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CHARGES: ICOMANTH is charged with defining appropriate classes in Soil Taxonomy for soils that have their major properties derived from human activities. The committee should establish which criteria significantly reflect human activities, or when a soil’s properties are dominantly the result of human activities.

NOTE: There is a new ICOMANTH Web site at the following WWW URL address:

http://wwwscas.cit.cornell.edu/icomanth (now inactive)

In August 1995, ICOMANTH chairman Dr. Ray B. Bryant of Cornell University mailed out Circular Letter No. 1. The circular contained some background material concerning ICOMANTH and the study of soils where humans have profoundly affected formation or existing morphology. Dr. Bryant posed seven conceptual questions concerning Anthropogenic soils. Included in this 2nd Circular Letter are:

• Responses to the question areas from Circular Letter No. 1
• Examples of effects of humans on soils
• Terms to describe human activities and human-modified materials
• A brief history of the ways that human modified or transported soils have been recognized in Soil Taxonomy
• Conceptual questions for the committee members.

Committee members and other interested persons are asked to do the following:

• Carefully review the questions and proposals and submit comment by 9/31/97.
• Persons interested in serving on a subcommittee proposing diagnostic horizons and definitions should reply to Dr. Bryant by 12/1/97.
• Please submit copies (electronic if possible, hardcopy if not) of lab and description data of Anthropogenic soils and soil materials to Dr. Bryant beginning 8/1/97.
• Please submit copies of slides (electronic if possible) or prints of Anthropogenic soils and soil materials to Dr. Bryant beginning 8/1/97.

Dr. John M. Galbraith
Cornell University

Members may forward this letter to others who would like to be placed on the ICOMANTH mailing list.

Dr. Ray B. Bryant, ICOMANTH Chair Dept. Soil, Crop, & Atm. Sciences Rm 709 Bradfield Hall, Tower Road Cornell University Ithaca, NY 14853-1901 USA

Phone: 607-255-1716 FAX: 607-255-2644 E-mail: rbb1@cornell.edu WWW URL address: http://wwwscas.cit.cornell.edu/rbb1/index.html (select "Links" button)

HUMAN MODIFIED AND HUMAN TRANSPORTED SOILS

(1) Some Anthropogenic activities that have profound affect on soils, soil formation, and landform creation or removal

There are fewer and fewer places on earth where humans have not disturbed, transported, or modified the soil in some manner. The soil and landform modifications by humans that are not practically reversed and produce long-lasting effects that can be consistently identified by different scientists are distinguished in Table 1. Other activities either have unknown effect, cannot be easily quantified or distinguished, or can be easily reversed to restore previous soil properties.

Table 1. The effects of some Anthropogenic activities on soils

Long-term effects

deposition of dredged sulfidic material in oxidizing landform positions

exposure of sulfidic material to oxidation by excavation or deposition

accelerated erosion of cropland by wind and water

accelerated erosion of rangeland by wind and water

land filling with transported soil and/or rock

land filling with debris, refuse, waste, scrap, and ash

land filling with dredged sediments

land leveling of soils

land leveling for irrigation

removal and filling of soil and rock during excavation

mass movement (slippage, landslides) after human landscape modification

surface removal (removing topsoil or organic material such as peat)

changing surface texture by conventional plowing

changing surface reaction by conventional plowing (calcification)

destroying shallow (<18cm) diagnostic horizons by conventional plowing

contamination by airborne heavy metals

contamination by heavy metal or radioactive additives and spills

contamination by inorganic chemicals or organic pollutants or toxins

deep plowing that destroys diagnostic horizons

deep mixing of shallow diagnostic horizons during logging operations

addition of asphalt layers or synthetic water barriers and landfill liners

severe compaction by machinery during filling

severe surface compaction by machinery or human traffic

sedimentation in fields by soil material from human caused accelerated erosion

sedimentation in floodplains by material from human caused accelerated erosion

eolian deposition of soil material from human caused accelerated erosion

sedimentation in fields from frequent irrigation

reduction/illuviation/oxidation of Fe and Mn by artificial saturation (paddy soil)

Table 1 (cont.)

Site and soil-dependent effects

liming by chemical or mineral additives to offset natural acidification

addition of chemicals or minerals that acidify soils

addition of air pollutants that result in acid rain

artificial drainage of sulfidic material that results in extreme acidification

prevention of frequent flooding

artificial flooding or raising of shallow water tables by water impoundment

creation of sodic or natric soils by alteration of natural drainage or irrigation

 

Short-term or reversible effects

recycling of soil fertility by slash/burn rotational farming

changing surface compaction, structure by conventional plowing

loss of surface organic matter (increased oxidation, loss by erosion)

loss of soil fertility (exportation in crops, loss by erosion)

changing soil fertility by fertilizing

artificial drainage of soil

creation of saline seeps

alteration of runoff by ditching or terracing

(2) Proposed Terms to Describe Human Activities and Products

Anthropogenic (also appears as Anthrogenic in some papers) activities - Human actions that control soil forming processes. Examples are: excavation and deposition of soil and rock, contamination with pollutants, long term alteration of soil reaction by liming, artificial flooding, long term drainage alteration, long term protection from natural flooding, mechanical mixing and soil compaction, and accelerated erosion.

Excavation – the removal of rock and earthy material. Removal of more than 50 cm by human activity or machinery constitutes creation of an artificial landform.

Anthropic deposition – the deposition, reclamation, or replacement of artifacts, rock, organic and mineral soil material. Deposition of more than 50cm constitutes creation of an artificial landform.

Artificial landform - an area in the landscape as large or larger than a polypedon that has evidence of mining or reclamation, excavation more than 50cm deep, or Anthropic deposition more than 50cm thick. Evidence may be morphological, chemical, mineralogical, historical, or comparative polypedon/landform study.

Anthropogeomorphic (appears as Anthrogeomorphic in some papers) activities - Excavation and Anthropic deposition (cutting, filling, and leveling) that results in alteration of the shape of a natural landform or creation of an artificial landform.

Anthropoturbation - mixing of different horizons or mixing within a horizon that occurs because of human activity or machinery. (a type of Anthropopedogenesis).

Anthropoturbated material - organic material, artifacts, soils, or rocks with evidence of being mixed by human activity or machinery.

Artifacts - human altered material such as coal ash, iron ore slag, asphalt, human refuse such as garbage or sewage sludge, human processed natural materials such as lumber, and human manufactured material such as plastic, fiberglass, brick, cinder block, concrete, iron and steel, organic byproducts, and other building debris. Garbage or refuse fragments include: food and household cooking waste, soiled rags and paper cleaning products, broken household objects, empty glass, paper, and plastic containers and bags, mail, magazines, and newspapers, and simple household construction materials normally disposed of by homeowners and transported to dumps and landfills.

Anthropotransported material - Artifacts deposited on the landscape; and manure, soil, and rock with evidence of being transported by human activity or machinery, including dredged sediment and sediment in irrigation water.

Anthric (Anthropic) saturation - (already in Soil Taxonomy) episaturation by human-controlled flooding or irrigation which results in reduction and oxidation of iron and manganese compounds and long term changes in soil properties (Anthraquic conditions), a type of Anthropopedogenesis.

Artificial drainage - lowering of a ground water table.

Anthropic compaction – the reduction in the volume of pores per unit mass of soil by human activity or machinery. (a type of Anthropopedogenesis)

Anthropocompacted material - material with reduced volume of pores per unit mass of soil as a result of human activity.

(3) Current Diagnostic Horizons, Properties, And Characteristics in Soil Taxonomy That Describe the Effects of Anthropopedogenesis and Anthropogeomorphogenesis

Soil Taxonomy recognizes human effects on the soil with Anthropic and Plaggen epipedons, the Agric diagnostic horizon, and the Anthraquic conditions diagnostic characteristic. Cambic horizons develop within decades in some transported soils, Sulfuric horizons and sulfidic material occur in mine spoil and dredged sediment, and humanly compacted material may qualify as densic material, although these differentiae are not restricted to human-affected soils (Engel and Ahrens, 1997). The "Verm" (wormholes) great groups also may represent the affect of long term human cultivation. Soil material recently transported by humans may be described as a mantle of new material above buried soils.

The classes that exist in the 8^th Ed. of Soil Taxonomy and those officially proposed occur in Table 2. In addition, USDA-NRCS Soil Taxonomy Staff (Engel, 1997 unpublished data) has suggested modification of the Plaggepts suborder.

Table 2. Classes In Soil Taxonomy That Identify Anthropogenic Soils

(4) The Major Types of Anthropogenic Soils

Several major types of Anthropogenic soils have become apparent. Deeply mixed or plowed soils have mechanical disturbance that has destroyed all or most of the diagnostic horizons. Paddy soils have artificial saturation and have been puddled with profoundly accelerated natural eluviation and illuviation processes (Anthraquic conditions). Long-term cultivation, improper logging practices, and overgrazing produces soils with accelerated erosion and nearby deposition. Long term cultivated and irrigated soils in arid areas have uncharacteristically dark surface horizons. In humid areas, long-term cultivated soils may have subsoils with profoundly accelerated natural eluviation (Agric horizons) or uncharacteristically high reaction, Phosphorous, and wormhole content. Soils with buried artifacts, thick mantles of human transported material and deeply excavated surfaces occur in many urban and intensively cultivated regions. Polluted soils have unnatural concentrations of heavy metals, organic compounds, or radioactivity.

The major soil-forming factors associated with all Anthropogenic soils are human activity and parent material. In mixed soils, genetic horizons are combined, thus undoing the work of previous soil genesis. In heavily amended soils, the effects of previous leaching and weathering are reversed. For many transported soils, the genetic time clock is reset by exposure of unweathered natural and manufactured material at or closer to the surface.

Anthropogenic soils may have physical evidence of their transportation or excavation, or they occur on artificial landforms. Many Anthropogenic soils in urban environments contain artifacts, garbage, building debris, natural genetic soil fragments in unnatural arrangement, irregular Carbon distribution, buried genetic horizons, or lithologic discontinuities that mark the depth of their alteration or deposition. Deeply mixed soils on natural landforms in agricultural environments retain fragments of natural genetic horizons arranged in unnatural patterns or positions. Chemically modified or limed soils show uncharacteristic reaction, fertility, high radioactivity, chemical toxicity to humans or organisms, heavy metal concentration, or base saturation compared to nearby soils. Some continuously plowed soils show accumulations of illuviated material directly below the plow layer. Paddy soils and some irrigated soils show Anthraquic conditions (uncharacteristic accumulations of illuviated Fe and Mn directly below the saturated or puddled layer).

Several other recent papers have suggested major types of Anthropogenic soils and Anthropopedogenetic activities (Fanning and Fanning, 1989; Eswaran, 1997, unpublished data; Zitong, 1994; Kosse, 1995, unpublished data). Copies of these papers may be obtained from the ICOMANTH Web page or by request to Dr. Bryant.