soil profile description

Soil Profile Description

Otto Spaargaren

ISRIC – World Soil Information

WageningenThe Netherlands

Why soil profile descriptions ?

In surveys: as typical example of soil mapping unit or of one of its components

For research: as baseline record to illustrate the environmental setting and relationships between the soil attributes

For land resource development: as base for building geo-referenced land information systems

Guidelines (1)

FAO Guidelines forSoil Profile Description.3rd Edition.

1990 – English1993 – French

Guidelines (2)

2005. Draft FAO Guidelines for Soil Profile Description and Classification. 4th Edition

Prepared jointly byUniversität Halle – Würtenberg, GermanyUniversität Kiel, GermanyLeyte State University, PhilippinesISRIC – World Soil Information, The

Netherlands

Purpose of the FAO Guidelines

To enhance standardization and uniformity of soil profile descriptions, in order to facilitate cross-references and comparison between soil descriptions

To contribute, through the objective description and recording of soil properties, both to the understanding of the land of which the soil forms part, and to the reliable transfer of technology

Sources for the 1990 FAO Guidelines

USDA Soil Survey Manual

Revised Legend of the Soil Map of the World

Keys to Soil Taxonomy

Australian Soil and Land Survey Field Handbook

Additional sources for the 2005 FAO Guidelines

World Reference Base for Soil Resources

USDA Field Book for Describing and Sampling Soils

1999 Soil Taxonomy and 2003 Keys to ST

AG-Boden 2004. KA5: Bodenkundliche Kartieranleitung – 5. Auflage

Content of the FAO Guidelines

General information about the soil, both administratively and environmentally

Description of the individual soil horizons

Linkage to computerized information systems, in particular the FAO-ISRIC Soil Database (SDB)

General Information Section

Registration and locationSoil classificationLandform and topographyLand use and vegetationParent materialSurface characteristicsSoil-water relationships

General information (1) :Registration and location

Profile numberSoil profile description statusDate of descriptionAuthor(s)Soil unitLocationElevationMap sheet number and grid referenceCoordinates

General information (2) :Soil classification

Soil taxonomic classification

– WRB reference group name– FAO Legend (1974) and Revised Legend (1988)

Soil Map of the World– Soil Taxonomy (1999)– National

Soil climate

General information (3) :Landform and topography

TopographyLandformLand elementPositionSlopeMicro-topographySoil-landscape sequential relationships

General information (4) :Land use and vegetation

Land use

Human influence

Vegetation

General information (5) :Parent material

Parent material– Unconsolidated material– Rock type

Effective soil depth

General information (6) :Surface characteristics

Rock outcrops

Surface coarse fragments

Erosion

Surface sealing

Surface cracks

Other surface characteristics

General information (7) :Soil-water relationships

Drainage class

Internal drainage

External drainage

Flooding

Groundwater

Moisture conditions of the soil

Soil horizon description

Horizon designation and dimensionsSoil colourPrimary constituentsOrganization of the constituentsVoids (porosity)ConcentrationsBiological activitySoil reactionSamples

Soil horizon description (1) :Designation and dimensions

Horizon symbol – H, O, A, E, B, C and R master horizon nomenclature, and the subordinate characteristics within master horizons and layers

Horizon boundary – depth, distinctness and topography

Soil horizon description (2) :Additional 2005 horizon symbols

New master horizon symbolsI layer: Ice lenses and wedges that contain at least 75% ice (by volume) and that distinctly separate organic or mineral layers in the soil

L layer: Sediment deposited in a body of water composed of both organic and inorganic materials, also known as limnic soil material

W layer: Water layer in soils or flooded soils, where flooding is either permanent or cyclic

Soil horizon description (3) :

Master horizon designation (1)

Organic horizons:H or OH = wetO = dry



Mineral horizons:A (organic matter)E (eluviation)B (illuviation)C (parent material,

unconsolidated)



Mineral horizons:R (parent rock)


Subordinate characteristics of master horizons (1):

c Concretions or nodulesf Frozen soilg Gleying evidenced by mottlingh Accumulation of organic matterj Jarosite mottlingk Accumulation of carbonatesm Cementation or induration



n Accumulation of sodiumo Residual accumulation of sesquioxidesp Ploughing or other disturbanceq Accumulation of silicar Strong reductions Illuvial accumulation of sesquioxidest Accumulation of silicate clay



v Occurrence of plinthitew Development of colour or structurex Fragipan charactery Accumulation of gypsumz Accumulation of salts more soluble than gypsum


New 2005 subordinate characteristics of master horizons (1):

a Highly decomposed organic materialb Buried horizonc In combination with L: Coprogenous earth d Dense layer (physically root-restrictive; not

used in combination with m). In combination withL: Diatomaceous earth


New 2005 subordinate characteristics of master horizons (2):

e Moderately decomposed organic materiali Slickensides. In combination with H or O:

Slightly decomposed organic materialm In combination with L: Marlu Urban and other man-made materials@ Evidence of cryoturbation

Soil horizon description (10) :Soil colour

Matrix colour – hue, value and chroma, both dry and moist, according to the Munsell Soil Color Charts, or the Revised Standard Soil Color Charts

Mottling – abundance, size, contrast, boundary and colour (dry and moist)

Soil horizon description (11) :Primary constituents

Texture of the fine earth fraction – sand, loamy sand, sandy loam, loam, silt loam, silt, silty clay loam, silty clay, clay loam, sandy clay loam, sandy clay, clay

Rock fragments – gravel, stones, boulders

Soil horizon description (12) :Organization of soil constituents

Soil structure – grade, size and type– Types: single grain, massive, granular, prismatic,

columnar, angular blocky, subangular blocky, platy, rock structure, stratified structure

Consistence – dry, moist and wet

Soil horizon description (13) :Voids (porosity)

Voids include all space in the soil. They are described in terms of

– Type– Size– Abundance– Continuity– Orientation

Soil horizon description (14) :Concentrations

Cutanic features – clay, humus, pressure faces, slickensides, iron coatings

Cementation and compaction – continuity, structure, nature, degree

Mineral nodules – abundance, kind, size, shape, hardness, nature, colour

Soil horizon description (15) :Biological activity

Roots – abundance and size

Biological features – abundance and kind

Soil horizon description (16) :Soil reaction

Presence of carbonates – non-calcareous, slightly calcareous, moderately calcareous, strongly calcareous and extremely calcareous (tested with 10% HCl)

Field pH – Hellige test, field pH meter, NaF test for volcanic soils

Soil horizon description (17) :Soil odour

New in the draft Guidelines of 2005 is the recording of odour. This gives the opportunity to indicate the presence of petrochemical substances or sulphurous compounds (the smell of “rotten eggs”).

Soil horizon description (18) :Samples

Basically, there are two methods of collecting soil samples:

– Sampling in equal proportions over the whole horizon (recommended method)

– Sampling in equal proportions within a depth of 20cm, either from the centre of the horizon, or at balanced intervals if the horizon exceeds 50cm thickness

Linkages (1) :FAO-ISRIC Soil Database (SDB)

Permits storage and retrieval of large amounts of field and analytical data

Provides a flexible coding system to accommodate local needs

Can be linked to geographical information systems (GIS), automated land evaluation packages, or statistical programs

Linkages (2) :FAO-ISRIC Soil Database (SDB)

The following data sets can be stored in the SDB:

Field descriptions: coded information on site and profile characteristics

Standard soil analytical results: chemical analyses, soluble salts

Soil physical analytical results: infiltration and water retention data

New developments

In 2003, FAO and CSIC issued “The Multilingual Soil Profile Database” (SDBm Plus), an upgraded and expanded Windows version of the SDBm software, whichhad replaced the DOS-

based version of SDB.

The USDA Field Book

Very comprehensive, with numerous useful diagrams and illustrations

Introduces new descriptive elements, such as “redoximorphic features”, “soil crusts”, and “odor”

Provides little linkage to the FAO Guidelines (e.g. no comparison between particle size classes of USDA and FAO)

SDBm Plus (1)

Re-designed and re-written as Windows application

Multilingual (English, French, Spanish, German)

Detailed soil profile characterization

SDBm Plus (2)

Possibility of monitoring the temporal variability of analytical, physical and hydraulic soil properties

Metadata facility for describing analytical methods and procedures used

Linkage between database and land evaluation/geographical information systems (LES/GIS)

Afterthought

“In view of the high costs of soil survey, soilprofile descriptions should be made as detailed and comprehensive as possible, so that they can serve multiple purposes.”

soil profile description

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