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Class 6 - Soils in this class are only capable of producing perennial forage crops, andimprovement practices are not feasible . These soils provide some sustained grazing for farmanimals, but the limitations are so severe, that improvements by use of farm machinery areimpractical . The terrain may be unsuitable for use of farm machinery, or the soils may not respondto improvement or the grazing season may be very short .Class 7 - Soils in this class have no capability for arable culture, or permanent, pasture .This class includes marsh, rockland and soil on very steep slopes .Soil Capability SubclassesSubclasses are divisions, within classes, that have the same kind oflimitations for agriculturaluse as a result of soil and climate . Thirteen different kinds of limitations have been recognized,at the subclass level, and are described in CLI Report No . 2 (14) . Only those subclasses used toclassify the soils of the Ville-Marie area are described .Subclass C Adverse climate caused by low temperatures .Subclass DSubclass FUndesirable soil structure and/or permeability.Low natural fertility, which may or may not be possible to correct by additions offertilizers or manure.Subclass I Inundation by flooding of streams or lakes limits agricultural use .Subclass MMoisture limitations due to low moisture-holding capacities, cause droughtiness thatlimits agricultural use .Subclass P Stoniness . Stones interfere with tillage, planting and harvesting .Subclass RShallowness to bedrock, which is less than one metre from the soil surface.Subclass S Adverse soil characteristics . Used when two or more of the limitations representedby Subclasses D, F or M are present, or when two of the limitations represented bySubclasses D, F or M are present and some additional limitation occurs, e .g. T.Subclass TAdverse topography due to steepness, or complexity ofslopes, limits agricultural use,by increasing the cost of farming over that on level land, by decreasing theuniformity of growth and maturity of crops, and by increasing the hazard of erosiondamage by water .Subclass W Excess water, other than from flooding, limits use for agriculture . The excess watermay be due to poor drainage, a high water table, seepage, or runoff fromsurrounding areas .AssumptionsBefore using the soil capability tables, it is important that the user have an understandingof the following assumptions, upon which the classification is based :(a)The soils will be well-managed and cropped under a largely mechanized system.(b) Land requiring improvements, e.g. drainage, that can be done economically by the farmerhimself, is classed according to its limitations or hazards, in use, after the improvementshave been made.