Anthropic Soils
Concept of the Order
Anthropic Soils are soils that have been created or significantly altered by human activity. This includes truncation (i.e. excavation) of natural soils by earth-moving equipment, the relocation of soils from their original sites, or the mixing of natural soils in a way that significantly alters their original character. Additionally, Anthropic soils may be formed through the deposition of thick layers of organic or inorganic material, where they may also contain artefacts. Their classification reflects the way in which they were created or altered, and the kinds of materials used.
Correlation
Anthropic Soils were not formally part of the NZ Genetic Soil Classification, although Anthropic soils were described in some soil survey reports. In US Soil Taxonomy, the soils either correlate with soils containing an Anthropic or Plaggen Epipedon, Entisols, or are unclassified.
Occurrence
Anthropic Soils are most extensive in urban and peri-urban areas and areas that have been mined. While not necessarily covering extensive areas, soils sufficiently altered by Maōri are of particular cultural interest as the oldest examples of anthropogenic alteration of soils in New Zealand.
Accessory Properties of the Order
- Soil characteristics and the relationships between soils and landforms do not have the orderliness of natural soils.
- Drainage has often been changed significantly from the original state.
- Soil properties depend upon both the nature of the manufactured or natural materials and the nature of the soil manipulation.
- Land surfaces are artificial.
Summary of Anthropic Soils Hierarchy
| Code | Group | Subgroup |
|---|---|---|
| AT | Truncated | Rocky |
| Typic | ||
| AO | Māori | Artefact |
| Organic | ||
| Fill | ||
| AR | Refuse | Wet |
| Buried | ||
| Typic | ||
| AM | Mixed | Inverted-tephric |
| Inverted-mixed | ||
| Typic | ||
| AF | Fill | Compacted |
| Wet | ||
| Stony-Tailings | ||
| Earthy |
Key to Groups of Anthropic Soils
AT
Anthropic Soils that have been affected by truncation of the solum by the action of people. This truncation reached at least as deep as the natural in-situ A or AB horizon (i.e., to the upper boundary of the B horizon or deeper). The natural in-situ materials occur at or within 30 cm of the soil surface.
AO
Other Anthropic Soils that have been modified or altered through Māori cultural practice, often forming a distinct ‘cultural layer’ with artefacts (e.g. midden sites). These soils meet the following criteria:
- Contain additions to horizon(s) dominated by manufactured or natural mineral (e.g. rock fragments, sand), organic or biogenic material (e.g. seaweed, charcoal, ash, shells); and
- The horizon or combined horizons are at least 30 cm thick and have an upper boundary at the land surface, or within 90 cm if buried.
AR
Other Anthropic Soils that have either
- a layer comprising natural organic waste, or manufactured organic material, including plastics, that is at least 30 cm thick and has an upper boundary at the land surface, or is buried within 90 cm of the land surface, or
- has a methane content sufficient to be detected by odour.
AM
Other Anthropic Soils in which the original soil horizonation has been destroyed by deep ripping, deep subsoil lifting, or similar practices.
AF
Other Anthropic Soils.
Key to Subgroups of Anthropic Soils
AT - TRUNCATED ANTHROPIC SOILS
Truncated Anthropic Soils result from cutting away any existing soil, by mechanical equipment, leaving material that would be recognised as a BC, C or R horizon. The scalped surface may be overlain by up to 29 cm of soil, deposited for landscaping purposes.
ATX
Soils with a lithic contact within 60 cm of the soil surface.
Rocky Truncated Anthropic Soils
ATT
Other soils.
Typic Truncated Anthropic Soils
AO - MĀORI ANTHROPIC SOILS
These soils are attributed to Māori cultural activity, such as Māori-initiated construction or burial, gardening and horticultural practice, or signs of customary resource activity. Māori Anthropic Soils occur throughout New Zealand, at sites where Māori cultural activity has significantly altered the soil profile, through alteration, excavation and/or redistribution of soil from original sites. Examples include pā sites, trenches, cultural fortifications, villages (papa kāinga), burial sites (ūrupa). For gardening, horticulture, and cropping soil management practices result in the addition of local mineral material (e.g., rock fragments and sand) or the addition of organic or biogenic material (e.g., seaweed, charcoal, ash, shells), to ameliorate and enhance the physical, chemical, and biological properties of a soil (e.g., soil fertility, drainage, aeration, temperature). Customary resource activity often results in waste material altering soils and landforms (e.g., middens).
AOA
Soils with a horizon containing Māori artefacts or other manufactured material (e.g., some middens), or a horizon resulting from excavation and redistribution of soil material for construction purposes (e.g., Pā sites, fortifications, burial sites), greater than a combined thickness of 30 cm within 90 cm of the mineral soil surface.
Artefact Māori Anthropic Soils
AOB
Soils with a horizon containing organic material (plant- or animal-derived) added by Māori primarily to enhance soil conditions with a thickness greater than 30 cm within 90 cm of the mineral soil surface.
Organic Māori Anthropic Soils
AOF
Other soils with a horizon containing additions by Māori greater than a combined thickness of 30 cm within 90 cm of the mineral soil surface.
Fill Māori Anthropic Soils
AR - REFUSE ANTHROPIC SOILS
Refuse Anthropic Soils occur in sites where household, land management, urban or industrial waste has been dumped and which have significant organic matter, comprising vegetation, animal or manufactured material such as plastics, paper or timber.
ARW
Refuse anthropic soils that are saturated within 60 cm of the mineral soil surface at some time of the year.
Wet Refuse Anthropic Soils
ARB
Soils in which organic refuse is buried beneath an overburden of soil or rock material greater than 30 cm thick.
Buried Refuse Anthropic Soils
ART
Other Soils.
Typic Refuse Anthropic Soils
AM - MIXED ANTHROPIC SOILS
Mixed Anthropic Soils occur in sites where the original soil has been disturbed by mechanical procedures such as deep ripping, lifting, flipping or recontouring (e.g. hump-and-hollowing) to improve soil characteristics such as increasing fertility, or breaking up drainage-impeding horizons (e.g. placic horizons, ortstein- or ironstone-pans). The original soil, if known, may be appended to the name in parentheses, for example Typic Mixed Anthropic Soil (Perch-Gley Pallic Soil).
AMI
Soils comprising a modified tephra stratigraphy by mechanical flipping to a depth greater than 30 cm from the mineral soil surface.
Inverted-tephric Mixed Anthropic Soils
AMZ
Soils comprising a soil horizon stratigraphy that is modfified by mechanical flipping, lifting, or mixing to a depth greater than 30 cm from the mineral soil surface in order to improve drainage by breaking up drainage-impeding soil horizons, often combined with recontouring of the soil surface (e.g., hump-and-hollowing).
Inverted-impeded Mixed Anthropic Soils
AMT
Other soils mechanically mixed to a depth greater than 30 cm from the mineral soil surface.
Typic Mixed Anthropic Soils
AF - FILL ANTHROPIC SOILS
Fill Anthropic Soils result from the deposition of dominantly inorganic material including imported soil, rock debris, dredged sediments or manufactured material such as bricks, concrete, or metals.
AFC
Soils that have been compacted and have a bulk density of 1.5 Mg/m3 or more.
Compacted Fill Anthropic Soils
AFW
Other soils that are wet within 60 cm of the mineral soil surface at some time of the year.
Wet Fill Anthropic Soils
AFST
Other soils that have a coarse layer (e.g. imported rock fragments, concrete, bricks) more than 30 cm thick in which there is insufficient fine-earth to fill more than half the interstices between the fragments, with an upper boundary within 60 cm of the mineral soil surface.
Stony-tailings Fill Anthropic Soils
AFT
Other soils.
Typic Fill Anthropic Soils