World Reference Base for Soil Resources

The World Reference Base for Soil Resources ( WRB abbreviation ) is a soil classification, which was created as an international means of communication for soil science. It is more or less valid worldwide, to exchange information on soils and their properties across regional and national boundaries.

Origin and background

Since the end of the 19th century in many States in order to describe and classify soils into classes. In the last third of the 20th century, but it became increasingly clear that this development had led to several problems:

  • Due to the independent development of national classifications an international communication problem had arisen. Individual terms appeared in various classifications, but each had different meanings. So the podsolization in Germany stands for the relocation of sesquioxides and humus. But in Russia, it also includes the relocation of clay. In addition, there were a variety of names for the same soil.
  • National systems have been adapted in their creation to the circumstances of each country. So it was that although they are highly specific to their areas of origin; Soils in other areas but hardly treat. In most classification missing even whole topics. As an example, the internationally important soil types of frost or saline soils may be mentioned here that do not occur in the German soil classification. No system was then able to treat all floors of the World satisfactory.
  • Although each system had weaknesses and was not suitable for use worldwide, reported on all but large, not abweisbare strengths. Since they were perfectly adapted to the country-specific soils, they contained an enormous attention to detail. If they had simply been abolished, so a loss of data and descriptive possibilities would have been inevitable. Soils are complex phenomena that a user- friendly classification held for worldwide use can not achieve the accuracy of national systems.
  • There were also national interests, since no country was willing to just give up his accumulated over decades and taught at all educational classification.

The U.S. began to radically transform their classification to cover the world with her all floors. The resulting Soil Taxonomy was not accepted internationally, despite strong efforts by the United States.

Instead, one of the Food and Agriculture Organization ( FAO) sat through elaborate system; the FAO soil classification ( "Soil Map of the World"), released in 1988. At its drafting had with numerous countries, including Germany, in a long-term process. The FAO was the initiator of the international soil understanding, since the exchange of soil information was required primarily for agricultural purposes.

Was published in 1998 at the 16th World Congress of Soil Science from then on as the WRB (World Reference Base ) designated classification as a successor to the older version of FAO. In the same year the ISSS (International Society of Soil Science) put it firmly as an international classification. Since the summer of 2006 is a new, strongly revised version of the WRB before, in the suggestions from nearly 10 years of practice experience were incorporated, and in 2007 a ​​revised version was published. From the version from 2006 also exists for the first time an official German -language translation.

A special feature of the WRB is that they should not replace national classifications. It represents an international language for global clearly publish findings in soil science and share more easily. This is also evident from the name, because WRB stands for World Reference Base or German: world reference base.

The WRB is also recognized in Germany, although it is primarily used the German soil classification and taught at universities. In German-speaking literature sometimes the WRB designations given parallel to those of the German Soil Classification. A unique translatability of German soil designations in the WRB is not possible.

Floor speech by WRB

The names used for the soil types are mainly art names that have their roots in Latin, the Greek language, as well as among modern languages ​​, especially in Russian.

The classification is divided into two levels:

At the first level, reference soil groups ( reference soil groups - RSG ) distinguished, of which there are ( 1998: 30) 32. The classification of a soil in each RSG is based on a key, in which, in a defined sequence for the presence and the depth of diagnostic horizons (diagnostic horizons ), diagnostic characteristics (diagnostic properties ) or diagnostic materials (diagnostic materials) is required. The classification into a RSG performed based on the first complete set of criteria fulfilled.

In the second level, the qualifiers are ( the German translation features is uncommon) that differentiate the reference soil group on. A total of 163 different qualifier (as well as 54 pre-defined compositions of qualifiers with specifiers ) are available. Here are three possible types of qualifiers:

Typically associated and transition qualifiers are provided as prefixes in front of the name of the RSG, other qualifier in parentheses as suffixes beyond. The names of the Qulaifier be capitalized.

For each RSG there is a list of allowable qualifiers, with an RSG minimum 9 and maximum 30 possible characteristics are assigned. Of the possible quality remote must be selected all that apply. ( On behalf of the RSG ie closer ) it is higher up in the list of possible prefix qualifier is the more right. Following the same principle ( position relative to the name of the RSG ) are suffix qualifiers specified in the order in which they appear in the list. For purposes of creating map legends, the number of qualifiers can be reduced. Does no other prefix qualifier to the list, the soil receives the prefix qualifier Haplic ( " usually ").

The qualifier can be modified with the help of specifiers in her statement, for example, if a qualifier applies only to a portion of the soil profile. The specifier can be hung as a prefix (s) to the appropriate qualifier.

Due to the practically non-hierarchical classification, it is possible to address several thousand different soil subunits.

If the current WRB compared to the legend of the old FAO World Soil Map, it is noticeable that the statement about the potential uses and use restrictions has disappeared entirely from the WRB. The former Soil Phases, ie the state in which there are the floors are, although having entered the differentiating features of the WRB, but they are no longer recognizable.

List of reference soil groups

The list of reference soil groups comprises 32 floors that are not in alphabetical order but in the order of the WRB key for soil description with details of the code:

Organic soils

  • HS Histosol (soils, which consist mainly of organic material )

Anthropogenic soils

  • AT anthrosol (soils, their properties were significantly influenced by human activities )
  • TC Technosol

Soils with restricted rooting

  • CR CryoSol (soils that have a region of permafrost within one meter )
  • LP Leptosol (soils that are very shallow and are located above bedrock )

Water Affected soils

  • VR Vertisol (soils, which, due to swelling and shrinking clay minerals an inner movement of material, are incorporated by, inter alia, dark humic substances )
  • FL Fluvisol ( relatively poorly developed soils from young river, lake or marine sediment )
  • SN solonietz ( soils that are tonangereichert underground and high concentrations of sodium have )
  • SC Solonchak ( soils that are very salty )
  • GL Gleysol ( soils that are permanently or temporarily marked up at or near the surface of redox processes primarily through groundwater saturation)

By iron and / or aluminum processes embossed flooring

  • AN Andosol (soils that are young and often originated from volcanic deposits )
  • PZ podzol (soils that are acidic and have underground accumulations of iron-aluminum - organic compounds)
  • PT Plinthosol (floors that harden in an irreversible dehydration of iron compound, clay and quartz)
  • NT Nitisol (soils, which are deep and have brown or yellow color and distinctive shiny Agregatflächen )
  • FR Ferralsol ( soils that are triefgründig weathered and low in nutrients, but have a stable physical structure)

Backwater soils

  • PL Planosol (soils, which have a bleached horizon by temporary accumulation of water to near the ground surface over a low water-conducting horizon a geologically another layer with a significantly higher clay content )
  • ST Stagnosol (soils, which have a bleached horizon by temporary accumulation of water to near the ground surface over a low water-conducting horizon in the same geological layer)

Humus accumulation soils

  • CH Chernozem (soils that have a deep, dark, humus-rich, nutrient-rich, lime or gypsum-bearing topsoil )
  • KS Kastanozem ( soils, which have a brown, humus-rich, lime or gypsum-bearing topsoil )
  • PH Phaeozem ( soils, which have a brown, humus-rich, lime or gypsum-free, well -supplied nutrient topsoil )

Salt accumulation soils

  • GY Gypsisol
  • DU Durisol
  • CL Calcisol (soils with the profile shifted, again precipitated carbonate )

Soils with Tonverlagerungshorizonten

  • AB Albeluvisol (soils with tongue-shaped teeth of Tonauswaschungs and Toneinwaschungshorizont )
  • AL Alisol ( soils with a Toneinwaschungshorizont with high cation exchange capacity and low base saturation )
  • AC Acrisol ( soils with a Toneinwaschungshorizont with low cation exchange capacity and low base saturation )
  • LV Luvisol ( soils with a Toneinwaschungshorizont with high cation exchange capacity and high base saturation )
  • LX LIXISOL ( soils with a Toneinwaschungshorizont with low cation exchange capacity and high base saturation )

Young, poorly differentiated soils

  • UM Umbrisol ( soils that have a dark, humus-rich, nutrient-poor topsoil )
  • AR Arenosol ( sandy soils )
  • CM Cambisol ( soils with a verbraunten or verlehmten or otherwise altered horizon have )
  • RG regosol

Procedure example

Using an example, the procedure for soil description with the WRB should be shown:

Level 1: Definition of the reference soil group

Result: The key diagnostic for the RSG Leptosol true. All later in the list following RSG are no longer in question. The reference soil group is Leptosols.

Level 2: Determination of the qualifier

For the Leptosol 17 prefixes come into question. The exact qualifier list and the meaning of each qualifier can the WRB be removed (see links). In this case, the soil should consist of moderately weathered volcanic deposits ( Andic ) and extremely shallow be ( Lithic ). All other possible prefixes do not apply. Lithic in the list before Andic and therefore must be closer to the name of the reference soil group. So are the prefixes Andic Lithic.

In addition, 19 possible suffixes are in the list, one of which applies only the relatively good nutrient ( Eutric ). Thus, there is in this soil the suffix Eutric.

The soil is, therefore: Andic Lithic Leptosol ( Eutric )

If there were more suffixes, these would be listed separated by commas in the trailing parenthesis, and in the order as they appear in the list of possible qualifiers.

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