Inspire revision 4711
Gyldig
-- Name --
FAO horizon notation type
A classification of a horizon according to the Horizon classification system specified in Guidelines for soil description, 4th edition, Food and Agriculture Organization of the United Nations, Rome, 2006.
-- Description --
A code system that denotes horizons in which the same dominant soil forming processes has been active similarly. This code summarizes many observations of the soil description and gives an impression about the genetic processes that have formed the soil under observation.
NOTE The horizon notation according to FAO (2006) is a combination of several symbols:
· A number that gives information about discontinuities, i.e. the number of the material in which the soil has formed, counted up from the soil surface, but not for the first material.
· One or two capital letters that designate the type of master horizon (or transitional horizon), possibly separated by a slash
· Lower case letters that designate subordinate characteristics of the horizon.
· A number that designates horizontal subdivisions of otherwise similarly denoted horizon parts
· A prime that enables to distinguish two horizons that have the same naming, but formed in different cycles of pedogenesis.
EXAMPLE 2B' tg1
SOURCE 1 Page 67 - 77 of the Guidelines for soil description, 4th edition, Food and Agriculture Organization of the United Nations, Rome, 2006. (ISBN 92-5-105521-1)
| Egenskap |
Stereotype |
Beskrivelse |
Type |
Multiplisitet |
| FAOHorizonDiscontinuity |
|
-- Name --
FAO horizon discontinuity
|
Integer |
0..1 |
| FAOHorizonMaster |
|
-- Name --
FAO horizon master
|
FAOHorizonMasterValue
(kodeliste)
|
1..1 |
| FAOPrime |
|
-- Name --
FAO prime
|
FAOPrimeValue
(kodeliste)
|
1..1 |
| FAOHorizonSubordinate |
|
-- Name --
horizon subordinate
|
FAOHorizonSubordinateValue
(kodeliste)
|
0..* |
| FAOHorizonVertical |
|
-- Name --
horizon vertical
|
Integer |
0..1 |
| isOriginalClassification |
|
-- Name --
is original classification
|
Boolean |
1..1 |
| Name |
Type |
English |
Description |
| FAOHorizonDiscontinuity |
Integer |
|
number used to indicate a discontinuity in the horizon notation.
-- Description --
In mineral soils, Arabic numerals are used as prefixes to indicate discontinuities. Wherever needed, they are used preceding A, E, B, C and R. They are not used with I and W, although these symbols clearly indicate a discontinuity. These prefixes are distinct from Arabic numerals used as suffixes to denote vertical subdivisions.
A discontinuity is a significant change in particle-size distribution or mineralogy that indicates a difference in the material from which the horizons formed or a significant difference in age or both, unless that difference in age is indicated by the suffix b. Symbols to identify discontinuities are used only when they will contribute substantially to the reader’s understanding of relationships among horizons. The stratification common in soils formed in alluvium is not designated as discontinuities unless particle-size distribution differs markedly from layer to layer even though genetic horizons have formed in the contrasting layers.
Where a soil has formed entirely in one kind of material, a prefix is omitted from the symbol; the whole profile is material 1. Similarly, the uppermost material in a profile having two or more contrasting materials is understood to be material 1, but the number is omitted. Numbering starts with the second layer of contrasting material, which is designated 2. Underlying contrasting layers are numbered consecutively.
SOURCE: <i>Guidelines for soil description, 4th edition</i>, Food and Agriculture Organization of the United Nations, Rome, 2006.
NOTE a discontinuity is a boundary between two geogenic layers. |
| FAOHorizonMaster |
FAOHorizonMasterValue
|
|
symbol of the master part of the horizon notation.
-- Description --
SOURCE Guidelines for soil description (4th ed.) FAO 2006 p. 67
|
| FAOPrime |
FAOPrimeValue
|
|
A prime and double prime may be used to connotate master horizon symbol of the lower of two respectively three horizons having identical Arabic-numeral prefixes and letter combinations.
-- Description --
Identical designations may be appropriate for two or more horizons or layers separated by at least one horizon or layer of a different kind in the same pedon. The sequence A-E-Bt-E-Btx-C is an example - the soil has two E horizons. To make communication easier, a prime is used with the master horizon symbol of the lower of two horizons having identical letter designations: A-E-Bt-E’-Btx-C.The prime is applied to the capital letter designation, and any lower case symbol follows it: B’t. The prime is not used unless all letters of the designations of two different layers are identical. Prime can be used for both minerals or organic soils.
SOURCE: <i>Guidelines for soil description, 4th edition</i>, Food and Agriculture Organization of the United Nations, Rome, 2006. |
| FAOHorizonSubordinate |
FAOHorizonSubordinateValue
|
|
Designations of subordinate distinctions and features within the master horizons and layers are based on profile characteristics observable in the field and are applied during the description of the soil at the site.
-- Description --
Lower case letters are used as suffixes to designate specific kinds of master horizons and layers, and other features.
SOURCE <i>Guidelines for soil description, 4th edition</i>, Food and Agriculture Organization of the United Nations, Rome, 2006. table 85 |
| FAOHorizonVertical |
Integer |
|
Order number of the vertical subdivision in the horizon notation.
-- Description --
The number is used to designate the horizontal subdivision of a horizon identified by a single set of letter symbol on the basis of structure, texture, colour, etc.
The number 1 is used to designate the upper part of the horizon. The number 2 the part of the horizon situated below, etc. If there is no horizontal subdivision made, no number is given.
NOTE the use of the word vertical is misleading in the <i>Guidelines for soil description, 4th edition</i>, Food and Agriculture Organization of the United Nations, Rome, 2006., because the horizons are separated in two or several horizontal subdomains. Vertical denotes the order in vertical direction. |
| isOriginalClassification |
Boolean |
|
Boolean value to indicate whether the FAO horizon notation was the original notation to describe the horizon.
-- Description --
This is to indicate whether the horizon notation has been determined in the field (or for derived profiles during the original derivation), or has been adapted, changed or assigned on the basis of the original horizon description later. This might be relevant data quality information.
|