What is the Agriculture Capability Rating System?

Where do I find Agriculture Capability Ratings?

 

The Agriculture Capability Rating System is a straightforward and understandable method designed to enable consistent and objective assessment of land based on inherent limitations for crop production. Agriculture Capability ratings can be used to inventory land assets, help determine realistic target yields and indirectly assess environmental risk (e.g. nitrate leaching).

The Agriculture Capability Rating System is a straightforward and understandable methodology designed to enable consistent, objective, field-specific assessment of:

• land resource assets and
• inherent limitations for crop production based on soil and landscape factors
   

The Agriculture Capability Rating System is similar to that of the Manitoba Agricultural Services Corporation (MASC), but only in general terms

• MASC uses a 10-class rating system for cultivated land based on soil productivity as determined by crop yields; each quarter section receives a single rating which is determined based on moving average cropping data, which can of course be influenced heavily by management
• Agriculture Capability ratings are based on inherent soil and landscape properties, not crop yield data, and limitations to crop production generally can not be altered dramatically by management (i.e. producers must work with “the hand that they’re dealt”); Agriculture Capability ratings can be used to:

• help determine, along with producer knowledge, realistic target yields and
• indirectly assess risk of nutrient loss (e.g. nitrate leaching) based on limitations to crop growth

Whenever soil survey maps are used, it must be recognized that Manitoba soil survey data, regardless of the source, are not all of the same scale

• Detailed soil survey data (scales of 1:20,000 to 1:50,000) should be used where they exist for a given area because the mapping is based on more field data and therefore provides a better (though not infallible) indication of soil types and variability present in a field
• Reconnaissance soil survey data (smaller than 1:50,000 scale, e.g. 1:126,720) should be used with caution only for areas which have not been mapped at a detailed level. Reconnaissance maps are based on less field data and therefore are less reliable in indicating soil types and variability, particularly at the individual field level
• Whether a map is in hard-copy or electronic form, it may not be evident that it is based on reconnaissance data – always check the source of the information for the scale of survey to determine the confidence level that is appropriate for a given map
• All soil survey information, regardless of scale, should be verified in the field whenever possible
• Table 1 illustrates differences between mapping scales and lists appropriate uses for each
• Consult the index for soil resource information in Manitoba to determine what soil survey information is available for a given location
• Soil Survey Reports can be obtained from:

Statutory Publications
200 Vaughan Street
Winnipeg, MB  R3C 1T5
Phone: 204-945-3101

Regardless of their scale, maps may not accurately represent current field conditions because they were created prior to management measures taken on a given field or because of inherent inaccuracies that are inevitable in any mapping exercise.

A rating for a given soil polygon or field should be based on actual conditions at the time of assessment, not just what is indicated on a map. As such, the producer/landowner is the best source of up-to-date information on the conditions in place on a particular field.

• Agriculture Capability ratings should be determined in consultation with the producer/landowner as much as possible to enable more accurate assignment of ratings or to confirm/refute the ratings provided on a reconnaissance map (unless the ratings are to be used for a Manure Management Plan – see How Do I Report Agriculture Capability Ratings in a Manure Management Plan?)

Agriculture Capability ratings, including class (1 to 7) and sub-class (e.g. M, T, W, etc.), are currently available from

• hard-copy publications

• detailed Manitoba soil survey reports (for areas that have been mapped at detail-level scales), which can provide both class and sub-class for each soil polygon – should be confirmed/refuted by the producer using Table 2 only if changes have been made through management, or
• Soils and Terrain Information Bulletins, which have been published for all Rural Municipalities by Agriculture and Agri-Food Canada, contain very generalized maps, which are based on either detailed or reconnaissance survey data depending on availability and are only suitable for obtaining very general ratings on a RM basis. These bulletins only provide class for each soil polygon – sub-class should be determined in consultation with the producer using Table 2
• electronic data sources

• the Agri-Maps Map Viewer website, which provides both the class and sub-class but should be confirmed/refuted by the producer/landowner using Table 2 when ratings are based on reconnaissance survey data
• the Manitoba Land Initiative (MLI) website, which can provide both class and sub-class but should be confirmed/refuted by the producer/landowner using Table 2 when ratings are based on reconnaissance survey data – to access the MLI, a GIS program called Arcview, or a free downloadable program called ArcExplorer2, is required
• digitized Soils and Terrain Information Bulletins on CD (identical to hard copies)

To determine Agriculture Capability ratings using a hard-copy soil survey report:

• Use the legal location to examine the soil map which contains soil series codes (e.g. PDA) which may include a phase (e.g. PDA/xcxx)
• Make a list of the soil series, including phases if identified, for each field, with their approximate relative proportions (e.g. 60% PDA, 40% DZW/xexx)
• Use this list to compile the corresponding Agriculture Capability ratings, contained in the Agriculture Capability table or list in the soil survey report, for each field
• Confirm/refute class and sub-class for each soil polygon in consultation with the producer/landowner using Table 2 only when changes have been made through management which may alter the rating

To determine Agriculture Capability ratings using a Soils and Terrain Information Bulletin:

• If a hard-copy is unavailable for a particular Rural Municipality, contact the Land Resource Unit, Agriculture and Agri-Food Canada, at 474-6118 for a digitized copy on CD
• Determine class using the Agriculture Capability map
• Confirm/refute class and determine sub-class in consultation with the producer/landowner using Table 2
• If assistance with interpretation is required for this source of Agriculture Capability ratings, contact the Land Resource Unit, Agriculture and Agri-Food Canada, at 474-6118.

To determine Agriculture Capability using the Agri-Maps Map Viewer

• Search by legal location
• Click on “Terrain and Soils” to access the “Agriculture Capability” database through the “Detail Soil Survey” directory if such information has been collected for the area of interest, otherwise through the “Reconnaissance Soil Survey” directory.

• Both the class and sub-class ratings are available, however, they should be confirmed/refuted by the producer/landowner using Table 2 for areas with only reconnaissance level information.
• Note that this website can be rather “temperamental” and so be patient when the “Retrieving Data” icon is showing (refrain from clicking too quickly or the program may crash).
• Also note that it tends to take longer to download information when accessing the internet using a dial-up connection.

To determine Agriculture Capability using the Manitoba Land Inventory (MLI), the GIS program Arcview, or a free downloadable program called ArcExplorer2, is required.

• This option provides both class and sub-class for each soil polygon regardless of the scale of soil survey information. Agriculture Capability ratings from this source should be confirmed/refuted by the producer/landowner if the map is based on reconnaissance data, using Table 2.
• If assistance with interpretation is required for reconnaissance data from this source, contact the Land Resource Unit, Agriculture and Agri-Food Canada, at 474-6118. *Note: Arcview is not widely available in MAFRI offices.
• Download ArcExplorer
• Register with MLI
• Bring up soil layer in MLI (Agricultural Interpretation Database (SoilAID))
• Download information for RM of interest from SoilAID
• Download Original Southern Quarter-section Grid
• Open ArcExplorer and use to view specific fields

Table 1  Number of inspections and proper uses for soil survey maps according to scale

Reconnaissance 1:125 000	Detailed 1:50 000	Detailed 1:20 000	Detailed 1:5000
Increasing level of information
~6 inspections/section	~ 16 inspections/section	~30 inspections/section	~128 inspections/section
General soil comparisons (subgroup/family/ association level) National scope Science projects Starting point for more detailed soils data collection	Field scale comparisons (series and phase level) Watershed management Land use assessment	Field scale comparisons (series and phase level) Precision agriculture Irrigation assessment Potato suitability Nutrient management Land use assessment	Field scale comparisons (series and phase level) Precision agriculture Irrigation assessment Potato suitability Nutrient management Land use assessment

 

Table 2  Matrix table for determining Agriculture Capability ratings, including class (severity of limitation for crop production) and sub-class (type of limitation for crop production) (modified from the Canada Land Inventory Soil Capability Classification of Agriculture (1965)).

 

For further information, contact your GO Representative.