Thursday, 13 July 2006 - 9:10 AM

Technosols as a Proposed Soil Group for the WRB (World Reference of Soil Resources).

Andreas Lehmann, Hohenheim University (310), D-70593 Stuttgart, Germany

This contribution is the result of discussion within the AKS (Working Group on Urban soils within the German Soil Science Society) and of numerous hints from P. Schad, H.-P. Blume, D. Rossiter, G.-L. Zhang and K. Stahr. Technosols: A new soil group of “Technosols” should be/ is introduced into the WRB (World Reference of Soil Resources). This because of the high meaning of soils with a significant amount of technic material. Such bodies has to be classified as soils as they are places of soil genesis – at least as these soils are settled by pioneer organisms as fungus and bacteria. The high meaning of such soils is given by the large and increasing extent of the areas where they occur. Such areas are urban, industrial, infrastructural, mining and military areas. Additionally, the meaning of Technosols is given by the increasing use of such soils for e.g. urban agriculture. “Technic material” has to be introduced for systematic reasons. Explanations to the definition of technic material and Technosols: Every material should be summarised with Technic material which shows properties that are significant different from natural soil materials, especially as these technic materials are suspicious to toxicity (e.g. combustion residues) and show often very high hydraulic conductivity. The concept behind the term Technosols is the specification of soils with properties conditioned by non-natural substrate and frequently by a cover from natural soil material. These (underlaying) substrates are suspicious for toxic properties and very high hydraulic conductivity. Also, Technosols should be introduced to respect the special problems and benefits of soils from artefacts in points of land use. Moreover, the development of such anthropogenic soils can lead to the formation and discharge of material of unconventional and sometime toxic properties. Sealing material is excluded from technic material, because natural soils or soils from mechanically transported soil material covered by some sealing material should not key out as Technosols. Also soils from soil material which is removed to mine underlying material should not key out as Technosols. The need of not more than 10 cm technic material within 100 cm for a Technosol is proposed especially in respect to the common praxis to cover technic material with natural soil material to allow plant growth and to minimise discharge from the technic material. Also other anthropogenic soils identified with specific qualifiers show often very high hydraulic conductivity.As long as typical sealed or unsealed urban soils (which consist mainly from mechanically transported natural soil material and are showing therefore compaction or loosening, often containing artifacts and much organic residues) can show diagnostic properties of Cambisols, Arenosols, Plinthosols, Durisols, Chernosems, Kastanozems, Phaeozems, Umbrisols and Andosols as well as such soils can show diagnostic properties of Alisols, Acrisols, Luvisols, Lixisols, Nitisols and Solonetz. This, as long as the mechanically transported soil material from the according soils keys out for the relevant diagnostic criteria. Also, disturbed soils can key out to the above given soil groups, if they are not disturbed to the depth that is given as diagnostic criteria. But also in soil groups which have specific processes of soil development as diagnostic criteria, such as Vertisols, Solonchaks, Gleysols and Cryosols, could develop in mechanically transported natural soil – e.g. in some 10 years. Also, large amount of artifacts could be found in Fluvisols if the catchment area includes e.g. cities. It is obvious that Anthrosols and Regosols could consist from mechanically transported natural soil material. Therefore the qualifiers which are proposed as follows should be added to the suggestions for ranking common qualifiers for the 22 mentioned soil groups.

Back to RB Developments in the World Reference Base (WRB), Soil Taxonomy (ST) and Other National Soil Classification Systems for Soil Resources - Oral
Back to WCSS

Back to The 18th World Congress of Soil Science (July 9-15, 2006)