Agricultural Land Evaluation System (ALES) Methodology

Agricultural Land Evaluation System (ALES) and Land Evaluation and Area Review (LEAR) are two recognized methodologies for informing the designation of prime agricultural areas, if a study is needed. A study using these approaches may be conducted to help identify prime agricultural areas or the agricultural land base more broadly, for designation in official plans. In municipalities where the land outside settlement areas meets the definition of a prime agricultural area, a study may not be required in order to designate the area in an official plan.

This page provides a recommended ALES approach for identifying and designating prime agricultural areas. The ALES approach is best described as a 'table-top' exercise, where relevant information sources (e.g., soil capability, land use, etc.) are analyzed to determine if areas meet the characteristics of a prime agricultural area. In comparison, the LEAR approach relies on Geographic Information System (GIS) modelling to assist with the identification of prime agricultural areas.

Understanding the Characteristics of Prime Agricultural Areas

When evaluating whether lands should be included in a prime agricultural area, it is important to consider the Provincial Policy Statement's (PPS) definitions of prime agricultural land and prime agricultural area.

Prime agricultural land: means specialty crop areas and/or Canada Land Inventory Class 1, 2, and 3 lands, as amended from time to time, in this order of priority for protection.

Prime agricultural area: means areas where prime agricultural lands predominate. This includes areas of prime agricultural lands and associated Canada Land Inventory Class 4 through 7 lands, and additional areas where there is a local concentration of farms which exhibit characteristics of ongoing agriculture. Prime agricultural areas may be identified by the Ontario Ministry of Agriculture and Food using guidelines developed by the Province as amended from time to time. A prime agricultural area may also be identified through an alternative agricultural land evaluation system approved by the Province.

OMAFRA's prime agricultural area webpage explains that prime agricultural areas are not only areas where Canada Land Inventory (CLI) Classes 1 to 3 land predominates, but often also include associated CLI Classes 4 to 7 lands. It should be noted that organic soil is mapped in CLI but does not have a CLI rating. Even so, lands with organic soils should be carefully considered during an ALES exercise. Organic soils can be very productive for agriculture, particularly if improvements are undertaken (e.g., installation of tile drainage) or when used for crops such as certain vegetables that thrive in organic soil. The CLI agricultural capability mapping from Ontario GeoHub should be used as it provides the most current information. Additionally, prime agricultural areas include areas where there is a local concentration of farms which exhibit characteristics of ongoing agriculture. When assessing this portion of the definition, a variety of factors should be considered:

  • What is the actual land use? Is the land being used or have potential for agricultural purposes?
  • Have investments been made into crops (e.g., perennial plant stock such as trees or grapevines), or agricultural infrastructure (e.g., livestock facilities, other agricultural buildings, drainage systems, fencing)?
  • What are the lot size(s) within the study area? Is there a high degree of lot fragmentation?

In general, areas with a concentration of agricultural uses, productive soils, with a low degree of fragmentation, and investments into agricultural uses and associated infrastructure are characteristic of prime agricultural areas.

Recommended Area Threshold

To be consistent with the PPS, OMAFRA recommends that contiguous lands, generally 250-ha or larger, where prime agricultural area characteristics predominate, should be present to support a prime agricultural area designation. This threshold is not intended to prevent approval authorities from designating smaller areas with prime agricultural area characteristics. Conversely, areas that do not exhibit prime agricultural area characteristics are recommended to be contiguously 250-ha or larger in size in order to be excluded from the prime agricultural area. When assessing where/when characteristics predominate, a generally >50 per cent threshold is applied on a parcel-by-parcel basis.

Establishing Designation Boundaries

OMAFRA also recommends applying common conventions when delineating prime agricultural areas for designation. When determining the extent of prime agricultural areas, designations should be adjusted to an identifiable boundary such as a lot line, roadway, railway or water body. Where present and mapped, features such as infrastructure corridors (e.g., hydro corridors) can be used. Small pockets of non-agricultural uses may be present within a prime agricultural area and should not be excluded from the designation. Generally, prime agricultural areas should not divide individual parcels. However, in certain circumstances it may be appropriate to identify a designation boundary at a mid-concession point. This approach may be suitable for large lots (typically the original surveyed 40-ha lots) where the predominate characteristics drastically differ (prime vs. non-prime) from one end of the lot to the other.

Resources to Assist with the Evaluation

ALES analysis can be supported by data and tools accessible in OMAFRA's Agricultural Information Atlas (AgMaps). This public-facing GIS tool provides the capability to overlay relevant data layers to compare and evaluate the characteristics of the land. This tool can be used to assist with mapping work by providing access to CLI ratings, soil mapping, satellite imagery, parcel fabric, drainage information, etc.

Finalizing Maps

Before making final mapping decisions, it is strongly recommended that ALES' study results be checked directly on the ground to confirm the designation and its boundaries. This is particularly important for areas where current satellite imagery is not available. Site visits often reveal conditions that were not anticipated based on desktop information. This verification of facts is particularly important in areas experiencing agricultural expansion activities (such as tree-cutting or drainage improvements), which have opened or re-introduced lands for agricultural use. Consulting with local Agricultural Advisory Committees where they exist, or agricultural organizations about the history and current use of land may also be beneficial. To achieve continuity of prime agricultural area designations across neighbouring jurisdictions, consultation with adjacent jurisdictions is recommended.


For more information:
Toll Free: 1-877-424-1300
E-mail: ag.info.omafra@ontario.ca