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Definitions of formative elements for lower level units

The definitions of diagnostic horizons and properties, given in italics below, are those presented in Chapter 3, unless stated otherwise.

In most situations only a limited number of combinations will be possible, as most of the definitions are mutually exclusive.

TABLE 3 Alphabetical list of lower level soil names


Abruptic


Ferralic


Lixic


Rhodic


Aceric


Ferric


Luvic


Rubic


Acric


Fibric


Magnesic


Ruptic


Acroxic


Folic


Mazic


Rustic


Albic


Fluvic


Melanic


Salic


Alcalic


Fragic


Mesotrophic


Sapric


Alic


Fulvic


Mollic

100

Silic


Alumic


Garbic

70

Natric


Siltic


Andic

40

Gelic


Nitic


Skeletic

10

Anthraquic


Gelistagnic


Ochric


Sodic


Anthric


Geric


Ombric


Spodic


Anthropic


Gibbsic


Oxyaquic


Spolic


Arenic


Glacic


Pachic


Stagnic


Aric


Gleyic


Pellic


Sulphatic


Aridic


Glossic


Petric


Takyric


Arzic


Greyic


Petrocalcic


Tephric


Calcaric


Grumic


Petroduric

110

Terric


Calcic


Gypsic

80

Petrogypsic


Thionic


Carbic

50

Gypsiric


Petroplinthic


Toxic

20

Carbonatic


Haplic


Petrosalic


Turbic


Chernic


Histic


Placic


Umbric


Chloridic


Hortic


Plaggic


Urbic


Chromic


Humic


Planic


Vetic


Cryic


Hydragric


Plinthic


Vermic


Cutanic


Hydric


Posic


Vertic


Densic


Hyperochric


Profondic


Vitric


Duric


Hyperskeletic


Protic

120

Xanthic


Dystric


Irragric

90

Reductic


Yermic


Entic

60

Lamellic


Regic



30

Eutric


Leptic


Rendzic




Eutrisilic


Lithic


Rheic



Where relevant, the names can be defined further using prefixes, for example Epigleyi-, Protothioni-. The following prefixes can be used:


Bathi


Epi


Orthi


Thapto


Cumuli


Hyper


Para




Endo


Hypo


Proto



Abruptic

having an abrupt textural change.

Aceric

having a pH (1:1 in water) between 3.5 and 5 and jarosite mottles within 100 cm from the soil surface (in Solonchaks only).

Acric

having a ferralic horizon which meets the clay increase requirements of an argi some horizon, and which has a base saturation (by 1 M NH4OAc) of less than 50 percent in at least part of the B horizon within 100 cm from the soil surface (in Ferralsols only).

Acroxic

having less than 2 cmolc kg-1 fine earth exchangeable bases plus 1 M KCl exchangeable Al3+ in one or more horizons with a combined thickness of 30 cm or more within 100 cm from the soil surface (in Andosols only).

Albic

having an albic horizon within 100 cm from the soil surface.

Hyperalbic

having an albic horizon within 50 cm from the soil surface and the lower boundary at a depth of 100 cm or more from the soil surface.

Glossalbic

showing tonguing of an albic into an argic or natric horizon.

Alcalic

having a pH (1:1 in water) of 8.5 or more within 50 cm from the soil surface.

Alic

having an argic horizon which has a cation exchange capacity equal to or more than 24 cmolc kg-1 clay throughout, a silt/clay ratio of less than 0.6, and an Alsaturation of 50 percent or more.

Alumic

having an Al-saturation of 50 percent or more in at least some part of the B horizon between 50 and 100 cm from the soil surface.

Andic

having an andic horizon within 100 cm from the soil surface.

Aluandic

having an andic horizon with an acid oxalate (pH 3) extractable silica content of less than 0.6 percent, or an Alpy30/Alox31 ratio of 0.5 or more.
30 Alpy pyrophosphate extractable aluminium.
31 Alox: acid oxalate (pH 3) extractable aluminium (method of Blakemore et al, 1981).

Silandic

having an andic horizon with an acid oxalate (pH 3) extractable silica content of 0.6 percent or more, or an Alpy/Alox ratio of less than 0.5.

Anthraquic

having an anthraquic horizon.

Anthric

showing evidence of human influence caused by cultivation practices.

Anthropic

consisting of anthropogeomorphic soil material, or showing profound modification of the soil by human activity caused by other factors than those related to cultivation (in Regosols only).

Aric

having only remnants of diagnostic horizons caused by repeated deep ploughing.

Arenic

having a texture of loamy fine sand or coarser throughout the upper 50 cm of the soil.

Aridic

having aridic properties without a takyric or yermic horizon.

Arzic

having sulphate-rich groundwater within 50 cm from the soil surface at some period in most years and containing 15 percent or more gypsum averaged over a depth of 100 cm (in Gypsisols only).

Calcaric

calcareous at least between 20 and 50 cm from the soil surface.

Calcic

having a calcic horizon or concentrations of secondary carbonates between 50 and 100 cm from the soil surface.

Hypercalcic

having a calcic horizon which contains 50 percent or more calcium carbonate equivalent.

Hypocalcic

having only concentrations of secondary carbonates within 100 cm from the soil surface.

Orthicalcic

having a calcic horizon within 100 cm from the soil surface.

Carbic

having a cemented spodic horizon which does not contain enough amorphous iron to turn redder on ignition (in Podzols only).

Carbonatic

having a soil solution with pH > 8.5 (1:1 in water) and HCO3 > SO4 > > Cl (in Solonchaks only).

Chernic

having a chernic horizon (in Chernozems only).

Chloridic

having a soil solution (1:1 in water) with Cl > > SO4 > HCO3 (in Solonchaks only).

Chromic

having a B horizon which in the major part has a Munsell hue of 7.5YR and a chrome, moist, of more than 4, or a hue redder than 7.5YR.

Cryic

having a cryic horizon within 100 cm from the soil surface.

Cutanic

having clay skins in the argic horizon (in Luvisols only).

Densic

having a cemented spodic horizon ("ortstein") (in Podzols only).

Duric

having a duric horizon within 100 cm from the soil surface.

Dystric

having a base saturation (by 1 M NH4OAc) of less than 50 percent in at least some part between 20 and 100 cm from the soil surface, or in a layer 5 cm thick directly above a lithic contact in Leptosols.

Epidystric

having a base saturation (by 1 M NH4OAc) of less than 50 percent at least between 20 and 50 cm from the soil surface.

Hyperdystric

having a base saturation (by 1 M NH4OAc) of less than 50 percent in all parts between 20 and 100 cm from the soil surface, and less than 20 percent in some part within 100 cm from the soil surface.

Orthidystric

having a base saturation (by 1 M NH4OAc) of less than 50 percent in all parts between 20 and 100 cm from the soil surface.

Entic

lacking an albic horizon and having a loose spodic horizon (in Podzols only).

Eutric

having a base saturation (by 1 M NH4OAc) of 50 percent or more at least between 20 and 100 cm from the soil surface, or in a layer 5 cm thick directly above a lithic contact in Leptosols.

Endoeutric

having a base saturation (by 1 M NH4OAc) of 50 percent or more in all parts between 50 and 100 cm from the soil surface.

Hypereutric

having a base saturation (by 1 M NH4OAc) of 80 percent or more in all parts between 20 and 100 cm from the soil surface.

Orthieutric

having a base saturation (by 1 M NH4OAc) of 50 percent or more in all parts between 20 and 100 cm from the soil surface.

Eutrisilic

having a sil-andic horizon and a sum of exchangeable bases of 25 cmolc kg-1 fine earth within 30 cm from the soil surface.

Ferralic

having ferralic properties within 100 cm from the soil surface.

Hyperferralic

having a cation exchange capacity (by 1 M NH4OAc) of less than 16 cmolc kg-1 clay in at least some subhorizons within 100 cm from the soil surface.

Hypoferralic

having a cation exchange capacity (by 1 M NH4OAc) of less than 4 cmolc kg-1 fine earth in at least 30 cm of the upper 100 cm of the soil, and a Munsell colour chrome, moist, of 5 or more and/or hues redder than 10YR (in Arenosols only).

Ferric

having a ferric horizon within 100 cm from the soil surface.

Hyperferric

having one or more layers with a total thickness of 25 cm or more consisting of 40 percent or more iron/manganese-oxide nodules within 100 cm from the soil surface.

Fibric

having more than two-thirds (by volume) of the organic soil material consisting of recognizable plant tissue (in Histosols only).

Folic

having a folic horizon (in Histosols only).

Fluvic

haying fluvic soil materials within 100 cm from the soil surface.

Fragic

having a fragic horizon within 100 cm from the soil surface.

Fulvic

having a fulvic horizon within 30 cm from the soil surface.

Garbic

having accumulations of anthropogeomorphic soil material containing more than 35 percent (by volume) organic waste materials (in Anthropic Regosols only).

Gelic

having permafrost within 200 cm from the soil surface.

Gelistagnic

having temporary water saturation at the surface caused by a frozen subsoil.

Geric

having geric properties in at least some horizon within 100 cm from the soil surface.

Gibbsic

having a layer more than 30 cm thick containing more than 25 percent gibbsite in the fine earth fraction within 100 cm from the soil surface.

Glacic

having a horizon within 100 cm from the soil surface which is 30 cm or more thick and contains 95 percent or more (by volume) ice.

Gleyic

having gleyic properties within 100 cm from the soil surface.

Endogleyic

having gleyic properties between 50 and 100 cm from the soil surface.

Epigleyic

having gleyic properties within 50 cm from the soil surface.

Glossic

showing tonguing of a mollic or umbric horizon into an underlying B horizon or into the saprolite.

Molliglossic

showing tonguing of a mollic horizon into an underlying B horizon or into the saprolite.

Umbriglossic

showing tonguing of an umbric horizon into an underlying B horizon or into the saprolite.

Greyic

having uncoated silt and sand grains on structural pedfaces in a mollic horizon (in Phaeozems only).

Grumic

having a surface layer with a thickness of 3 cm or more with a strong structure finer than very coarse granular (in Vertisols only).

Gypsic

having a gypsic horizon within 100 cm from the soil surface.

Hypergypsic

having a gypsic horizon which has 60 percent or more gypsum.

Hypogypsic

having a gypsic horizon which has 25 percent or less gypsum.

Gypsiric

having gypsiric soil material at least between 20 and 50 cm from the soil surface.

Haplic

having a typical expression of certain features (typical in the sense that there is no further or meaningful characterization).

Histic

having a histic horizon within 40 cm from the soil surface.

Fibrihistic

having a histic horizon within 40 cm from the soil surface, in which more than two-thirds (by volume) of the organic soil material consist of recognizable plant tissue.

Saprihistic

having a histic horizon within 40 cm from the soil surface, in which less than one-sixth (by volume) of the organic soil material consists of recognizable plant tissue and which has a very dark grey to black colour.

Thaptohistic

having a buried histic horizon between 40 and 100 cm from the soil surface.

Hortic

having a hortic horizon; in Anthrosols 50 cm or more thick, in other soils less than 50 cm thick.

Humic

having a high organic carbon content; in Ferralsols and Nitisols more than 1.4 percent (by weight) organic carbon in the fine earth fraction as weighted average over a depth of 100 cm from the soil surface, in Leptosols more than 2 percent (by weight) organic carbon in the fine earth fraction to a depth of 25 cm from the soil surface, and in other soils more than 1 percent (by weight) organic carbon in the fine earth fraction to a depth of 50 cm from the soil surface.

Mollihumic

having the organic carbon content as defined above and a mollic horizon

Umbrihumic

having the organic carbon content as defined above and an umbric horizon.

Hydragric

having an anthraquic horizon and an associated hydragric horizon, the latter occurring within 100 cm from the soil surface (in Anthrosols only).

Hydric

having within 100 cm from the soil surface one or more layers with a total thickness of 35 cm or more, which have a water retention at 1500 kPa (in undried samples) of 100 percent or more (in Andosols only).

Hyperskeletic

having more than 90 percent (by weight) gravel or other coarse fragments to a depth of 75 cm or to continuous hard rock (in Leptosols only).

Irragric

having an irragric horizon; in Anthrosols 50 cm or more thick, in other soils less than 50 cm thick.

Lamellic

having clay illuviation lamellae with a combined thickness of at least 15 cm within 100 cm from the soil surface.

Leptic

having continuous hard rock between 25 and 100 cm from the soil surface.

Endoleptic

having continuous hard rock between 50 and 100 cm from the soil surface.

Epileptic

having continuous hard rock between 25 and 50 cm from the soil surface.

Lithic

having continuous hard rock within 10 cm from the soil surface.

Paralithic

having within 10 cm from the soil surface a broken rock contact with fissures less than 10 cm apart which allow roots to penetrate the underlying rock.

Lixic

having a ferralic horizon which meets the clay increase requirements of an argic horizon, and which has a base saturation (by 1 M NH4OAc) of 50 percent or more throughout the B horizon to a depth of 100 cm from the soil surface (in Ferralsols only).

Luvic

having an argic horizon which has a cation exchange capacity equal to or more than 24 cmolc kg-1 clay throughout, and a base saturation by 1 M NH4OAc) of 50 percent or more throughout the horizon to a depth of 100 cm from the soil surface.

Hypoluvic

having an absolute clay increase of 3 percent or more within 100 cm from the soil surface (in Arenosols only).

Magnesic

having an exchangeable Ca/Mg ratio of less than 1 within 100 cm from the soil surface.

Mazic

having a massive structure and hard to very hard consistence in the upper 20 cm of the soil (in Vertisols only).

Melanic

having a melanic horizon (in Andosols only).

Mesotrophic

having a base saturation (by 1 M NH4OAc) of less than 75 percent at 20 cm depth (in Vertisols only).

Mollic

having a mollic horizon.

Natric

having a natric horizon within 100 cm from the soil surface.

Nitic

having a nitic horizon within 100 cm from the soil surface.

Ochric

having an ochric horizon.

Hyperochric

having an ochric horizon with a light or bleached colour (commonly grey) in dry state which turns darker on moistening ("bleached surface horizons"), a low (usually <0.4%; South African results) organic carbon content and relatively low free iron oxide content, a coarse texture, signs of a platy structure, and a thin surface crust.

Ombric

having a water regime conditioned by groundwater (in Histosols only).

Oxyaquic

saturated with water during the thawing period and lacking redoximorphic features within 100 cm from the soil surface (in Cryosols only).

Pachic

having a mollic or umbric horizon of more than 50 cm thick.

Pellic

having in the upper 30 cm of the soil matrix a Munsell value, moist, of 3.5 or less and a chrome of 1.5 or less (in Vertisols only).

Petric

strongly cemented or indurated within 100 cm from the soil surface.

Endopetric

strongly cemented or indurated between 50 and 100 cm from the surface.

Epipetric

strongly cemented or indurated within 50 cm from the soil surface.

Petrocalcic

having a petrocalcic horizon within 100 cm from the soil surface.

Petroduric

having a petroduric horizon within 100 cm from the soil surface.

Petrogypsic

having a petrogypsic horizon within 100 cm from the soil surface.

Petroplinthic

having a petroplinthic horizon within 100 cm from the soil surface.

Petrosalic

having within 100 cm from the soil surface a horizon 10 cm or more thick which is cemented by salts more soluble than gypsum.

Placic

having within 100 cm from the soil surface a subhorizon of the spodic horizon which is 1 cm or more thick and which is continuously cemented by a combination of organic matter and aluminium, with or without iron ("thin iron pan") (in Podzols only).

Plaggic

having a plaggic horizon; in Anthrosols 50 cm or more thick, in other soils less than 50 cm thick.

Planic

having an eluvial horizon abruptly overlying a slowly permeable horizon within 100 cm from the soil surface.

Plinthic

having a plinthic horizon within 100 cm from the soil surface.

Epiplinthic

having a plinthic horizon within 50 cm from the soil surface.

Hyperplinthic

having a plinthic horizon in which irreversible hardening results in a continuous sheet of ironstone.

Ortihiplinthic

having a plinthic horizon in which irreversible hardening results in a layer of gravel-sized ironstone.

Paraplinthic

having a mottled horizon with at least 10 percent (by volume) iron nodules resembling a plinthic horizon but which does not irreversibly harden on repeated drying and wetting.

Posic

having a zero or positive charge (pHKCl - pHwater) in a layer more than 30 cm thick within 100 cm from the soil surface (in Ferralsols only).

Profondic

having an argic horizon in which the clay distribution is such that the clay content does not decrease by more than 20 percent (relative) from its maximum within 150 cm from the soil surface.

Protic

showing no appreciable soil horizon development (in Arenosols only).

Reductic

having anaerobe conditions caused by gaseous emissions (e.g. methane, carbon dioxide, etc...) (in Anthropic Regosols only).

Regic

lacking recognizable buried horizons (in Anthrosols only).

Rendzic

having a mollic horizon which contains or immediately overlies calcareous materials containing more than 40 percent calcium carbonate equivalent (in Leptosols only).

Rheic

having a water regime conditioned by surface water (in Histosols only).

Rhodic

having a B horizon which has a Munsell hue redder than 5YR (3.5YR or redder) in all parts (apart from minor transitional horizons to A and C horizons), and has a moist colour value of less than 3.5, and a dry colour value no more than one unit higher than the moist value.

Rubic

having a B horizon (or a horizon immediately below the A horizon) with a dominant Munsell colour hue redder than 10YR and/or a moist chrome of 5 or more (in Arenosols only).

Ruptic

having a lithological discontinuity within 100 cm from the soil surface.

Rustic

having a cemented spodic horizon which has enough amorphous iron to turn redder on ignition, which underlies an albic horizon, and lacks a subhorizon of the spodic horizon which is 2.5 cm or more thick and which is continuously cemented by a combination of organic matter and aluminium, with or without iron ("thin iron pan") (in Podzols only).

Salic

having a salic horizon within 100 cm from the soil surface.

Endosalic

having a salic horizon between 50 and 100 cm from the soil surface.

Episalic

having a salic horizon between 25 and 50 cm from the soil surface.

Hyposalic

having an electric conductivity of the saturation extract of more than 4 dS m-1 at 25C in at least some subhorizon within 100 cm from the soil surface.

Hypersalic

having an electric conductivity of the saturation extract of more than 30 dS m-1 at 25 C in at least some subhorizon within 100 cm of the soil surface.

Sapric

having less than one-sixth (by volume) of the organic soil material consisting of recognizable plant tissue (after rubbing) (in Histosols only).

Silic

having an andic horizon with an acid oxalate (pH 3) extractable silica (Siox) content of 0.6 percent or more, or an Alpy/Alox ratio of less than 0.5 in Andosols only).

Siltic

having 40 percent or more silt in a horizon more than 30 cm thick, within 100 cm from the soil surface.

Skeletic

having between 40 and 90 percent (by weight) gravel or other coarse fragments to a depth of 100 cm from the soil surface.

Endoskeletic

having between 40 and 90 percent (by weight) gravel or other coarse fragments between 50 and 100 cm from the soil surface.

Episkeletic

having between 40 and 90 percent (by weight) gravel or other coarse fragments between 20 and 50 cm from the soil surface.

Sodic

having more than 15 percent exchangeable sodium or more than 50 percent exchangeable sodium plus magnesium on the exchange complex within 50 cm from the soil surface.

Endosodic

having more than 15 percent exchangeable sodium or more than 50 percent exchangeable sodium plus magnesium on the exchange complex between 50 and 100 cm from the soil surface.

Hyposodic

having more than 6 percent saturation with exchangeable sodium in at least some subhorizon more than 20 cm thick within 100 cm from the soil surface.

Spodic

having a spodic horizon.

Spolic

having accumulations of anthropogeomorphic soil material containing more than 35 percent (by volume) industrial waste (mine soil, river dredgings, highway constructions, etc.) (in Anthropic Regosols only).

Stagnic

having stagnic properties within 50 cm from the soil surface.

Endostagnic

having stagnic properties between 50 and 100 cm from the soil surface.

Sulphatic

having a soil solution (1:1 in water) with SO4 > > HCO3 > Cl (in Solonchaks only).

Takyric

having a takyric horizon.

Tephric

having tephric soil material to a depth of 30 cm or more from the soil surface.

Terric

having a terric horizon; in Anthrosols 50 cm or more thick, in other soils less than 50 cm thick.

Thionic

having a sulfuric horizon or sulfidic soil material within 100 cm from the soil surface.

Orthithionic

having a sulfuric horizon within 100 cm from the soil surface.

Protothionic

having sulfidic soil material within 100 cm from the soil surface.

Toxic

having within 50 cm from the soil surface concentrations of ions other than aluminium, iron, sodium, calcium or magnesium which are toxic for plant growth.

Turbic

having cryoturbative features (mixed soil material, disrupted soil horizons, involutions (swirl-like patterns in soil horizons), organic intrusions, frost heave, separation of coarse from fine soil materials, cracks, patterned surface features such as earth hummocks, frost mounds, stone circles, nets and polygons), either at the surface or within 100 cm from the soil surface (in Cryosols only).

Umbric

having an umbric horizon.

Urbic

having accumulations of anthropogeomorphic soil material containing more than 35 percent (by volume) earthy materials mixed with building rubble and artifacts (in Anthropic Regosols only).

Vermic

having 50 percent or more (by volume) of wormholes, wormcasts, and filled animal burrows in the upper 100 cm of the soil or down to rock or to a petrocalcic, petroduric, petrogypsic or petroplinthic horizon, whichever is shallower.

Vertic

having a vertic horizon within 100 cm from the soil surface.

Vetic

having less than 6 cmolc kg-1 clay of exchangeable bases plus exchangeable acidity in at least some subhorizon of the B horizon within 100 from the soil surface.

Vitric

having a vitric horizon within 100 cm from the soil surface and lacking an andic horizon overlying a vitric horizon.

Xanthic

having a ferralic horizon with a yellow to pale yellow colour (rubbed soil has Munsell hues of 7.5YR or yellower with a value, moist, of 4 or more and a chrome, moist, of 5 or more).

Yermic

having a yermic horizon including a desert pavement.

Nudiyermic

having a yermic horizon without a desert pavement.

The following prefixes may be used to indicate depth of occurrence, or to express the intensity of soil characteristics or properties. They are combined to one word with other elements, e.g. Orthicalci-. A double combination, e.g. Epihypercalci-, is allowed.

Bathi

horizon, property or material starting between 100 and 200 cm from the soil surface.

Cumuli

having a repetitive accumulation of soil material of 50 cm or more in the surface or A horizon.

Endo

horizon, property or material starting at lower depths, generally between 50 and 100 cm from the soil surface.

Epi

horizon, property or material starting within 50 and 100 cm from the soil surface.

Hyper

having an excessive or strong expression of certain features.

Hypo

having a slight or weak expression of certain features.

Orthi

having a typical expression of certain features (typical in the sense that there is no further or meaningful characterization).

Para

having resemblance to certain features (e.g. Paralithic).

Proto

indicating a precondition or an early stage of development of certain features (e.g. Protothionic).

Thapto

having a buried horizon within 100 cm from the soil surface (given in combination with the buried diagnostic horizon, e.g. Thaptomollic).

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