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Overview

The LSRS Model breaks apart the required information into:

  • Soil,
  • Landscape, and
  • Climate.

This is illustrated in the diagram below. Each of these components are handled separately and the resulting information aggregated to produce a final rating.

LSRS Inputs / Outputs

 

The LSRS ratings produced utilize the familiar 1 - 7 rating system. This was a conscious decision since the ratings are familiar and appear in various legislation. The table below outlines the rating system.

 

LSRS Suitability Class Ratings
Rating Limitations Comments
1 none to slight Land with these ratings may be utilized on a continuous basis.
2 slight
3 moderate
4 severe  
5 very severe  
6 extremely severe  
7 unsuitable  

Limitations

Different limitations may be associated with class designations. The tables below provide a summary.

CLIMATE LIMITATIONS:

Temperature (H) Inadequate heat units
Moisture (A) Inadequate moisture

SOIL LIMITATIONS:

Water holding capacity/texture (M) Lack of water due to inherent soil characteristics
Soil structure (D) Soil structure that limits the depth of rooting, or by surface crusting that limits the emergence of shoots. Root restriction by bedrock and by a high water table are considered separately (see Rock and Drainage).
Organic matter (F) Mineral soil with a low organic matter content in the Ap or Ah horizon (often considered a fertility factor)
Depth of topsoil (E) Mineral soil with a thin Ap or Ah horizon (often resulting from erosion)
Soil reaction (V) A pH value either too high or too low
Salinity (N) Soluble salts sufficient to have an adverse effect
Sodicity (Y) Amounts of exchangeable sodium sufficient to have an adverse effect
Organic surface (0) Mineral soils having a peaty surface layer up to 40 cm thick
Drainage (W) Excess water (not due to inundation)
Organic soil temperature (Z) Organic soils - where the regional climate has less than 1600 Effective Growing Degree Days (EGDD)
Rock (R) Bedrock sufficiently close to the surface to have an adverse effect
Degree of Decomposition or Fibre Content (B) Organic soils - degree of decomposition of the organic material is not optimum
Depth and Substrate (G) Shallow organic soils with underlying material that is not optimum

 

LANDSCAPE LIMITATIONS:

 

 

Slope (T) Slopes steep enough to incur risk of water erosion or to limit cultivation
Landscape Pattern (K) Areas with strongly contrasting soils and/or non-arable obstacles that limit production substantially impact management practices
Stoniness and Coarse Fragments (P) Land that is stony (fragments coarser than 7.5 cm) or gravelly (fragments smaller than 7.5 cm diameter) so as to hinder tillage or limit production
Wood content (J) Organic soils - content of wood or Eriophorum species sufficient to limit production
Inundation (I) Land areas subject to inundation or flooding that limits production

 

Ratings Format

Ratings usually consist of one to three components. The first component reports the rating for the largest area. This is followed by the next largest area and so on. In a similar fashion each class rating can be followed by one, two, or three limitations (most significant to least). Limitations are shown only if they are significant. It is possible that an area has many limitations but none of them are significant, so nothing "stands out" and as a result, no limitation is reported.

Rating Example

An example rating follows (this is for a soil area east of Edmonton, Alberta and was derived using the Canola model component of LSRS and the AGRASID soil information):

2HT(6) - 6W(4)

60% of the area is Class 2 with primary limitation H (inadequate heat) and secondary limitation T (steep slope).

40% of the area is Class 6 with primary limitation W (excess water).

Special Cases

The LSRS program makes a special case for Water Bodies (e.g., lakes) and reports them as "WB" rather than using the 1 to 7 class designations oultined above.

In a similar fashion, Disturbed Lands (for Alberta) is reported as "DL".