14 spaargaren soilprofiledescription2006 (1)

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Guidelines forSoil Description 2006

Otto Spaargaren

ISRIC – World Soil InformationWageningen

The Netherlands



Why soil descriptions ?

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

For research: as baseline record to illustratethe environmental setting and relationshipsbetween the soil attributes

For land resource development: as base forbuilding geo-referenced land information

systems



FAO Guidelines 2006

FAO Guidelines for Soil

Description. 4

th

Edition,2006.

Jointly prepared by

Universität Halle–Wittenberg,Germany

Universität Kiel, Germany

Leyte State University, ThePhilippines

ISRIC – World Soil Information,The Netherlands

Technische Universität München,Germany



Purpose of the FAO Guidelines

To enhance standardization and uniformity of

soil profile descriptions, in order to facilitatecross-references and comparison between soildescriptions

To contribute, through the objectivedescription and recording of soil properties,

both to the understanding of the land ofwhich the soil forms part, and to the reliabletransfer of technology



Sources for the 2006 FAO

Guidelines USDA Soil Survey Manual, 1993

USDA Field Book for Describing and SamplingSoils, Version 2.0, 2002

USDA Keys to Soil Taxonomy, 2003

Kartieranleitung 5, Ad-hoc-AG-Boden, 2005

Updated Global and National Soil and TerrainDigital Databases, ISRIC, 2005

World Reference Base for Soil Resources,2006



Content of the FAO Guidelines

General site information, registration andlocation

Soil formation factors

Soil description

Genetic and systematic interpretation – soil

classification



General Information Section

Profile number

Soil profile description status

Date of description

Author(s)

Location

Elevation

Map sheet number and grid reference(coordinates)



Soil formation factors

Atmospheric climate and weather conditions Soil climate Landform and topography (relief)

Major landform Position

Slope form Slope gradient

Land use and vegetation Land use Crops Human influence Vegetation

Parent material Age of the land surface



Soil description

Surface characteristics

Horizon boundary Primary constituents

Soil colour (matrix)

Mottling Soil redox potential and

reducing conditions

Carbonates Gypsum

Readily soluble salts

Field soil pH Soil odour

Andic characteristicsand volcanic glasses

Organic matter content

Organization of the soilconstituents

Bulk density

Voids (porosity)

Concentrations Biological activity

Human-made materials

Sampling



Genetic and systematic

interpretation – soil classification Soil horizon designation

Principles of classification according to WRB

Checklist of WRB diagnostic horizons,properties and materials

Appending texture and parent materialinformation to the reference soil group



Main changes from 1990 to 2006

New records in the soil description

Many new field procedures Many links from soil description records to soil

classification and interpretation

Expanded number of master horizons and theirsubordinate characteristics

Link to the World Reference Base for Soil Resources2006

Guidelines to provide more systematic and precise

information about texture, parent material andlayering



New records in soil description

Soil redox potential and reducing conditions

Determination of the redox potential by fieldmethod using a millivoltmeter and redox

electrodes (pg 36-37)

Reducing conditions Colour measurements (N, 2.5Y, 5Y, 5G, 5B)

α,α dipyridil test to show presence of Fe2+




Gypsum

Pseudomycelia,coarse-sized

crystals (nests,beards, coatings,groupings offibrous crystals),

loose to compactpowderyaccumulations

High EC




Readily soluble salts Traditionally: determined in laboratory (EC,

water-soluble salts determination)

New: field method using conductometermeasuring EC2.5 and converting the result into

salt % and ECSE. For the latter conversion anestimate of water content in the saturationextract has to be made (pg 40-41).




Soil odour

To record possible petrochemicalcontamination or other chemical reactions in

the soil that produce a distinct odour, e.g.oxidation of sulphides




Andic characteristics

Low bulk density (the soil is light) ; smearyconsistence is common

Field test: pH NaF; pH > 9.5 indicatespresence of abundant allophanic products

and/or organo-aluminium complexes;alternatively, red colour after applying NaFto soil sample spread on phenolphtaline paper

is indicative of high pH




Organic matter content

OM content can be estimated from soilcolour, taking into account the soil textural

class (pg 43).

Note of caution: method tends to overestimateOM content in soils of dry regions, and tounderestimate OM content in some tropicalsoils. Does not work well in strongly colouredsoils.




Bulk density

Field estimate byconsidering porosity,

coherence of soil material,and penetration resistance(pg 51)

Laboratory methods: fixedcore, Serin method




Human-made materials

Artefacts: solid or liquid substances that are

created or substantially modified by humansas part of an industrial or artisanalmanufacturing process; or

brought to the surface by human activity froma depth where they were not influenced bysurface processes




interpretation – soil classificationMaster horizon designation

Organic horizons:

H or O

H = wetO = dry

G d




interpretation – soil classificationMaster horizon designation

Mineral horizons:

A (organic matter)E (eluviation)

B (illuviation)C (unconsolidated parentmaterial)

R (consolidated parentmaterial)

G i d i




interpretation – soil classificationNew master horizon symbols, added in 2006:

I layer: Ice lenses and wedges that containat least 75% ice (by volume) and thatdistinctly separate organic or mineral layers

in the soil L layer: Sediment deposited in a body of

water composed of both organic and inorganicmaterials, also known as limnic material

W layer: Water layer in soils or water

submerging soils, either permanently or cyclicwithin the time frame of 24 hours

S b di t h t i ti f



Subordinate characteristics of

master horizonsa Highly decomposed organic materialb Buried genetic horizonc In mineral soils: concretions or nodules

In limnic material (L): coprogenous earthd In mineral soils: dense layer

In limnic material (L): diatomaceous earthe Moderately decomposed organic materialf Frozen soilg Stagnic conditionsh Accumulation of organic matter

S b di t h t i ti f




master horizonsi In mineral soils: slickensides

In organic soils: slightly decomposed organicmaterial

j Jarosite mottlingk Accumulation of pedogenetic carbonates

l Capillary fringe mottlingm In mineral soils: cementation or induration

In limnic material (L): marl

n Accumulation of sodiumo Residual accumulation of sesquioxidesp Ploughing or other disturbance

q Accumulation of silica

S b di t h t i ti f




master horizonsr Strong reductions Illuvial accumulation of sesquioxidest Accumulation of silicate clayu Urban and other man-made materialsv Occurrence of plinthitew Development of colour or structurex Fragipan charactery Accumulation of gypsumz Accumulation of salts more soluble than

gypsum@ Evidence of cryoturbation

G ti d t ti




interpretation – soil classification Soil taxonomic classification

WRB 2006 reference group name andrelevant qualifiers

FAO Legend (1974) and Revised Legend

(1988) Soil Map of the World Soil Taxonomy (2006)

National

Soil climate (Soil Taxonomy 2006)

Soil temperature regime Soil moisture regime



Texture and parent material

Guidelines are provided to refine information onthe WRB 2006 Reference Soil Groupsproviding information on:

Texture (standard textural classes) Lithology (according to SOTER 2005) Possible textural and/or lithological

discontinuities

E.g.:haCMdysl; SiL(UE2)/SSK(UG3)

Haplic Cambisol (Dystric, Siltic); silt loam from loessover sandy-skeletal from glacio-fluvial gravel



Afterthought

“In view of the high costs of soil survey, soil

descriptions should be made as detailed andcomprehensive as possible, so that theinformation can serve multiple purposes.”

14 spaargaren soilprofiledescription2006 (1)

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