Definitions of formative elements for lower level units(cont. a)

Explanatory notes to the use and definition of a number of lower-level names

Related to diagnostic horizons. Most of the diagnostic horizons can be considered for naming soil subunits with the following exceptions or clarifications.

Argic horizon. The name Luvic at the lower level to indicate the occurrence of an argic horizon, rather than Argic. In Arenosols the term Hypoluvic is used for the intergrade with Luvisols, although no argic horizon is present.

Cambic horizon. The use of the soil subunit name Cambic is in general not recommended.

Ferralic horizon. The name Ferralic is not used to indicate the presence of a ferralic horizon, as this would be confusing with the meaning of the diagnostic property and soil unit connotative "ferralic". However, it is used to separate soil subunits having ferralic properties within 100 cm (e.g. Hypoferralic).

Sulfuric horizon. The use of the soil subunit name Sulfuric is not recommended. Instead of Sulfuri-Thionic, Orthi-Thionic should be used.

Related to diagnostic properties and soil materials. Most of the diagnostic criteria can be used without changing the definition or corresponding connotative of the lower level subdivision. However, the following remarks have to be made.

Colour. Soil colour of the B horizon can be indicated to a varying degree using the terms Rhodic, Rubic, Chromic and Xanthic. Preferably these terms should be limited to soils having an argic or ferralic horizon, or applied in Cambisols and Arenosols. In Vertisols the term Pellic is used to indicate dark coloured soils.

Dystric/eutric. According to the rules for the definitions of soil subunit names, Dystric and Eutric have unique meanings, but they should not be used to further specify soils which are clearly acid (e.g. no Dystri-Orthithionic Fluvisol) or basic (e.g. no Eutri-Petric Calcisol).

Fluvic soil materials. The soil subunit name Fluvic may be significant for the reference soil groups of Gleysols and Cambisols, to indicate the presence of fluvic properties. Thin surface mantles of new material (less than 50 cm thick) should be recorded as a phase.

Sodic properties. The soil subunit name Sodic can be used indicating an exchangeable sodium percentage (ESP) of more than 15 within 50 cm from the soil surface. An ESP higher than 6 can be indicated by the term Hyposodic.

Sulfidic soil materials. The term sulfidic soil materials is used together with the diagnostic sulfuric horizon to separate Thionic soil units. If a subdivision of Thionic soil units is required, it is suggested to use the prefix Proto for soils with sulfic soil materials only. It is not recommended to use the name Sulfic or Sulfidic to subdivide Thionic soil units.

Tonguing. Provision is made for two types of tonguing: one being tonguing of an albic horizon into a B horizon (Albiglossic), the other being the more unusual case of tonguing of an A horizon into the B or C horizon (Glossic, Molliglossic and Umbriglossic).

Priority sequence for the reference soil groups

The priority sequences for the reference soil groups are listed in Table 4. It should be emphasized that the priority sequence for a given reference soil group takes into account the possible connotative combinations for all soil units pertaining to that reference soil group, but not all items in the sequence are necessarily applicable to every individual soil unit defined within the group, because definitions and general rules of the system preclude the occurrence of certain combinations.

TABLE 4: Priority listing of lower-level units of reference soil groups

HISTOSOLS	CRYOSOLS	ANTHROSOLS	LEPTOSOLS	VERTISOLS
Cryic	Histic	Hydragric	Lithic	Thionic
Glacic	Lithic	Irragric	Gleyic	Salic
Salic	Leptic	Terric	Rendzic	Natric
Gelic	Turbic	Plaggic	Umbric	Gypsic
Thionic	Salic	Hortic	Yermic	Duric
Folic	Natric	Gleyic	Aricic	Calcic
Fibric	Gleyic	Stagnic	Vertic	Alic
Sapric	Andic	Spodic	Gelic	Gypsiric
Ombric	Mollic	Ferralic	Hyperskeletic	Pellic
Rheic	Gypsic	Luvic	Mollic	Grumic
Alcalic	Calcic	Arenic	Humic	Mazic
Toxic	Umbric	Regic	Gypsiric	Chromic
Dystric	Yermic		Calcaric	Mesotrophic
Eutric	Aridic		Dystric	Hyposodic
	Glacic		Eutric	Eutric
	Thionic		Haplic	Haplic
	Oxyaquic
	Stagnic
	Haplic
FLUVISOLS	SOLONCHAKS	GLEYSOLS	ANDOSOLS	PODZOLS
Histic	Histic	Histic	Vitric	Gelic
Thionic	Vertic	Thionic	Eutrisilic	Gleyic
Salic	Gleyic	Anthraquic	Silic	Stagnic
Gleyic	Sodic	Endosalic	Gleyic	Densic
Mollic	Mollic	Andic	Melanic	Carbic
Umbric	Gypsic	Vitric	Fulvic	Rustic
Arenic	Duric	Plinthic	Hydric	Histic
Takyric	Calcic	Sodic	Pachic	Umbric
Yermic	Petrosalic	Mollic	Histic	Entic
Aridic	Takyric	Gypsic	Mollic	Placic
Gelic	Yermic	Calcic	Duric	Skeletic
Stagnic	Aridic	Umbric	Umbric	Fragic
Humic	Gelic	Arenic	Luvic	Lamellic
Gypsiric	Stagnic	Takyric	Placic	Anthric
Calcaric	Hypersalic	Gelic	Leptic	Haplic
Sodic	Ochric	Humic	Acroxic
Tephric	Aceric	Alcalic	Vetic
Skeletic	Chloridic	Alumic	Calcaric
Dystric	Sulphatic	Toxic	Arenic
Eutric	Carbonatic	Abruptic	Sodic
Haplic	Haplic	Calcaric	Skeletic
		Tephric	Thaptic
		Dystric	Dystric
		Eutric	Eutric
		Haplic	Haplic
PLINTHOSOLS	FERRALSOLS	SOLONETZ	PLANOSOLS	CHERNOZEMS
Petric	Plinthic	Vertic	Histic	Chernic
Alic	Gleyic	Gleyic	Vertic	Vertic
Acric	Andic	Salic	Thionic	Gleyic
Umbric	Acric	Mollic	Endosalic	Luvic
Albic	Lixic	Gypsic	Plinthic	Glossic
Stagnic	Arenic	Duric	Gleyic	Calcic
Endoeutric	Gibbsic	Calcic	Sodic	Siltic
Geric	Geric	Magnesic	Mollic	Vermic
Humic	Humic	Takyric	Gypsic	Haplic
Endoduric	Histic	Yermic	Calcic
Vetic	Mollic	Aridic	Alic
Alumic	Umbric	Stagnic	Luvic
Abruptic	Endostagnic	Albic	Umbric
Pachic	Vetic	Humic	Arenic
Glossic	Posic	Haplic	Gelic
Ferric	Alumic		Albic
Haplic	Ferric		Geric
	Hyperdystric		Petroferric
	Hypereutric		Alcalic
	Rhodic		Alumic
	Xanthic		Ferric
	Haplic		Calcaric
			Rhodic
			Chromic
			Dystric
			Eutric
			Haplic
KASTANOZEMS	PHAEOZEMS	GYPSISOLS	DURISOLS	CALCISOLS
Vertic	Leptic	Petric	Petric	Petric
Gypsic	Vertic	Leptic	Leptic	Leptic
Calcic	Gleyic	Vertic	Vertic	Vertic
Luvic	Andic	Endosalic	Gypsic	Endosalic
Hyposodic	Vitric	Sodic	Calcic	Gleyic
Siltic	Sodic	Duric	Luvic	Sodic
Chromic	Luvic	Calcic	Arenic	Luvic
Anthric	Albic	Luvic	Takyric	Takyric
Haplic	Stagnic	Takyric	Yermic	Yermic
	Greyic	Yermic	Aridic	Aridic
	Pachic	Aridic	Chromic	Skeletic
	Abruptic	Arzic	Hyperochric	Hyperochric
	Glossic	Skeletic	Haplic	Hypercalcic
	Tephric	Hyperochric		Hypocalcic
	Calcaric	Hypergypsic		Haplic
	Skeletic	Hypogyspic
	Siltic	Haplic
	Vermic
	Chromic
	Haplic
ALBELUVISOLS	ALISOLS	NITISOLS	ACRISOLS	LUVISOLS
Histic	Vertic	Andic	Leptic	Leptic
Gelic	Plinthic	Mollic	Plinthic	Vertic
Gleyic	Gleyic	Alic	Gleyic	Gleyic
Alic	Andic	Umbric	Andic	Andic
Umbric	Nitic	Humic	Vitric	Vitric
Arenic	Umbric	Vetic	Umbric	Calcic
Fragic	Arenic	Alumic	Arenic	Arenic
Stagnic	Stagnic	Rhodic	Stagnic	Stagnic
Alumic	Albic	Ferralic	Geric	Albic
Endoeutric	Humic	Dystric	Albic	Hyposodic
Abruptic	Abruptic	Eutric	Humic	Profondic
Ferric	Profondic	Haplic	Vetic	Lamellic
Siltic	Lamellic		Abruptic	Ferric
Haplic	Ferric		Profondic	Rhodic
	Hyperdystric		Lamellic	Chromic
	Skeletic		Ferric	Cutanic
	Rhodic		Alumic	Hyperochric
	Chromic		Hyperdystric	Dystric
	Haplic		Skeletic	Haplic
			Rhodic
			Chromic
			Hyperochric
			Haplic
LIXISOLS	UMBRISOLS	CAMBISOLS	ARENOSOLS	REGOSOLS
Leptic	Gelic	Gelic	Gelic	Gelic
Plinthic	Leptic	Leptic	Plinthic	Leptic
Gleyic	Gleyic	Vertic	Gleyic	Gleyic
Andic	Arenic	Fluvic	Hypoluvic	Thaptoandic
Vitric	Stagnic	Endosalic	Yermic	Thaptovitric
Calcic	Albic	Plinthic	Aridic	Arenic
Arenic	Humic	Gelistagnic	Ferralic	Takyric
Stagnic	Ferralic	Stagnic	Albic	Yermic
Geric	Skeletic	Gleyic	Gypsiric	Aridic
Albic	Anthric	Andic	Calcaric	Gelistagnic
Humic	Haplic	Vitric	Lamellic	Stagnic
Vetic		Mollic	Rubic	Anthropic
Abruptic		Takyric	Fragic	Aric
Profondic		Yermic	Hyposalic	Garbic
Lamellic		Aridic	Tephric	Reductic
Ferric		Sodic	Hypoduric	Spolic
Rhodic		Ferralic	Protic	Urbic
Chromic		Gypsiric	Dystric	Humic
Hyperochric		Calcaric	Eutric	Vermic
Haplic		Skeletic	Haplic	Hyposalic
		Rhodic		Hyposodic
		Chromic		Gypsiric
		Hyperochric		Calcaric
		Dystric		Tephric
		Eutric		Skeletic
		Haplic		Hyperochric
				Dystric
				Eutric
				Haplic

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