Use of soil and Canada Land Inventory (CLI) information for agricultural land use planning in Ontario

Learn about soils mapping and the Canada Land Inventory (CLI) soil capability rating system and how it is used to support provincial planning policies for agricultural land.

The Canada Land Inventory (CLI) soil capability classification system for agriculture

The Planning Act requires that land use decisions made by municipal councils, the Ontario Land Tribunal, or other bodies must be consistent with the Provincial Policy Statement. The Provincial Policy Statement provides direction on the protection and designation of prime agricultural areas in municipal planning documents and establishes criteria to be considered when lands within a prime agricultural area are proposed for non-agricultural land uses. In its definitions of prime agricultural areas and prime agricultural land, the Provincial Policy Statement specifically refers to the Canada Land Inventory (CLI) system.

The CLI system is the recognized system in Ontario for classifying areas with mineral soils according to their inherent capability for growing common field crops. Common field crops include corn, wheat, soybeans, oats, barley, and perennial forage crops such as alfalfa and timothy. The system does not classify soils for horticultural or other specialty type crops.

Since CLI emphasizes the inherent capability of an area for field crops, the present land use, land management, land area or ownership are not considered. For example, a forested area may have a high CLI rating even though it is not cleared and developed for agricultural use.

CLI mapping and soil information is available for land use planning and other uses. Although other systems of classifying land have been developed, the CLI system continues to be the accepted system in Ontario for land use planning.

The CLI classification system for agriculture is an interpretive classification system. It was developed under the Agricultural Rehabilitation and Development Act (ARDA), a cooperative federal-provincial program aimed at providing a comprehensive national survey of land capability and use for various purposes.

The two main components of CLI are: 1) the capability class, and 2) the capability subclass. The capability class indicates the general capability of the soil for growing common field crops. Seven capability classes are defined and are explained in Table 1. The capability subclass indicates the primary type of limitation or hazard for growing common field crops. Thirteen subclasses are defined and are explained in Table 2.

Table 1: Capability classes - Class and Explanation

Classes 1, 2 and 3 - Capable of sustained use for growing common field crops; all or most crops can be grown.
Class 4 - Marginal for sustained use for common field crops; choice of crops that can be grown is limited.
Class 5 - Capable of use only for permanent pasture and hay.
Class 6 - Capable of use only for unimproved pasture.
Class 7 - No capability for agriculture

Table 2: Capability subclasses - Subclass and Explanation

C - Adverse climate
D - Undesirable soil structure and/or permeability
E - Damage from erosion
F - Low fertility
I - Flooding (Inundation) by rivers, streams, or lakes
M - Low moisture holding capacity (droughtiness)
P - Surface stoniness
R - Shallowness to bedrock
S - Two or more of subclasses D, F, M and N
T - Adverse topography
W - Excess wetness

Soil capability ratings

A soil capability rating consists of a capability class number followed by not more than two subclasses represented by their appropriate letters (e.g., 2W, 3FM, etc.). The severity of the limitations identified by the subclasses in the rating influences the class designation. Two subclasses may be shown in a capability rating when: 1) they represent limitations which are equal in severity, and both place the soil in the same capability class; or 2) they represent a combination of limitations which together place the soil in a certain class.

Both single and complexed capability ratings may be shown on capability maps. A single rating is shown in a map symbol when only one soil type occurs (e.g., 2T or 3W). When two soil types occur in an area shown on the map, a complexed capability rating is shown which includes separate ratings for each soil. The proportions of the area represented by each rating are indicated by a small numeral shown as a superscript after each rating. The numeric superscripts denote the proportion of the area out of a total of 10. For example, if the capability rating shown is 2T7 5R3, then 70% of the area is Class 2T and 30% is Class 5R.

Constraints in using the Canada Land Inventory

The classification system is applied only to areas with mineral soils. It cannot be used classify areas with organic soils. Organic soils are simply designated by the letter "O" on capability maps and have no CLI rating.

CLI maps published in Ontario present information at various levels of detail, depending on the scale of the soil survey maps they were derived from (Table 3). More information on soils mapping in Ontario can be found at Soils Ontario. Published provincial Soil Survey Reports can be found at Soil Surveys for Ontario. Small scale maps such as 1:250,000 cannot show areas smaller than 250 hectares in size. Larger scale maps such as 1:50,000 provide more detailed information, but cannot show areas which are less than 12 hectares in size (Table 4). Capability ratings for small areas may not be shown on those maps. Soil capability maps at a scale of 1:50,000 are best suited for municipal planning purposes, and allow for the identification of large continuous prime agricultural areas. While prime agricultural areas may have some areas of lower capability land and scattered non-agricultural uses, prime agricultural areas should not divide individual properties or exclude small, non-agricultural uses that are surrounded by agricultural uses. For more information on assumptions and the CLI System, see Classifying Prime and Marginal Agricultural Soils and Landscapes: Guidelines for Application of the Canada Land Inventory in Ontario.

Table 3: Historical soil maps and reports

County Year Survey Completed ON Report # Scale Last Updated Updated Scale
Blind River-Sault Ste Marie (now Algoma) 50 1:50,000 - -
Brant 1:25,000 - -
Bruce 1:63,360 1975 1:63,360
Dufferin 1:63,360 - -
Dundas 1:63,360 1999 1:50,000
1:63,360 - -

63 - v1
63 - v2

1:126,720 1:50,000
Essex 1:63,360 - -
Fort Frances - Rainy River 51 1:50,000 - -
Frontenac 1:63,360 - -
Glengarry 1:63,360 1999 1:50,000
Grenville 1:63,361 2001 1:50,000
Grey 1:63,360 1981 1:63,360
Haldimand - Norfolk 1:25,000 - -
Halton 1:63,360 - -
Hastings 1:63,360 - -
Huron 1:63,360 - -
Kenora - Dryden - Pointe Du Bois 52 1:50,000 - -
Kent (Chatham) 3 1:126,720 1996 1:50,000
Kent (Chatham) Special Report: Soil Maps of Kent County 1994 Special Report - - -
Lambton 1:63,360 - -
Lanark 1:63,360 2000 1:50,000
Leeds 1:63,360 2001 1:50,000
Lennox-Addington 1:63,360 - -
Manitoulin 1:63,360 - -
Middlesex 1:126,720 1:50,000
Niagara 1:25,000 - -
North Bay (now Nipissing) 54 1:50,000 - -
Northumberland 1:42,000 - -
Ottawa - Carleton (Excl. Urban) - - 1:50,000
Ottawa - Urban Fringe 1:25,000 1999 1:50,000
Oxford 1:63,360 1:50,000
Parry Sound 1:126,720 - -
Peel 1:63,360 - -
Perth 1:63,360 1975 1:63,360
Peterborough 1:63,360 - -
Prescott & Russell 1:63,360 1998 1:50,000
Prince Edward 1:63,360 - -
Renfrew 1:63,361 1990 1:50,000
Simcoe 1:63,360 - -
Stormont 1:63,360 1999 1:50,000
Sudbury 49 1:50,000 - -
Thunder Bay 48 1:50,000 - -
Victoria (now Kawartha Lakes) 1:63,360 - -
Waterloo 1:20,000 1996 1:50,000
Wellington 1:63,360 - -
Wentworth (Hamilton) 1:63,360 - -
York 1:63,360 - -

Table 4: Scale relationships and mapping objectives

Map Scale
Field Distances Represented by Map Lines
Minimum Area identifiable on map Mapping Objectives
  Metres Feet Hectares Acres
1:250000 250 812 250 620 Information for general purposes, broad provincial areas
1:250000 125 400 62.5 150 Information for large sub-provincial areas
1:50000 50 160 10 25 Information for municipal planning or watersheds
1:25000 25 80 2.5 6 Information for groups of farms or sub-watersheds

Specialty crop ratings

"Specialty crops" refer to fruit, vegetable and other crops grown commercially in Ontario which cannot be grouped with the "common field crops" (e.g., corn). The Provincial Policy Statement defines "specialty crop areas". While the CLI does not provide a soils capability rating for specialty crop production, the following publications and guidelines are useful for evaluating land and soil quality for specialty crops:

  1. 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.
  2. 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).
  3. 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.
  4. 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 fewer types of specialty crops but may still be well suited for some crops.

Examples of when the use of soil and CLI information may be required:

Preparing a new official plan, or updating an existing official plan, that identifies prime agricultural areas

Municipalities with an official plan are required by the Planning Act to review their official plan at least every five years to, among other things, ensure it is consistent with the Provincial Policy Statement, conforms with applicable provincial plans, and has regard for matters of provincial interests. During this process, municipalities should ensure the policies of their official plan reflect changing local needs and priorities. Resource areas of provincial interest such as prime agricultural areas, natural heritage resources and aggregate resources should be identified upfront so they can be considered when other planning issues are dealt with (e.g., the need to expand settlement areas).

The Provincial Policy Statement defines prime agricultural areas as areas where prime agricultural land predominates (i.e., specialty crop areas and areas with CLI Classes 1 to 3 land and associated Classes 4 to 7 land). The Provincial Policy Statement requires planning authorities to designate prime agricultural areas including specialty crop areas. Specialty crop areas receive the highest priority for protection of all prime agricultural areas. There are two approaches for identifying prime agricultural areas beyond specialty crop areas: Agricultural Land Evaluation System (ALES), and Land Evaluation and Area Review (LEAR) process. Both methods rely heavily on CLI mapping. More information on these methodologies is available from OMAFRA's Rural Planners.

Seeking an official plan amendment for a non-agricultural use

The Provincial Policy Statement states that planning authorities may only exclude land from prime agricultural areas for new or expanding settlement areas in accordance with other criteria established in policy. Conversion of prime agricultural area to settlement area may only be considered at the time of comprehensive official plan review, subject to conditions. Within the Greater Golden Horseshoe, an Agricultural Impact Assessment is required for settlement area boundary expansions. This may include analyzing CLI mapping.

The Provincial Policy Statement states that non-agricultural uses, specifically mineral aggregate extraction and limited non-residential uses may only be permitted in prime agricultural areas if certain conditions can be met. For instance, need must be demonstrated, and alternative locations evaluated outside of identified prime agricultural areas; where this is not possible, alternative sites should be identified on lower priority lands within the prime agricultural area. Lower priority agricultural lands are determined based on CLI and factors such as current land use, amount of capital investment into agricultural infrastructure, amount of land under active cultivation, degree of fragmentation to the surrounding agricultural land base, and proximity to adjacent urban and rural settlement areas. For the purpose of considering alternative sites, the scale of existing CLI mapping is appropriate.

Undertaking an Environmental Assessment (EA)

The Environmental Assessment Act requires the evaluation of impacts associated with proposed public sector and some large private sector undertakings on the environment (e.g., landfills, roads). The Environmental Assessment Act broadly defines "environment" as including the natural, social, economic, cultural, and built environments. Proponents must identify and evaluate alternatives, analyze effects, and identify impact mitigation. Consultation with the public, Aboriginal communities and government agencies is mandatory and must also be documented.

The potential impact of a proposed undertaking on prime agricultural areas and how impacts will be managed must be considered during the environmental assessment process. Within the Greater Golden Horseshoe, an Agricultural Impact Assessment or equivalent analysis is required for infrastructure projects which may include analyzing CLI mapping.

Further information on Ontario's environmental assessment process can be found on the Ministry of the Environment's website.

Applying for approval to operate a pit or quarry under the Planning Act and/or the Aggregate Resources Act

As CLI is the primary basis for determining capability for agriculture in Ontario, proponents and approval authorities for pit and quarry applications need to consider CLI information to be consistent with provincial policies that address the protection of prime agricultural areas) and rehabilitation requirements in prime agricultural areas on prime agricultural land. CLI classification is also considered when applying for a license under the Aggregate Resources Act. Further information on the process for pit and quarry applications can be found on the Ministry of Natural Resources' website. An Agricultural Impact Assessment is required for proposed mineral aggregate applications within the Greater Golden Horseshoe.


Classifying Prime and Marginal Agricultural Soils and Landscapes: Guidelines for Application of the Canada Land Inventory in Ontario

Agricultural Impact Assessment

Prime Agricultural Areas

Provincial Policy Statement

Land owners, land use planners, agricultural consultants and engineers, municipal governments and academics can go the Agricultural Information Atlas website to get agricultural information and create maps.

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