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Agriculture Capability Detailed Description

Explanatory Notes

In this classification, mineral and organic soils are each grouped into seven classes on the basis of soil and climate characteristics according to their potentials and limitations for agricultural use. Lands in Classes 1 to 4 inclusive are considered capable of sustained production of common cultivates field crops. The need for management practises increases, and/or the possible range of crops decreases, from Class 1 to Class 4. Class 5 lands are capable of use only for the producing perennial forage crops or specially adapted crops. Class 6 lands are capable of providing only sustained natural grazing for domestic livestock. Class 7 lands are incapable of use for either arable culture or grazing.

This classification takes into account the relative degree and type of limitation or hazard to agriculture; use and/or the range of possible crops. It also indicates the type and intensity of management practises requires for good management of the soil resource to maintain sustained production. Productivity (i.e. yield per hectare) of any specific crop is not considered.

Important factors on which the classification is based are:

  1. The soils will be managed and cropped under a largely mechanised system.

  2. This classification provides most lands with two ratings — one under improved conditions and one for improved conditions. Unimproved ratings are based on the conditions that exist at the time of the survey, without irrigation. Improved ratings indicate the capability after existing limitations and/or hazards have been adequately alleviated. Improvements which are to be considered include drainage, irrigation, diking, stone removal, salinity alleviation, subsoiling, and/or the intensive addition of fertilizers or other soil amendments.

  3. In determining improved ratings, irrigation water is assumed to be available. Other types of improvement are considered drainage, stone removal, fertilization, diking, salinity alleviation, subsoiling and the addition of soil amendments. The extent to which these improvements can increase the land capability is determined from site specific assessments.

  4. The following are not considered in the classification: distance to market, available transportation facilities, location, farm size, type of ownership, cultural patterns, skill or resources of individual operators, and hazard of crop damage by storms.

  5. The classification does not include capability of lands for trees, tree fruits, grapes, ornamental plants, recreation, or wildlife.

The agriculture capability classification consists of two main components: (1) the capability class, and (2) the capability subclass. The capability class and subclass together provide information about the degree and kind of limitation for agricultural use. In addition to land capability designation, they are also useful for land use planning and assessing of management needs.

The detailed methodology for determining capability classification outlined here is contained in MOE Manual 1, 1983. Click here for infomation on obtaining agriculture capability or soil maps.

 

Capability Classes

The capability class, the broadest category in the classification, is a grouping of lands that have the same relative degree of limitation or hazard for agricultural use. The intensity of the limitation or hazard becomes progressively greater from Class 1 to Class 7. The class indicates the general suitability of the land for agricultural use.

Two sets of classes exist, one for mineral soils and one for organic soils. The classes are as follows:

LAND CAPABILITY CLASSES FOR MINERAL SOILS

The seven land capability classes for mineral soils are defined and described as follows:

CLASS 1  LAND IN THIS CLASS EITHER HAS NO OR ONLY VERY SLIGHT LIMITATIONS THAT RESTRICT ITS USE FOR THE PRODUCTION OF COMMON AGRICULTURAL CROPS.
Land in Class 1 is level or nearly level. The soils are deep, well to imperfectly drained under natural conditions, or have good artificial water table control, and hold moisture well. They can be managed and cropped without difficulty. Productivity is easily maintained for a wide range of field crops.
 
CLASS 2  LAND IN THIS CLASS HAS MINOR LIMITATIONS THAT REQUIRE GOOD ONGOING MANAGEMENT PRACTISES OR SLIGHTLY RESTRICT THE RANGE OF CROPS, OR BOTH.
Land in class 2 has limitations which constitute a continuous minor management problem or may cause lower crop yields compared to Class 1 land but which does not pose a threat of crop loss under good management. The soils in Class 2 are deep, hold moisture well and can be managed and cropped with little difficulty.
 
CLASS 3  LAND IN THIS CLASS HAS LIMITATIONS THAT REQUIRE MODERATELY INTENSIVE MANAGEMENT PRACTISES OR MODERATELY RESTRICT THE RANGE OF CROPS, OR BOTH.
The limitations are more severe than for Class 2 land and management practises are more difficult to apply and maintain. The limitations may restrict the choice of suitable crops or affect one or more of the following practises: timing and ease of tillage, planting and harvesting, and methods of soil conservation.
 
CLASS 4  LAND IN THIS CLASS HAS LIMITATIONS THAT REQUIRE SPECIAL MANAGEMENT PRACTISES OR SEVERELY RESTRICT THE RANGE OF CROPS, OR BOTH.
Land in Class 4 has limitations which make it suitable for only a few crops, or the yield for a wide range of crops is low, or the risk of crop failure is high, or soil conditions are such that special development and management practises are required. The limitations may seriously affect one or more of the following practises: timing and ease of tillage, planting and harvesting, and methods of soil conservation.
 
CLASS 5  LAND IN THIS CLASS HAS LIMITATIONS THAT RESTRICT ITS CAPABILITY TO PRODUCING PERENNIAL FORAGE CROPS OR OTHER SPECIALLY ADAPTED CROPS.
Land in Class 5 is generally limited to the production of perennial crops or other specially adapted crops. Productivity of these suited crops may be high. Class 5 lands can be cultivated and some may be used for cultivated field crops provided unusually intensive management is employed and/or the crop is particularly adapted to the conditions peculiar to these lands. Cultivated field crops may be grown on some Class 5 land where adverse climate is the main limitation, but crop failure can be expected under average conditions. Note that in areas which are climatically suitable for growing tree fruits and grapes the limitations of stoniness and/or topography on some Class 5 lands are not significant limitations to these crops.
 
CLASS 6  LAND IN THIS CLASS IS NONARABLE BUT IS CAPABLE OF PRODUCING NATIVE AND OR UNCULTIVATED PERENNIAL FORAGE CROPS.
Land in Class 6 provides sustained natural grazing for domestic livestock and is not arable in its present condition. Land is placed in this class because of severe climate, or the terrain is unsuitable for cultivation or use of farm machinery, or the soils do not respond to intensive improvement practises. Some unimproved Class 6 lands can be improved by draining and/or diking.
 
CLASS 7  LAND IN THIS CLASS HAS NO CAPAPBILITY FOR ARABLE OR SUSTAINED NATURAL GRAZING.
All classified areas not included in Classes 1 to 6 inclusive are placed in this class. Class 7 land may have limitations equivalent to Class 6 land but they do not provide natural sustained grazing by domestic livestock due to climate and resulting unsuitable natural vegetation. Also included are rockland, other nonsoil areas, and small water-bodies not shown on maps. Some unimproved Class 7 land can be improved by draining or diking.
 

LAND CAPABILITY FOR ORGANIC SOILS

Organic soils are grouped into seven classes, designated as 01 to 07. The organic soil class definitions are equivalent in terms of their relative capabilities and limitations for agricultural use to those defined for mineral soil.


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Capability Subclasses

The subclass indicates lands with similar kinds but varying intensities of limitations and hazards. It provides information on the kind of management problem or use limitation. Except for Class 1 and O1 lands, which have no significant limitations, the capability classes are divided by subclasses on the basis of type of limitation to agricultural use. Each class can include many different kinds of soil, similar with respect to degree of limitation: but soils in any class may require unlike management and treatment as indicated by the subclasses shown. For detailed definitions and guidelines refer to MOE Manual 1, 1983.

LAND CAPABILITY SUBCLASSES FOR MINERAL SOILS

A SOIL MOISTURE DEFICIENCY:
Crops are adversely affected by droughtiness caused by soil and/or climate characteristics. Improved by irrigation.
 
*C ADVERSE CLIMATE:
Thermal limitations to plant growth. Minimum temperature near freezing and/or insufficient heat units during the growing season and/or extreme minimum temperatures during the winter season. NOT IMPROVABLE.
 
D UNDESIRABLE SOIL STRUCTURE AND/OR LOW PERVIOUSNESS:
Soils are difficult to till, require special management for seedbed preparation, pose trafficability problems, have insufficient aeration, absorb and distribute water slowly, and/or have the depth of rooting zone restricted by conditions other than high water table, bedrock, or permafrost. Improvement practises vary; no improvement is assumed in the absence of local experience.
 
E EROSION:
Past damage from erosion limits agricultural use due to loss of productivity and hampering of access by gullies. NOT IMPROVABLE.
 
*F FERTILITY:
Lack of available nutrients, low cation exchange capacity or nutrient holding ability, high acidity or alkalinity, high levels of carbonates, presence of toxic elements or compounds, or high fixation of plant nutrients. Usually improvable through fertilizers and amendments.
 
*I INUNDATION:
Overflow by streams, lakes or marine tides causes crop damage or restricts agriculture use. Improvable by diking if a major reclamation project is not required.
 
M MOISTURE:
A low moisture holding capacity, caused by adverse inherent soil characteristics, limits crop growth. (Not to be confused with climatic drought.)
 
*N SALINITY:
Soluble salts in the soil reduce crop growth or restrict the range of crops. Improvement practises and their success in alleviating limitations due to salinity vary depending on site and soil conditions.
 
P STONINESS:
Coarse fragments significantly hinder tillage, planting and harvesting. Note that in areas which are climatically suitable for growing tree fruits and grapes, a Class 5 level stoniness limitation may not be a significant limitation to these crops.
 
R DEPTH TO SOLID BEDROCK:
Bedrock near or t the surface restrict rooting depth and cultivation. NOT IMPROVABLE.
 
T TOPOGRAPHY:
Steepness or the pattern of slopes hinders the use of farm machinery, decreases the uniformity of growth and maturity of crops, and/or increases the potential for water erosion. NOT IMPROVABLE. Note that in areas which are climatically suitable for growing tree fruits and grapes, a Class 5 level topography limitation may not be considered a significant limitation to these crops.
 
*W EXCESS WATER:
Excess free water, other than from flooding, limits agricultural use and may be due to poor drainage, high water tables, seepage, and/or runoff from surrounding areas. Improvable by drainage; feasibility and level of improvement is assessed on a site-specific basis.
 
*Z PERMAFROST:
Permafrost maintains undesirably cold soil temperatures and causes drainage and subsidence problems when it is near the surface. NOT IMPROVABLE.
 

LAND CAPABILITY SUBCLASSES FOR ORGANIC SOILS

B WOOD IN THE PROFILE:
Layers of wood interfere with cultivation and/or with ditching and drain installation. No improvement is assumed in the absence of local expertise.
 
H DEPTH OF ORGANIC SOIL OVER BEDROCK AND/OR ROCKINESS:
Bedrock near the surface restricts rooting depth and the feasibility of subsurface drainage, and/or rock outcrops restrict agricultural use. NOT IMPROVABLE.
 
L DEGREE OF DECOMPOSITION — PERMEABILITY:
Degree of decomposition affects drainage, permeability capillary rise of water and rate of subsidence. Layers of mineral soil in an organic profile may pose a limitation to optimum crop yield and to drainage. NOT IMPROVABLE.

* These subclasses are the same for both organic soils and mineral soils.


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References

  1. Canada Land Inventory. 1972. Reprint. Soil Capability Classification for Agriculture. Report No. 2. Department of the Environment. Ottawa, Ontario. 16 pp. [Available here]

  2. Climatology Unit. 1981. Climate Capability Classification for Agriculture in British Columbia. APD Technical Paper 4. Air Studies Branch, British Columbia Ministry of Environment. Victoria, B.C. 23 pp. [Available here]

  3. Kenk, E. and I. Cotic. April, 1983. Land Capability Classification for Agriculture in British Columbia. MOE Manual 1. Surveys and Resource Mapping Branch, Ministry of Envirnoment and Soils Branch, Ministry of Agriculture and Food. Kelowna, B.C. 68 pp. ISSN 0821-0640 [Available here]

  4. Runka, G.G. 1973. Methodology — Land Capability for Agriculture — British Columbia Land Inventory (CLI). Soil Survey Division, British Columbia Department of Agriculture. Kelowna, B.C. 25 pp. [Available here]

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