Soils of the - Agriculture and Agri-Food Canada

subsoil : A general term for the layer of soil (or surficial geologic deposit) which, in the context of this report ,
underlies the surface and subsurface soil layers . It begins about 50 cm below the surface and continue s
downward for about 75 to 100 cm .
subsurface soil : A general term used in this report for the approximately 20 to 30 cm thick layer of soi l
underlying the surface soil .
surface soil : The uppermost part of the soil that is ordinarily moved in tillage, or its equivalent in uncultivate d
soils . In this report it refers to the upper 15 to 20 cm of the soil .
telluric seepage : Seepage moving through the soil on a plane more or less parallel to the land surface an d
often above a restricting area ; the waters are usually oxygenated .
terric layer : An unconsolidated mineral substratum underlying organic soil material .
texture, soil : The relative proportions of the various soil separates (sand, silt and clay) in a soil as described b y
the classes of soil texture . The names of textural soil classes may be modified by adding suitabl e
adjectives when coarse fragments are present in substantial amounts .
tidal flats : Areas of nearly flat, often barren mud periodically covered by tidal waters . Normally these material s
have an excess of soluble salt . A miscellaneous land type .
till (moraine) : Unstratified glacial drift deposited directly by the ice and consisting of clay, sand, gravel, an d
boulders intermingled in any proportion .
type, soil : A unit in the natural system of soil clasification ; a subdivision of a soil series consisting of o r
describing soils that are alike in all characteristics including the texture of the A horizon .
value, colour : The relative lightness of colour, which is approximately a function of the square root of the tota l
amount of light .
variant, soil : A soil whose properties are believed to be sufficiently different from other known soils to justify a
new name, but comprising such a limited geographic area that creation of a new named soil is not justified .
water table (groundwater) : Elevation at which the pressure in the water is zero with respect to the at -
mospheric pressure .
weathering : The physical and chemical disintegration, alteration, and decomposition of rocks and minerals a t
or near the earth's surface by atmospheric agents .
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