Guidelines for Detailed Soil Surveys for Agricultural Land Use Planning
Table of Contents
More detailed, property specific soil surveys are sometimes needed when a land use change (e.g., an official plan amendment) is being sought that would permanently remove the land from agriculture. The Planning Act establishes that decision makers such as municipalities and the Ontario Municipal Board must have regard for the Provincial Policy Statement of 1997. This statement provides direction on the protection of prime agricultural areas, and establishes criteria to be considered when prime agricultural lands are to be designated for non-agricultural land uses.
The following guidelines provide direction for land resource consultants and their clients undertaking detailed soil surveys for the assessment of agricultural crop capabilities and suitabilities. For these guidelines a "detailed" soil survey is one compiled at a working map scale of 1:10,000 or greater. These guidelines, or terms of reference, are a set of basic requirements to ensure that planners, landowners and consultants have the necessary detailed agricultural land resource information presented and reported in a standard form in order to make planning decisions or to advocate for changes to planning decisions.
The need for detailed soil information for some local decisions often arises from concerns with
- the accuracy of the published soil information mapping, classification, and agricultural interpretations.
- situations where the published information is too general for decisions about a specific area.
"Published soil information" refers to the county and municipal soil reports and maps, and also the Agricultural Capability maps. These map and report documents are all available from OMAFRA.
Soil Survey Components
- The soil survey should be done according to generally accepted
soil survey procedures and be based on an adequate density and
distribution of soil profile and landscape inspections. A general
guideline is one ground inspection per two square centimetres
on the final map (Soil Mapping System for Canada, Agriculture
Canada, 1981). At a scale of 1:10,000 this is one inspection per
two hectares. Inspection locations and data should be included
with the soil map and report.
The "Field Manual for Describing Soils in Ontario" (Ontario Centre for Soil Resource Evaluation, 1993) provides guidelines for classifying soils and the landscapes in which they occur.
- Soils of the subject area should be correlated with the soils classified in the published soil survey map and report for that county or municipality.
- Agricultural capability for common field crops (corn, soybeans, small grains, forages) should be interpreted using the document "Classifying Prime and Marginal Agricultural Soils and Landscapes: Guidelines for the Application of the Canada Land Inventory in Ontario". As explained in this document, land and soils which are classified as "prime agricultural land" (CLI classes 1 to 3) have necessary capital improvements in place or it is physically feasible for the landowner/manager/farmer to make the necessary improvements. If it is not feasible to make improvements that would enable mechanized row cropping, then the land may be considered as less than "prime" (CLI class 4 or 5). The question of "feasibility" often arises about land with wetness limitations for which more drainage improvement is required for productivity to be optimized. Each case must be considered individually. The Agricultural Drainage System Mapping (OMAF) for the subject area is a necessary reference to help argue and answer the question of drainage improvement feasibility.
- If the subject area lies within or adjacent to a larger area
of specialty crop production, then its soil suitability for specialty
crops needs to be evaluated. (Provincial Policy Statement, 1996).
"Specialty crops" refer to fruit, vegetable and other crops grown
commercially in Ontario and which cannot be grouped with the general
"common field crop" types listed above. A definition of "Specialty
crop land" is given in the Provincial Policy Statement. The following
publications and guidelines are useful for evaluating land and
soil quality for specialty crops:
- More recent soil survey reports (Brant, Elgin, Haldimand-Norfolk, Middlesex, and Niagara) include ratings of soil suitability for some specialty crops. The ratings published in these reports may also guide the interpretation of reasonably correlated soils in adjacent counties whose soil reports contain no such specialty crop interpretations.
- The publication "A Compilation of Soil, Water and Climatic Requirements for Selected Horticultural Crops in Southern Ontario" (Ontario Institute of Pedology Publication, 1989) outlines general landscape and moisture needs for more than 40 different tree fruit, small fruit and vegetable crops. It comprises many of the soil principles used to arrive at the soil suitability ratings given in soil survey publications cited in (a).
- Irrigation and/or artificial drainage are often necessary, depending on the site and crop. Climatic regime needs consideration. The longer the frost free period and the greater the heat units available, the greater the range and productivity of crops land tends to support.
- In general, soils which are interpreted to be "prime" (Class 1-3) for the common field crop types of corn, soybeans, small grains and forages will have viable suitability for a range of specialty crops. This is most true of sandy and loamy soils. Clayey soils are suitable for a lesser range of specialty crops but may still be well suited for some crops.
Provincial Policy Statement, 1997.
The Canadian System of Soil Classification; Agriculture and Agri-Food Canada, 1998
Field Manual for Describing Soils in Ontario; Ontario Centre for Soil Resource Evaluation, 1993.
Classifying Prime and Marginal Agricultural Soils and Landscapes: Guidelines for Application of the Canada Land Inventory in Ontario; Ontario Ministry of Agriculture and Food, 2004
A Soil Mapping System for Canada: Revised; Agriculture Canada, 1981
Agricultural Drainage Systems Mapping, OMAFRA, 1983
A Compilation of Soil, Water and Climatic Requirements for Selected Horticultural Crops in Southern Ontario, Ontario Institute of Pedology, 1993
In order to ensure that all of the components for the detailed soil survey are completed properly, an experienced pedologist should be retained for any survey work.
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