Soils of the - Agriculture and Agri-Food Canada

lithic layer : Bedrock under the control section of a soil . In Organic soils, bedrock occurring within a depth o f
between 10 cm and 160 cm from the surface, while in mineral soils it occurs between 10 and 100 cm of th e
surface .
loamy : Intermediate in texture and properties between fine-textured and coarse-textured soils . It includes al l
textural classes having "loam" or "loamy" as a part of the class name, such as clay loam or loamy sand .
loess : Material transported and deposited by wind and consisting of predominantly silt-sized particles .
Luvisolic : An order of soils that have eluvial (Ae) horizons, and illuvial (Bt) horizons in which silicate clay is th e
main accumulation product . The soils developed under forest or forest-grassland transition in a moderate
to cool climate .
map, soil : A map showing the distribution of soil mapping units related to the prominent physical and cultura l
features of the earth's surface .
medium texture : Intermediate between fine-textured and coarse-textured soils . It includes the followin g
textural clases : very fine sandy loam, loam, silt loam, and silt .
mesic layer : A layer of organic material at a stage of decomposition between that of the fibric and humi c
layers .
metamorphic rock : Rock derived from pre-existing rocks, but differing from them in physical, chemical, an d
mineralogical properties as a result of natural geological processes, principally heat and pressure ,
originating within the earth . The pre-existing rocks may have been igneous, sedimentary, or another for m
of metamorphic rock .
mineral soil : A soil consisting predominantly of, and having its properties determined predominantly by ,
mineral matter. It contains less than 17% organic carbon except for an organic surface layer that may b e
up to 40 cm thick .
miscellaneous land type : A mapping unit for areas of land that have little or no natural soil .
moder : A zoogenous forest humus form made up of plant remains partly disintegrated by the soil fauna ( F
layer), but not matted as in raw humus . It is transitional to a zone of spherical or cylindrical microejections o f
arthropods that is permeated by loose mineral particles in its lower part and often throughout . Incorpora -
tion of organic matter is shallow and the mixing of organic and mineral particles is purely mechanical .
moderately coarse texture : Consisting predominantly of coarse particles . In soil textural classification, i t
includes all the sandy loams except very fine sandy loam .
moderately fine texture : Consisting predominantly of intermediate-sized soil particles with or without smal l
amounts of fine or coarse particles . In soil textural classification, it includes clay loam, sandy clay loam ,
and silty clay loam .
moraine (glacial till) : The materials transported beneath, beside, on, within and in front of a glacier ;
deposited directly from the glacier and not modified by any intermediate agent .
morphology, soil : (i) The physical constitution, particularly the structural properties, of a soil profile a s
exhibited by the kinds, thickness, and arrangement of the horizons in the profile, and by the texture ,
structure, consistence, and porosity of each horizon . (ii) The structural characteristics of the soil or any o f
its parts .
mottles : Spots or blotches of different colour or shades of colour interspersed with the dominant colour . The y
are described in terms of abundance (few, common, many), size, (fine, medium, coarse) and contras t
(faint, distinct, prominent) . Mottling in soils indicates poor aeration and lack of good drainage .
mottling : Formation or presence of mottles in the soil .
mull : A zoogenous forest humus form consisting of an intimate mixture of well-humified organic matter an d
mineral soil that makes a gradual transition to the horizon underneath . It is distinguished by its crumb o r
granular structure, and because of the activity of the burrowing microfauna, partly decomposed organi c
debris does not accumulate as a distinct layer (F layer) as in mor and moder .
Munsell colour system : A colour designation system specifying the relative degrees of the three simpl e
variables of colour : hue, value, and chroma .
order, soil : The highest category in the Canadian system of soil classification . All the soils of Canada have
been divided into nine orders : Chernozemic, Solonetzic, Luvisolic, Podzolic, Brunisolic, Regosolic ,
Gleysolic, Organic, and Cryosolic . All the soils within an order have one or more characteristics i n
common .
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