EUROPEAN BUREAU  RESEARCH REPORT NO. 7

Classification of , and in Austria according to the World Reference Base for Soil Resources (WRB)

NESTROY Othmar Institute of Engineering Geology and Applied Mineralogy, Graz University of Technology, Rechbauerstrasse 12, A-8010 Graz, Austria.

Austria and the occurrence of Austria has an area of about 84.000 km2. In the NE-part there are numerous occurrences of steppe soils. There are two reasons for these soil types: calcareous (the parent material), and specific climatic conditions, like temperature and rainfall. The consequence is a twice-yearly interruption of soil development (the summer drought and the winter freezing) which results in inhibited weathering without a B horizon. These soils are normally calcareous including the A horizon(s) and are grouped in the Chernozems, but in comparison with these soils in Russia there are differences in the content of and calcium carbonate.

Steppe soils in the Austrian , 2000 In the Pannonian region the mean annual temperature is 9.5 to 10ºC and annual rainfall is between 400 and 600 mm (O. Harlfinger and G. Knees, 1999). Soils have these physical and chemical characteristics: texture is dominated by a high content (about more than 50%) of (2-60 (m), aggregates are crumb (in the topsoil) and medium subangular blocky with an optimal distribution of middle pores (high water holding capacity), colours are about 10 YR 3/3 or browner, content of humus is about 2 %, and the content of calcium carbonate is high (about 10 %), even in the topsoil.

In the Austrian Soil Classification 2000 (O. Nestroy, 2000) there are 2 orders (terrestrial and hydromorphic soils), 13 classes, 46 types and 70 subtypes. The number of varieties is unlimited. In the order of terrestrial soils and in the class of raw humus and developed A-C-soils (Auflagehumusböden und Entwickelte A-C- Böden) there are (Tschernosem) and Trunk-Chernozem (Rumpf-Tschernosem) types. In the Chernozem (ST) type, there is the subtype Calcareous ST with the varieties gleyic, non calcareous in the topsoil, brownish, the Calcareous Brown ST subtype with varieties of gleyic and decalcified in the topsoil, and the Non Calcareous ST subtype with the gleyic variety. The Trunk-Chernozem (SR) type has Non Calcareous SR and Calcareous SR subtypes with gleyic and brownish varieties.The types and subtypes of the Wet-Chernozems (Feuchtschwrzerden) will not be discussed here.

The first example of a new classification of the Chernozems is given by the WRB-Draft from 1994. There is the climatic (bio-)sequence of loess soils in Eastern Europe after A.Bronger (1993) from Grey Brown Podzolic soil (Dernopodsol) under mixed forest to Phaeozems (Dark Gray Forest soil and Podzolized Leached and more or less Degraded soils) under deciduous forest and forest steppe with a deep Ah horizon and a B horizon without calcium carbonate. There are three types of Chernozems (Typical Deep, Ordinary and Southern) with decreasing depth and decreasing content of organic matter, only with one Ah horizon, without a B horizon and the boundary of lime content from about 80 cm to between 50 and 40 cm in depth. Also there are krotovinas and bieloglaskas and pseudomycelia. The vegetation is a transition from the tallgrass to midgrass steppe. Finally there are the Dark and Light Katanozemtypes (after the Russian classification: Chestnuts) under a short grass steppe with a low content of humus in the topsoil, with krotovinas, bieloglaskas and pseudomycelia and a lime content in the first 25 cm.

Chernozems, Phaeozems and Calcisols in Austria according to WRB. Nestroy. 121 EUROPEAN SOIL BUREAU  RESEARCH REPORT NO. 7

Figure 1. The climatic (bio-)sequence of loess soils in Eastern Europe (after A. Bronger, In:WRB Draft , 1994)

The second example for the classifcation is taken from the book by G. Hintermaier-Erhard and W. Zech (1997). According to Gerasimov and Glazovskaja (1960) the Phaeozems occur under forest steppe with 500-650 mm annual rainfall, 5-7 (C mean annual temperature, have a high content of humus (more than 11%) and humus horizons until 80 cm depth, and the first 100 cm are free of carbonates and gypsum. Under tallgrass steppe with 300-600 m annual rainfall and 6-10 (C mean annual temperature the Chernozems occur. The content of humus is high like by the Phaeozems, but deeper (until about 120 cm) and carbonates occur from the depth of 80 cm. The are under short grass steppe with 250-350 mm annual rainfall and 5-9 (C mean annual temperature. This type has only 6% humus in the topsoil and the humus reached only 80 cm, but from 40 cm depth thee are carbonates and occasionally below 1 m there is gypsum (Figure2.).

The third approach is given in the following comparison with Chernozems, Kastanozems, Phaeozems and Calcisols according to the WRB 1998. Chernozems: 1. A mollic horizon with a moist chroma of 2 or less if the texture is finer than sandy , or less than 3.5 if the texture is sandy loam or coarser, both to a depth of at least 20 cm, or having these chromas directly below any plough layer; and 2. Concentration of secondary carbonates starting within 50 cm of the lower limit of the Ah horizon but within 200 cm from the soil surface; and 3. No petrocalcic horizon between 25 and 100 cm from the soil surface; and 4. No secondary gypsum; and 5. No uncoated silt and grains on structural ped surfaces. Kastanozems: 1. A mollic horizon with a moist chroma of more than 2 to a depth of at least 20 cm, or having this chroma directly below any plough layer; and 2. Concentration of secondary carbonates within 100 cm from the soil surface; and 3. No diagnostic horizon other than an argic, calcic, cambic, gypsic or vertic horizon.

122 Chernozems, Phaeozems and Calcisols in Austria according to WRB. Nestroy. EUROPEAN SOIL BUREAU  RESEARCH REPORT NO. 7

Phaeozems: 1. A mollic horizon; and 2. A base saturation (by 1 m NH4OAC) of 50 percent or more and a calcium carbonate-free soil matrix at least to a depth of 100 cm from the soil surface, or to a contrasting layer (lithic or paralithic contact, petrocalcic horizon) between 25 and 100 cm; and 3. No diagnostic horizon other than an albic, argic, cambic or vertic horizon, or a petrocalcic horizon in the substratum. Calcisols: 1. A calcic or petrocalcic horizon within 100 cm of the surface; and 2. No diagnostic horizons other than an ochric or cambic horizon; an argic horizon, which is calcareous, a vertic horizon, or a gypsic horizon underlying a petrocalcic horizon.

Figure 2. Distribution of humus, calcium carbonate and gypsum in Steppe Soils of Central Asia

Classification of the Austrian steppe soils according to WRB 1998 We realized that the Austrian Chernozems do not readily fit with the criteria for Chernozems, Kastanozems, Phaeozems and Calcisols in the present frame. The obstacles for a clear decision include: soils not dark enough , the content of humus in the topsoil is too low and the high content of calcium carbonate from the surface until the bottom make problems for correlation with the WRB proposals.

Nevertheless the following comparisons are suggested: 1. The Austrian Calcareous dark Chernozem can be compared with the mollic, calcic Chernozem after WRB, possibly with chernic, calcic Chernozem. The Calcareous light Chernozems can be compared with the mollic, calcic . 2. The Austrian Calcareous brown Chernozem can be compared with the mollic, calcic Kastanozem after WRB, and the non calcareous Chernozem with the mollic, haplic Kastanozem.

Chernozems, Phaeozems and Calcisols in Austria according to WRB. Nestroy. 123 EUROPEAN SOIL BUREAU  RESEARCH REPORT NO. 7

To compare the Austrian non calcareous and calcareous Trunk-Chernozem with the WRB is also not problem-free. An expression for eroded types and profiles is missing in the actual framework, therefore we can only put these two types into haplic Chernozems or haplic Kastanozems respectively, or possibly as haplic, calcic Chernozems or haplic, calcic Kastanozems. According to WRB a has "... a calcium carbonate-free soil matrix at least to a depth of 100 cm from the soil surface...". A is characterized by "... a calcic or petrocalcic horizon within 100 cm of the surface; and no diagnostic horizons other than an ochric or cambic horizon, an argic horizon which is calcareous, a vertic horizon, or a gypsic horizon underlying a petrocalcic horizon." In my opinion the features of the Austrian steppe soils are not adequate for assignment to either the Phaeozems or Calcisols.

Outlook "The WRB is not a complete classification system, but only, and this is essential, a basis, a framework, for better correlation between national systems of soil classification. We also hope that the WRB will help national systems to continue their elaboration. This first edition is not a final one. It has to be used, discussed, criticized, completed and updated. It has to be transformed in conjunction with the advances in " (A. Ruellan, 1998).

And J.A. Deckers et al. (1998) set out: "The WRB is designed as an easy means of communication among scientists to identify, characterize and name major types of soil. It is not meant to replace national soil classification systems but will serve as a common denominator through which national systems can be compared and correlated. WRB also serves as a common ground between people with an interest in land- and natural resources."

In the sense of O. Spaargaren (1998) future WRB activities are inter alia: continued field-testing; further elaboration of the qualifiers; and compilation of a handbook on field methods.

In Austria, we have enough physical and chemical data from soil profiles; we have the distribution of these types and subtypes; and we know the yields for a long time. Last but not least, we have actual data from the Austrian Agricultural and Forest Soil Monitoring program, thus future discussion is important and can go forward on a solid basis.

References Deckers, J., O.C. Spaargaren and F.O. Nachtergaele (1998): World Reference Base for Soil Resources. An Introduction. Intern. Society of Soil Science, ISSS Working Group RB, Leuven. Food and Agriculture Organization of the United Nations (Ed.)(1998): World Reference Base for Soil Resources. Soil Publ. 84, Rome. Harlfinger, O. und G. Knees (1999): Klimahandbuch der Österreichischen Bodenschätzung. Mitt. d. Österr. Bodenkundl. Ges., H. 58, Wien. Hintermaier-Erhard, G. und W. Zech (1997): Wörterbuch der Bodenkunde. Ferd. Enke Verlag, Stuttgart. Nestroy, O. et al. (2000): Österreichische Bodensystematik 2000. Mitt. d. Österr. Bodenkundl. Ges., H. 60, Wien. Ruellan, A. (1998): Preface. World Reference Base for Soil Resources. An Introduction. Intern. Society of Soil Science, ISSS Working Group RB, Leuven. Spaargaren, O.C. (Ed.)(1994): World Reference Base for Soil Resources. Draft. Wageningen/Rome. Spaargaren, O.C. (1998): Bulletin of the International Union of Soil Science, No. 94, Vienna.

124 Chernozems, Phaeozems and Calcisols in Austria according to WRB. Nestroy.