ANTHROSOLS (And TECHNOSOLS)
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ANTHROSOLS (and TECHNOSOLS) Otto Spaargaren ISRIC – World Soil Information Wageningen The Netherlands Definition of Anthrosols Anthrosols: soils that have been formed or profoundly modified through long- term human activities, such as addition of organic materials or household wastes, irrigation or cultivation. Diagnostics of Anthrosols Anthrosols have one of the following: z A hortic horizon z An irragric horizon z A plaggic horizon z A terric horizon, or z An anthraquic with underlying hydragric horizon, all 50cm or more thick Hortic horizon Results from deep cultivation, intensive fertilisation and/or long-term application of organic wastes: z Munsell value and chroma 3 or less z Average organic C 1 percent or more -1 z P2O5 > 100 mg kg in upper 25cm z Base saturation 50 percent or more Irragric horizon Results from long-term irrigation with sediment-rich water: z Munsell value and chroma more than 3 z Uniform structure z Average organic C > 0.5 percent, and remaining > 0.3 percent at its lower limit z Even distribution of carbonates and clay z Higher clay content than underlying soil Terric horizon Results from long-term addition of earthy manure, compost or mud: z Non-uniform texture z Colour depending on source material z Base saturation 50 percent or more Plaggic horizon Results from long-term addition of sods mixed with farmyard manure: z Uniform texture (sand or loamy sand) z Average organic C > 0.6 percent -1 z P2O5 > 250 mg kg in upper 20cm z Base saturation < 50 percent Anthraquic horizon Results from long-term wet cultivation and includes a puddled layer and a plough pan: z Platy structure in plough pan z Rust mottles along cracks and root holes z Bulk density of plough pan 20 percent or more compared to that of puddled layer z Porosity in plough pan 10-30 percent than that of puddled layer Hydragric horizon Subsurface horizon having characteristics associated with wet cultivation: z Fe-Mn accumulation or coatings of illuvial Fe and Mn; or, at least, 2x more Fed or 4x more Mnd than surface horizon; or z Redoximorphic features associated with wet cultivation; and z Thickness more than 10cm Genesis of Anthrosols Main soil-forming factors are: Man and Time Main soil-forming processes are centuries-long, recurrent, mono- management practices, for example: – Intensive fertilization – Continual application of earthy material – Irrigation with sediment-rich water – Wet cultivation Classification of Anthrosols z First qualifier: nature of the surface horizon (hortic, hydragric, irragric, plaggic, or terric) z Second qualifier: nature of the underlying soil or material, or of a special property (arenic, ferralic, gleyic, luvic, regic, spodic, or stagnic) Examples of Anthrosols (1) Ferrali-Hortic Anthrosol, Brazil (Terra Preta do Indio) 0-5 cm 5-38 cm 38-89 cm 89-124 cm 124-170 cm 170-210 cm 210-270 cm 270-360 cm 360-400 cm 012345678 Org. C (%) Examples of Anthrosols (2) Gleyi-Hydragric Anthrosol, Japan 0-16cm 16-46cm 46-60cm 60-83cm 83-108cm 108-140cm 0123456 % Fe (dithionite) Examples of Anthrosols (3) Regi-Irragric Anthrosol, China 0-28cm 28-54cm Gravel 54-100cm Sand Silt 100-110cm Clay 110-135cm 135-160cm 0% 20% 40% 60% 80% 100% Examples of Anthrosols (4) Spodi-Plaggic Anthrosol, The Netherlands Associated soils (1) Plaggic and Terric Anthrosols are associated with infertile soils such as Arenosols, Podzols and Albeluvisols, as well as with wetland soils (Fluvisols, Gleysols) Irragric Anthrosols are associated with dryland soils (Calcisols, Gypsisols, Solonchaks, Regosols, and Cambisols) Associated soils (2) Hydragric Anthrosols are associated with Fluvisols and Gleysols in low-lying areas, with Alisols, Acrisols, Lixisols and Luvisols in upland areas, and with Andosols in volcanic regions Hortic Anthrosols are associated with virtually any Reference Soil Group Associated soils (3) Soils comprising of “anthropogenic soil material” (urban waste, mine spoil, garbage dump, etc.) do not qualify for Anthrosol, because they lack evidence of pedogenetic change. They form a separate group within the Regosols, viz. Anthropic Regosols. Recently, a new RSG has been proposed to classify these soils as Technosols. Distribution of Anthrosols (1) z Plaggic and Terric Anthrosols occur mainly in Western Europe (Belgium, Germany, The Netherlands, UK and Ireland), covering some 500 000 ha z Large areas of Hydragric Anthrosols are found in the Far East (China, Japan, Philippines, Indonesia, Thailand and Vietnam) Distribution of Anthrosols (2) z Irragric Anthrosols are found in desert regions. Large tracts occur in the Middle East (Euphrates and Tigris valleys). z Hortic Anthrosols occur everywhere where long-term intensive cultivation has taken place. Technosols (proposed for WRB 2006) These are soils whose properties and pedogenesis are dominated by their technic origin or other profound human influence such as transportation. They are proposed to better accommodate urban, industrial, trafficked and military soils (referred to collectively as “urban soils”). Proposed diagnostics for Technosols Technic soil material: material dominated by artefacts and having properties substantially different from those of natural soil materials, and recognizable as such in the soil. Human-transported material: material moved into a pedon from a source area outside of its immediate vicinity by intentional human activity, and recognizable as such in the soil. Proposed definition for Technosols Keying out after Histosols and Anthrosols as: Other soils having • 50 per cent (by volume) or more human-transported or 20 per cent (by volume) or more technic soil material, or both, in any single layer or in combination totalling: – either 50 cm or more within 100 cm from the surface; or – at least half the depth to a lithic or paralithic contact shallower than 100 cm from the surface; or • a continuous, (almost) impermeable, constructed liner of any thickness within 100 cm from the surface; or • technic hard rock within 5 cm from the surface and covering at least 95 per cent of the horizontal extent of the pedon, underlain at some depth shallower than 200 cm by unconsolidated material. Examples of Technosols (1) Calcari-Spolic Technosol (Skeletic), Russia Examples of Technosols (2) Anthri-Urbic Technosol, Germany Examples of Technosols (3) Garbic Technosol (Reductic), Germany.