Soil Profile Description Otto Spaargaren ISRIC – World Soil Information Wageningen The Netherlands.

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

FAO Guidelines forSoil Profile Description.3rd Edition.

1990 – English1993 – French

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 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

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 location Soil classification Landform and topography Land use and vegetation Parent material Surface characteristics Soil-water relationships

General information (1) :Registration and location

Profile number Soil profile description status Date of description Author(s) Soil unit Location Elevation Map sheet number and grid reference Coordinates

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

Topography Landform Land element Position Slope Micro-topography Soil-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 dimensions Soil colour Primary constituents Organization of the constituents Voids (porosity) Concentrations Biological activity Soil reaction Samples

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) :

Master horizon designation (1)

Organic horizons:

H or O

H = wetO = dry

Soil horizon description (3) :

Master horizon designation (2)

Mineral horizons:

A (organic matter)E (eluviation)B (illuviation)C (parent material, unconsolidated)

Soil horizon description (4) :

Master horizon designation (3)

Mineral horizons:

R (parent rock)

Soil horizon description (5) :

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

Soil horizon description (6) :

Subordinate characteristics of master horizons (2):

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

Soil horizon description (7) :

Subordinate characteristics of master horizons (3):

v Occurrence of plinthitewDevelopment of colour or structurex Fragipan charactery Accumulation of gypsumz Accumulation of salts more soluble than

gypsum

Soil horizon description (8) :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 (9) :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 (10) :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 (11) :Voids (porosity)

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

– Type– Size– Abundance– Continuity– Orientation

Soil horizon description (12) :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 (13) :Biological activity

Roots – abundance and size

Biological features – abundance and kind

Soil horizon description (14) :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 (15) :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 2002, a new “Field Book

for Describing and Sampling

Soils” (Version 2.0) was

issued by the National Soil

Survey Center of the

USDA’s Natural Resources

Conservation Service

New developments

In 2003, a “Students Guide for Soil Description, Soil Classification and Site Evaluation” was prepared by R. Jahn, H.-P. Blume and V.B. Asio, for workshops and international seminars in Poland and The Philippines

New developments

In 2003, FAO and CSIC issued “The MultilingualSoil Profile Database” (SDBm Plus), an upgraded and expandedWindows version of theSDBm 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)

The Student Guide

Builds strongly on the 1990 Guidelines, with elements of the “Kartieranleitung” (Germany, 1994), SOTER (1995), WRB (1998), and Soil Taxonomy (1999)

Links observation to interpretation

Biased towards soil conditions in temperate regions

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)

Conclusions (1)

There is a need to update the 1990 FAO Guidelines for Soil Profile Description, in order to accommodate new knowledge and needs for recording soil properties

The new USDA Field Book and the Student Guide provide good practical material to be incorporated in a 4th Edition of the Guidelines, enhancing the interpretative value

Conclusions (2)

Special attention should be paid to the consequences of changes with respect to the older versions of the Guidelines (see, for example, the change in textural boundaries in 1990)

Care should be taken that presented methods are valid worldwide, or that users are cautioned for the limited validity of methods given

Afterthought

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