Soils of the - Agriculture and Agri-Food Canada

Organic : An order of soils that have developed dominantly from organic deposits . The majority of Organi c
soils are saturated for most of the year, unless artificially drained, but some of them are not usuall y
saturated for more than a few days . They contain 17% or more organic carbon .
organic matter, soil : The organic fraction of the soil ; includes plant and animal residues at various stages o f
decomposition, cells and tissues of soil organisms, and substances synthesized by the soil population .
ortstein : (i) An indurated layer in the B horizon of Podzols in which the cementing material consists of illuviate d
sesquioxides and organic matter. (ii) As a subgroup of Podzolic soils, Ortstein indicates a Bhfc or Bfc
horizon that is strongly cemented, occurs over at least one-third of the exposure, and is at least 2 .5 cm ( 1
inch) thick .
outwash, glacial : Sediments carried by, and deposited from flowing water beyond a glacier front and lai d
down as stratified drift in thin foreset beds . The particle size may vary from boulders to silt .
pans : Horizons or layers in soils that are strongly compacted, indurated, or very high in clay content .
parent material : The unconsolidated and more or less unweathered mineral or organic matter from which th e
solum of a soil has developed by pedogenic processes .
peat : Unconsolidated soil material consisting largely of undecomposed, or only slightly decomposed ,
organic matter.
ped : A unit of soil structure such as a prism, block, or granule, which is formed by natural processes, i n
contrast with a clod, which is formed artificially.
podgenic : Of or referring to the genesis (formation and development) of soil ; used mainly when discussing th e
kind, strength and distribution of soil horizons in a soil profile .
pedology : The aspects of soil science dealing with the origin, morphology, genesis, distribution, mapping ,
and taxonomy of soils, and classification in terms of their use .
perched water table : A water table due to the "perching" of water on a relatively impermeable layer at som e
depth within the soil . The soil within or below the impermeable layer is not saturated with water .
percolation (of soil water) : The downward movement of water through soil .
permeability, soil : The ease with which gases and liquids penetrate or pass through a bulk mass of soil or a
layer of soil . Because different soil horizons vary in permeability, the specific horizon should b e
designated .
perviousness : The potential of a soil to transmit water internally, as inferred from soil characteristics .
pH, soil : The negative logarithm of the hydrogen ion activity of a soil ; the degree of acidity or alkalinity of a soil .
phase, soil : A subdivision of a soil type or other unit of classification having characteristics that affect the us e
and management of the soil, but that do not vary sufficiently to differentiate it as a separate type .
plastic limit (Atterberg limit) : (i) The water content corresponding to an arbitrary limit between the plastic an d
the semisolid states of consistence of a soil . (ii) The water content at which a soil will just begin to crumbl e
when rolled into a thread approximately 3 mm in diameter .
platy : Consisting of soil aggregates that have developed predominantly along the horizontal axes ; laminated ;
flaky.
Podzolic : An order of soils having podzolic B horizons (Bh, Bhf,or Bf) in which amorphous combinations o f
organic matter (dominantly fulvic acid), Al, and usually Fe are accumulated . The sola are acid and the B
horizons have a high pH-dependent charge . The great groups in the order are Humic Podzol, Ferro-Humi c
Podzol, and Humo-Ferric Podzol .
pore space : The total space not occupied by soil particles in a bulk volume of soil .
prismatic : A soil structure type having prismlike aggregates that have vertical axes much longer than the
horizontal axes .
profile, soil : A vertical section of the soil through all its horizons and extending into the parent material .
reaction, soil : The degree of acidity or alkalinity of a soil, usually expressed as a pH value .
regolith : The unconsolidated mantle of weathered rock and soil material overlying solic rock .
Regosolic : An order of soils having no horizon development or development of the A and B horizon s
insufficient to meet the requirements of the other soil orders .
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