Agriculture

Interpretive Maps

The maps and charts in this section can help you determine suitable uses and management practices for land parcel. You can also learn more about how soil ratings are establishing using soil survey data.

Understanding soil interpretation

 

Suitability Ratings

 

Special Reports/Map Products

A generalized Soil Landscape Map provides an overview of major soils for all of Manitoba at a scale of 1:1 000 000. This Soil Landscape Map has been used to derive a series of maps depicting soil degradation by wind, water and salinization. Also, publications describing minor element content of surface soils, engineering equivalents of the soils and the soil component of the ecological framework have been based on the Soil Landscape Map.

Other Resources

Introduction

Soil interpretation refers to the behavior and response of soils to human activities. The information assembled in a soil survey can be used to predict or estimate the potentials and limitations of the soils’ behavior under different uses. As such, soil surveys can be used to plan the development of new lands or to evaluate the conversion of land to new uses.

Soil surveys also provide insight into the kind and intensity of land management that will be needed. An example of soil survey interpretation is the evaluation of a given landbase for manure application.

The type of soil and its associated characteristics determine the crops that can be grown, their yield potentials, the quantities of nutrients that are needed and the field practices that will be necessary to maintain optimum soil conditions for plant growth. As well, soil data on permeability (the rate at which water moves through a soil), depth to groundwater, flooding, slope gradient, soil texture and depth to bedrock can be useful in determining the risk of groundwater contamination due to leaching or surface water contamination due to runoff and erosion.

The following conceptual model depicts the information required to make on-farm land use and land management decisions that are objective, consistent and technically sound.

Detailed Soils Info (Baseline Data) Ex:. LOP/xcxx

+

Standardized Interpretive Criteria Ex: agriculture capability - 4M

=

Appropriate Land Use and Management Ex: most suitable for improved forage or pasture under dryland conditions

Capability versus Productivity versus Suitability

There are three rating systems used ; Agriculture CAPABILITY, Soil PRODUCTIVITY Index (MASC) and Irrigation SUITABILITY. Here are the differences:

Capability implies the ability to perform actions or to be affected by an action. It refers to features or qualities that can be used for a purpose (in this case agricultural production). The Agriculture Capability system ranks the ability of a soil to be used for the purpose of agricultural production.

Productivity refers to a measure of output from a process. The Soil Productivity Index developed by the Manitoba Agricultural Services Corporation (MASC) consider not only soil and landscape characteristics, but also crop yields as a measurable outcome.

Suitability implies something is appropriate to a purpose. In the case of Irrigation Suitability, the soil properties make the area suitable for irrigation and sustainable irrigated crop production.

Soil Productivity Index Ratings

The soil productivity rating system was developed and used by Manitoba Agricultural Services Corporation (MASC) to rank the inherent productivity potential of Manitoba’s soils for crop insurance purposes.

Soil productivity is dependent upon the interaction of certain soil factors with one another and with climate. Most of Manitoba’s agricultural land has been mapped and classified in soil survey reports. Soil survey information provides the basis for the soil productivity rating system.

Major soil types in the province (benchmark soils) were selected and the long term average wheat, oats and barley yields were obtained for each soil. The benchmark soils were then placed in one of ten classes (A – J) with the soils having the highest yields being classed as A and the lowest yielding soils being rated as J. The characteristics of all other soils mapped by the Soil Survey were then studied and compared to these benchmark soils and were placed in appropriate productivity classes.

Risk Areas are defined and used in the productivity rating as an area of common production risk. The criteria used for delineating risk areas were to place areas with similar soils and/or climate into a common group. In Manitoba each risk area can have up to ten soil classes (A to J). In the productivity rating a soil class in one risk area does not necessarily have the same productivity as the same soil class in another risk area.

In addition to the yield history and risk areas, the other key factors used for MASC purposes in establishing the productivity rating of a soil include the soil properties (texture, organic matter, topsoil depth, salinity, and stoniness), climate (length of growing season, frost hazards, heat units, precipitation totals and distribution as well as evaporation rates), sensitivity (flooding, drought, erosion), hydrology (internal drainage, surface runoff, proximity to bodies of water), and terrain (landforms, substrata).

MASC has given all agricultural land of Manitoba a soil productivity rating for coverage purposes. Annual probable yields or bushel coverages are calculated on 10 year moving averages. Generally, the soil productivity indexes reflect the average yields. As the soil productivity rating decreases the average yield also decreases. More details are available at the MASC Website.

How does Agriculture Capability compare to the Soil Productivity Index ratings?

Crop insurance coverage is based on a 10-category classification system for cultivated land based on soil productivity as determined by crop yields. The ratings are from A to J with A being the most productive and J the least. Each quarter section receives a single rating and the ratings are calculated based on moving average cropping data, temperature, precipitation and soil factors such as organic matter, sub-surface material, texture, drainage, depth of topsoil, topography, salinity and erosion. Ratings are modified to account for local risk factors such as frequency of drought, frost, flooding and other natural hazards. As a result, a quarter section with several soil polygons will have several agriculture capability ratings, but will always have one soil productivity index rating.

  Soil Agricultural Capability Soil Productivity Index (SPI)
Class or category 7 class rating - Class 1 to 7, 11 Agricultural Capability subclasses 10 – category ranking A to J
Goal Agricultural Capability was used to rate soil’s capability to sustain crops based on major limitations. MASC’s goal was to develop and use SPI rating to reflect crop productivity potential for crop insurance purposes.
Sources & features of data used Soil survey assigns Agricultural Capability ratings for polygons based on the field and laboratory information. Manitoba Soil Survey data provides the basis for SPI rating
Major soil types in MB were selected; long-term (>35 years) data including average yields of several main crops were collected for each soil by 3 organizations.
Implication for productivity Agricultural Capability does not rate the productivity of the soil. SPI system rates the productivity of a soil focusing on crop insurance use.
Agricultural capability is based on the Canada Land Inventory (CLI) Soil Capability Classification for Agriculture. The purpose of MASC developing SPI system was to make a custom soil classification / rating to be all things to all people, like crop insurance, land assessment, and farm credit.
Agricultural Capability is polygon-based. SPI was set up to specifically fit the needs of the above user groups. In another word, it is a little more targeted on specific purpose such as crop insurance.
Decisive aspect of system Identifying the levels of limitation factors, i.e., soil properties, landscape and climate effects. Determined by crop yields, i.e., yield-based, economic-output-indexed.
Relationship with multiple aspects of cropping and yield data Agricultural Capability is designated based the limiting conditions that may restrict agricultural use of a soil, such as wetness, stoniness, erosion, salinity, and inundation. SPI ratings are calculated based on moving average cropping data, temperature, precipitation and soil factors (e.g., organic matter, sub-surface material, texture, and drainage, depth of topsoil, topography, salinity and erosion.
SPI computing involves the above important factors in a more measurable and quantitative manner.
Localized factors considered in rating Agricultural Capability system focuses on one or two dominant limitation factors on a certain soil polygon. Apart from the above factors SPI Ratings are modified to account for local risk factors such as frequency of drought, frost, flooding and other natural hazards.
Relationship between rating and crop yield No direct connection to yield. Relationship between SPI and average yields is emphasized by MASC.
MASC has given all agricultural land in MB its own SPI for coverage purposes.
Limitation vs. Productivity Aiming to portray the level of limiting factors on crop production. Aiming to depict the productivity of a soil in measures of crop yields.
Polygon vs. quarter-section Used on soil-polygon basis Used on each quarter section basis i.e., each QTR receives a single rating.
Represented by the dominant soil in the polygon.
One Agricultural Capability rating is for one soil polygon. One SPI rating value is assigned for the whole quarter section which may contain multiple soil polygons that have several Agricultural Capability ratings.
SPI is QTR-section-unit based.

Suitability Ratings

Suitability ratings assess the appropriateness of a parcel of land for a specific purpose. Soil polygons are designated into by classes on the basis of physical and chemical characteristics and conditions with respect to permanent, productive irrigation agriculture.

Irrigation Suitability

This is a rating for general irrigated crop production. Soil and landscape characteristics such as texture, drainage, depth to water table, salinity, geological uniformity, topography and stoniness are considered. Classes are excellent, good, fair and poor.

A General Irrigation Suitability Rating (Table 1) is assigned based on the combined degree of limitation based on landscape features (Table 2) and degree of limitation based on soil features (Table 3). The system ranks soils based on their ability to sustain quality under long-term managed irrigation systems.

Table 1. Description of Irrigation Suitability Classes

General Rating Class Degree of Limitation Description
Excellent 1A No soil or landscape limitations These soils are medium textured, well drained and hold adequate available moisture. Topography is level to nearly level. Gravity irrigation methods may be feasible.
Good 1B 2A 2B Slight soil and/or landscape limitations The range of crops that can be grown may be limited. As well, higher development inputs and management are required. Sprinkler irrigation is usually the only feasible method of water application.
Fair 1C 2C 3A 3B 3C Moderate soil and/or landscape limitations Limitations reduce the range of crops that may be grown and increase development and improvement costs. Management may include special conservation techniques to minimize soil erosion, limit salt movement, limit water table build-up or flooding of depressional areas. Sprinkler irrigation is usually the only feasible method of water application.
Poor 1D 2D 3D 4A 4B 4C 4D Severe soil and/or landscape limitations Limitations generally result in a soil that is unsuitable for sustained irrigation. Some land may have limited potential when special crops, irrigation systems, and soil and water conservation techniques are used.

Table 2. Landscape Features Affecting Irrigation Suitability

Symbol Landscape Features Degree of Limitation
None (A) Slight (B) Moderate (C) Severe (D)
t1 Slope* - Simplex % < 2 2 - 9 > 9 - 20 > 20
t2 Slope* - Complex % 0 - 5 > 5 - 15 > 15
E Relief (m) (Average Local) < 1 1 - 3 >3 - 5 > 5
P Stoniness Classes Cover (%) 0, 1 & 2 (0 to 3%) 3 (> 3 to 15%) 4 (> 15 to 50%) 5 (> 50%)
I Inundation - Frequency of Flooding (period) 1 in 10 years 1 in 5 years Every year (annual-spring) Every year (seasonal)

* Suitability interpretations are based on the criteria for Complex slopes

Table 3. Soil Features Affecting Irrigation Suitability

Symbol Soil Feature Degree of Limitation
None (1) Slight (2) Moderate (3) Severe (4)
d Structure Granular, Single Grained, Prismatic, Blocky, Subangular Blocky Columnar, Platy Massive Massive
k Ksat (mm/hr) (0 - 1.2 m) > 50 50 - 15 < 15 - 1.5 < 1.5
x Drainability (mm/hr) (1.2 - 3 m) > 15 15 - 5 < 5 - 0.5 < 0.5
m

AWHC

Subhumid (mm/1.2 m) (% by volume)

> 120 (> 10)

120 - 100 (10 - 8)

< 100 - 75 (< 8 - 6)

< 75 (< 6)

Subarid (mm/1.2 m) (% by volume)

> 150 (> 12) 150 - 120 (12 - 10) < 120 - 100 (< 10 - 8) < 100 (< 8)
q Intake Rate (mm/hr) > 15 15 - 1.5 15 - 1.5 < 1.5
s

Salinity (mS/cm or dS/m) 0 - 0.6 m depth 0.6 - 1.2 m depth 1.2 - 3 m depth

< 2 < 4 < 8

2 - 4 4 - 8 8 - 16

> 4 - 8 > 8 - 16 > 16

> 8 > 16 > 16

n Sodicity (SAR)

0 - 1.2 m depth 1.2 - 3 m depth

< 6 < 6

6 - 9 6 - 9

> 9 - 12 > 9 - 12

>12 > 12

g

Geological Uniformity

(0 - 1.2 m)

1 Textural Group 2 Textural Groups Coarser below 2 Textural Groups Finer below 3 Textural Groups Coarser below 3 Textural Groups Finer below

(1.2 - 3 m)

2 Textural Groups 3 Textural Groups Coarser below 3 Textural Groups Finer below  
r Depth to Bedrock (m) > 3 3 - 2 < 2 - 1 < 1
h Depth to Water Table (m) > 2 2 - 1.2 (if salinity is a problem) 2 - 1.2 (if salinity is a problem) < 1.2
w Drainage Class Well, Moderately Well Imperfect Imperfect Poor, Very Poor, Excessive, Rapid
  * Texture (Classes) (0 - 1.2 m) L, SiL, VFSL, FSL CL, SiCL, SCL, SL, LVFS C, SC, SiC VFS, FS, LS, CoSL HvC GR, CoS, LCoS, S
  * Organic Matter % > 2 2 - 1 2 - 1 < 1
  * Surface Crusting Potential Slight Low Low Moderate

* Other important factors used to interpret type and degree of limitation but which do not present a limitation to irrigation themselves. No symbol is proposed for these factors since they will not be identified as subclass limitations. Rev. (2008)

Soil Suitability for Irrigated Potato Production

Soil polygon suitability for irrigation specific to potato production for processing are evaluated based on drainage, texture group of the entire profile, slope, stoniness and salinity. Class 1 soils are the most suitable, while Class 5 soils are the least suitable for this use.

A separate set of guidelines is used fro classifying rapid, well and moderately well drained soils (Table 4a) and imperfectly, poorly and very poorly drained soils (Table 4b).

In both the general irrigation suitability and suitability for irrigated potato production systems, the degree of suitability is determined by the most limiting or severe rating assigned to any one of the listed characteristics or properties.

Table 4a. Guidelines for Classifying Rapid, Well and Moderately Well Drained Soils

In assessing suitability of land for irrigated potato production, the degree of suitability is determined by the most restrictive or severe rating assigned to any one of the listed characteristics or properties.
Characteristic or Property

Suitability Rating

Class 1 Class 2 Class 3 Class 4 Class 5
Texture Group* CL CL/SF CL/SF/SC CL/FL/SF CL/LY LY/SF LY SY,SY/SC, SY/CL, SY/LY, SY/FL, SY/SS/LY, SF, SY/UD/LY, SF/CS, SF/SC, SF/LY, SF/FL, SC/LY, SC, SF/SS/FL, CL/FL, SC/FL, CL/SS/FL, LY/FL, LY/SC, LY/LS, LY/SS/SF, LY/SS/SC, LY/FL/SF, LY/SS/LY, LY/SS/FL, FL, FL/SF, FL/LY, FL/FL, FL/SY/SF, FL/SS/LY, FL/SS/FL, FL/CL SY/SS, SY/CY/LY, SF/SS, CL/SS, SF/CY, CL/CY, SF/CY/LY, CL/CY/LY, CL/SS/CY, LY/CY, LY/SS, FL/SS FL/CY, FL/CY/SF SK, SS, SS/RK, SS/LY, SS/FL, SS/CY, SC/RK, SF/RK, CS, CL/RK, CL/FR, CL/FR/RK, LS/RK, LY/RK, LY/SY/RK, FL/LY/RK, CY, CY/SS, CY/SC, CY/SY, CY/SF, CY/CL, CY/LY, CY/FL, CY/CY, CY/RK, CY/TX, CY/SS/CY, CY/LY/CY, CY/FL/CY, CY/LY/RK, CY/FL/RK, RK, TX, TX/LY, UD, UD/LY
Topography1 (Slope) 0 - 5% (a, b, c)

> 5 - 9% (d)

> 9% (e, f, g, h, i, j)

Stoniness2 Class -

St. 1

St. 2, 3, 4, 5

Salinity3 (mS/cm) < 2

0 - 4

> 4 - 8

> 8

Soil Order and/or Subgroup  

Orthic Regosol

  Organic Order, Solonetzic Order, Solonetzic Subgroups
Topography1 Stoniness2 (Surface covered) Salinity3 (mS/cm)
< 5 % level to very gently sloping - non-stony < 0.01 % very low 0 - 2
5 - 9 % gently sloping 1 slightly stony 0.01 - 0.1 % low > 2 - 4
> 9 % mod. to extremely sloping 2 moderately stony > 0.1 - 3 % weakly (s) > 4 - 8
  3 very stony > 3 - 15 % moderately (t) > 8 - 16
  4 exceedingly stony > 15 - 50 % strongly (u) > 16
  5 excessively stony > 50 %    
* SK = Skeletal SS = Sandy Skeletal LS = Loamy Skeletal CS = Clayey Skeletal  SC = Sandy Coarse SY = Sandy SF = Sandy Fine CL = Coarse Loamy LY = Loamy FL = Fine Loamy CY = Clayey RK = Bedrock FR = Fragmental UD = Undifferentiated TX = Texture Complex

Table 4b. Guidelines for Classifying Imperfectly, Poorly and Very Poorly Drained Soils

In assessing suitability of land for irrigated potato production, the degree of suitability is determined by the most restrictive or severe rating assigned to any one of the listed characteristics or properties.
Characteristic or Property

Suitability Rating

Class 1 Class 2 Class 3 Class 4 Class 5
Texture Group*     SY, SY/SS, SY/SC, SY/CL, SY/LY, SC/LY, SY/SS/LY, SY/UD/LY, SC, SF, SF/SS, SF/CS, SF/LY, SF/SC, SF/FL, SY/FL, SF/SS/FL, CL, CL/SS, CL/SF, CL/LY, CL/FL, CL/SF/SC, CL/SS/FL, CL/FL/SF, LY/SS, LY/SC, LY/SF, LY/LS, LY/SS/SF, LY/SF/SC, SC/FL, LY, LY/FL, LY/SS/LY, LY/SS/FL, FL, FL/SF, FL/SS, FL/CL, FL/LY, FL/FL, FL/SY/SF, FL/SS/LY, FL/SS/FL SF/CY, SY/CY/LYSF/CY/LY, SF/CY/FL, CL/CY, CL/CY/LY, CL/SS/CY, LY/CY, FL/CY/SF, FL/CY SK, SS, SS/RK, SS/LY, SS/FL, SS/CY, SC/RK, SF/RK, CS, CL/RK, CL/FR, CL/FR/RK, LS/RK, LY/RK, LY/SY/RK, FL/LY/RK, CY, CY/SS, CY/SC, CY/SY, CY/SF, CY/CL, CY/LY, CY/FL, CY/CY, CY/RK, CY/TX, CY/SS/CY, CY/LY/CY, CY/FL/CY, CY/LY/RK, CY/FL/RK, RK, TX, TX/LY, UD, UD/LY
Topography1 (Slope)   0 - 5%

> 5 - 9%

> 9%

Stoniness2 Class  

St. 1

St. 2, 3, 4, 5

Salinity3 (mS/cm)  

< 4

4 - 8

> 8

Soil Order and/or Subgroup Organic Order, Gleysolic Order, Solonetzic Order, Solonetzic Subgroups
Topography1 Stoniness2 (Surface covered) Salinity3 (mS/cm)
< 5 % level to very gently sloping - non-stony < 0.01 % very low 0 - 2
5 - 9 % gently sloping 1 slightly stony 0.01 - 0.1 % low > 2 - 4
> 9 % mod. to extremely sloping 2 moderately stony > 0.1 - 3 % weakly (s) > 4 - 8
  3 very stony > 3 - 15 % moderately (t) > 8 - 16
  4 exceedingly stony > 15 - 50 % strongly (u) > 16
  5 excessively stony > 50 %    
* SK = Skeletal SS = Sandy Skeletal LS = Loamy Skeletal CS = Clayey Skeletal SC = Sandy Coarse SY = Sandy SF = Sandy Fine CL = Coarse Loamy LY = Loamy FL = Fine Loamy CY = Clayey RK = Bedrock

FR = Fragmental UD = Undifferentiated TX = Texture Complex

The suitability of soil conditions and landscape features for irrigated potato production is based on soil resource information from detailed soil maps (1:20000 to 1:50000 scale) and soil databases. Each map is downloadable as a PDF file.

North CypressNorth NorfolkPortage la PrairieVictoriaSouth NorfolkGreyDufferinLorneLabroquerieSte AnneHanoverAlbertCameronWhitewaterEdwardArthurBrendaMortonWinchesterStanleyRhinelandRolandThompsonStrathconaArgyleLorneLouisePembina

Maps for Suitability for Irrigated Potato Production for Rural Municipalities of Manitoba

RM PDF file size

RM

PDF file size RM PDF file size RM PDF file size
Albert 299KB Argyle 141KB Arthur 483KB Brenda 356KB
Cameron 463KB Dufferin 417KB Edward 454KB Grey 414KB
Hanover 244KB La Broquerie 194KB Lorne 313KB Louise 388KB
Morton 398KB North Cypress 599KB North Norfolk 657KB Pembina 306KB
Portage 869KB Rhineland 454KB Roland 256KB South Norfolk 378KB
Springfield 607KB Stanley 342KB Ste. Anne 218KB Strathcona 309KB
Thompson 282KB Victoria 490KB Whitewater 255KB Winchester 342KB

Information considered in evaluating soil characteristics and landscape features are:

  • Soil texture and thickness and uniformity of deposits
  • Topography
  • Stoniness
  • Salinity
  • Soil drainage
  • Soil Order and Subgroup

Only the dominant soil series and landscape features for each polygon are used in the evaluation and in map production. Subdominant soil conditions and landscape features should also be considered when assessing a given land area for irrigated potato production.

The rating of soil and landscape characteristics for a given land area will assist in making an initial assessment of land suitability for irrigated potato production. The next step should involve an on-site investigation. Factors such as water supply, climate, agronomic practices, or economics that influence the decisions of whether land should or should not be used for irrigated potato production are not considered in this assessment.

Description of Suitability Classes

Class 1 - Lands in this group generally have the following characteristics:

  • soils are well to rapidly drained
  • soil textures usually range from loamy very fine sand, sandy loam to loam
  • soils are non-stony and have level to very gently sloping (0 to 5%) topography
  • salinity levels in the soil profile (0 ~60 cm) are very low

Class 2 - Lands in this group generally have the following characteristics:

  • soils are well to rapidly drained
  • soil materials usually include sandy (coarse) textures such medium and fine sand, loamy sand; and finer textures such as clay loam and silty clay loam
  • soils are nonstony and have level to very gently sloping (0 to 5%) topography
  • salinity levels in the soil profile (0 ~60 cm) are very low

Class 3 - Lands in this group generally have the following characteristics:

  • soils are well to rapidly drained
  • salinity levels in the soil profile (0 ~60 cm) range from 0 to 4 mS/cm (non-saline)
  • soil materials usually include sandy (coarse) textures such medium and fine sand, and loamy sand underlain by silty clay and clay materials; and finer textures such as loam, clay loam and silty clay loam underlain by coarse sand and gravel
  • soils are nonstony and have level to very gently sloping (0 to 5%) topography
  • soils are imperfectly drained
  • textures are similar to soils in class 1 and 2
  • salinity levels in the soil profile (0 ~60 cm) range from 0 to 4 mS/cm (non-saline)
  • soils are nonstony and have level to very gently sloping (0 to 5%) topography

Class 4 - Lands in this group generally have the following characteristics:

  • soils are well to imperfectly drained
  • salinity levels in the soil profile (0 ~60 cm) range from 4 to 8 mS/cm (weakly saline)
  • soils are slightly stony and have gently sloping topography (5 to 9%)
  • soil materials usually include a range of textures underlain by clay textured materials

Class 5 - Lands in this group generally may have one or more of the following characteristics:

  • salinity levels in the soil profile (0 ~60 cm) are greater than 8 mS/cm (moderately to strongly saline)
  • soils are moderately to excessively stony (st. 2,3,4,5) and have moderate to very steep slopes (greater than 9%)
  • soil textures are usually gravels, and/or clay; soils underlain by bedrock within 120 cm and soils with textural complexes, undifferentiated and fragmental materials
  • organic, gleysolic and solonetzic soils