
in determining the suitability of areas for special crops .
Temperature, precipitation and growing season data for the
region are given in the climate section of this report . In
general the climate of the Haldimand-Norfolk Region is well
suited for a wide range of special field and horticultural
crops grown commercially in southern Ontario, mainly
because of its southerly location and proximity to Lake Erie .
(2) Soil Considerations
Table 12 indicates the suitability ratings of a number of
special crops for the soil map unit components ofthe region .
Ratings were done for the following special crops : apples,
apricots, asparagus, fava beans, green beans, lima beans,
soybeans, white beans, beets, cabbages, canola, carrots,
cauliflower, sour cherries, sweetcherries, sweet corn, cucumbers,
ginseng, hybrid and vinifera grapes, labrusca grapes,
lettuce, muskmelons, onions, peaches, peanuts, pears, peas,
peppers, plums, potatoes, pumpkins, radishes, raspberries,
rhubarb, squash, strawberries, tomatoes, turnips and
watermelons .
These crops were grouped into four main groups, mainly
on the basis of their response to soil conditions . Crop group
A is comprised of crops that seem to thrive best on sandy
and gravelly soils . Crop group B is composed of crops that
seem to be adapted to both sandy and loamy soils . Crops in
group C appear to be adapted to the broad spectrum of
sandy, loamy and clayey soils . Crops in these three groups
include field crops, vegetables and small fruits . Crop group
D is composed of tree fruits having potential commercial
significance in the region, and grapes .
Each crop group is divided into crop subgroups that are
composed of one or more crops . The crops in each subgroup
seem to respond similarly to most soils, and to differ significantly
from crops in other subgroups . The relation of crop
groups to crop subgroups, and the specific crops in each
subgroup, are shown in Table 11 .
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Table 11 . Distribution of special crops in crop group and
subgroup categories for the Haldimand-Norfolk
Region
Crop Sub-
Group group Special Crops
A 1 asparagus
2 peanuts
3 potatoes
4 tobacco
B 1 onions, beets, carrots
2 ginseng, muskmelon, watermelon
3 peppers, raspberries, rhubarb,
strawberries
C 1 fava beans, soybeans, white beans
2 green beans, peas, pumpkins, squash
3 cabbage, cauliflower, canola, sweet
corn, tomatoes, turnips
4 cucumber, lettuce, radish
D 1 apricots, sour cherries, sweet cherries,
peaches
2 pears, plums
3 hybrid and vinifera grapes, labrusca
grapes
4 apples
(3) How to Determine Special Crop Suitability Ratings
In Table 12, each crop subgroup is given a suitability
rating for most soil map unit components . Organic soils and
miscellaneous land units were not rated, and many alluvial
units could not be rated because of their various textures or
drainages . A six-class suitability rating system was used, with
ratings of good (G), fair to good (F-G), fair (F), poor to fair
(P-F), poor (P), and generally unsuitable (U) .
Average levels of management are assumed . Although
ratings are not improved in this system for superior
management, they are assumed to improve for some soils if
they are artificially drained or irrigated . In Table 12, those
soils that are most commonly drained or irrigated, and that
should improve by one or more suitability classes, if these
practices are put into effect, are indicated by +1, etc ., in the
appropriate management factor column . Flue-cured tobacco
is the only exception to this rule, because irrigation is
virtually universal on the crop . Thus, the ratings shown in
Table 12, for tobacco, assume that all tobacco soils are
irrigated . Most soils that are considered unsuitable for
certain crops will remain unsuitable even though artificial
drainage or irrigation is employed . The main exception to
this guideline are some poorly drained soils, denoted as U*,
that are assumed to be improved to a "poor" suitability class
with adequate artificial drainage .
Suitability ratingsdecrease with increasing slope, because
of erosion and topography limitations . The rate of decrease
varies, depending mainly on land slope, soiltexture and crop
type . The influence of these various factors on erosion is
discussed in "Soil erosion interpretations", in this report. In
Table 13 an attempt has been made, based on various
erosion factors, to provide guidelines on the rate of decrease
in suitability ratings as slope increases . To use this table, first
find the suitability rating of a special crop from Table 12,
and then, using Table 13, determine how the suitability
rating decreases as slope percent increases .