Guidelines forSoil Description 2006 Otto Spaargaren ISRIC – World Soil Information Wageningen The Netherlands Why soil 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 Jointly prepared by Universität Halle–Wittenberg. 4th Edition. 2006. Germany Leyte State University. Germany Universität Kiel. Germany .FAO Guidelines 2006 FAO Guidelines for Soil Description. The Netherlands Technische Universität München. The Philippines ISRIC – World Soil Information. in order to facilitate cross-references and comparison between soil descriptions To contribute.Purpose of the FAO Guidelines To enhance standardization and uniformity of soil profile descriptions. and to the reliable transfer of technology . both to the understanding of the land of which the soil forms part. through the objective description and recording of soil properties. Ad-hoc-AG-Boden.Sources for the 2006 FAO Guidelines USDA Soil Survey Manual. 2005 World Reference Base for Soil Resources. 2002 USDA Keys to Soil Taxonomy.0. 2003 Kartieranleitung 5. Version 2. 1993 USDA Field Book for Describing and Sampling Soils. 2005 Updated Global and National Soil and Terrain Digital Databases. 2006 . ISRIC. registration and location Soil formation factors Soil description Genetic and systematic interpretation – soil classification .Content of the FAO Guidelines General site information. 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 Andic 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 and volcanic glasses Organic matter content Organization of the soil constituents Bulk density Voids (porosity) Concentrations Biological activity Human-made materials Sampling . properties and materials Appending texture and parent material information to the reference soil group .Genetic and systematic interpretation – soil classification Soil horizon designation Principles of classification according to WRB Checklist of WRB diagnostic horizons. 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 their subordinate characteristics Link to the World Reference Base for Soil Resources 2006 Guidelines to provide more systematic and precise information about texture. parent material and layering . 5G.α dipyridil test to show presence of Fe2+ .5Y. 5B) α. 2. 5Y.New records in soil description Soil redox potential and reducing conditions Determination of the redox potential by field method using a millivoltmeter and redox electrodes (pg 36-37) Reducing conditions Colour measurements (N. coatings. coarse-sized crystals (nests.New records in soil description Gypsum Pseudomycelia. groupings of fibrous crystals). beards. loose to compact powdery accumulations High EC . For the latter conversion an estimate of water content in the saturation extract has to be made (pg 40-41). water-soluble salts determination) New: field method using conductometer measuring EC2. .New records in soil description Readily soluble salts Traditionally: determined in laboratory (EC.5 and converting the result into salt % and ECSE. g. oxidation of sulphides .New records in soil description Soil odour To record possible petrochemical contamination or other chemical reactions in the soil that produce a distinct odour. e. New records in soil description Andic characteristics Low bulk density (the soil is light). smeary consistence is common Field test: pH NaF. red colour after applying NaF to soil sample spread on phenolphtaline paper is indicative of high pH . pH > 9.5 indicates presence of abundant allophanic products and/or organo-aluminium complexes. alternatively. . Does not work well in strongly coloured soils. taking into account the soil textural class (pg 43).New records in soil description Organic matter content OM content can be estimated from soil colour. and to underestimate OM content in some tropical soils. Note of caution: method tends to overestimate OM content in soils of dry regions. Serin method . and penetration resistance (pg 51) Laboratory methods: fixed core.New records in soil description Bulk density Field estimate by considering porosity. coherence of soil material. New records in soil description Human-made materials Artefacts: solid or liquid substances that are created or substantially modified by humans as part of an industrial or artisanal manufacturing process. or brought to the surface by human activity from a depth where they were not influenced by surface processes . Genetic and systematic interpretation – soil classification Master horizon designation Organic horizons: H or O H = wet O = dry . Genetic and systematic interpretation – soil classification Master horizon designation Mineral horizons: A E B C (organic matter) (eluviation) (illuviation) (unconsolidated parent material) R (consolidated parent material) . added in 2006: I 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 material W layer: Water layer in soils or water submerging soils.Genetic and systematic interpretation – soil classification New master horizon symbols. either permanently or cyclic within the time frame of 24 hours . Subordinate characteristics of master horizons a b c d e f g h Highly decomposed organic material Buried genetic horizon In mineral soils: concretions or nodules In limnic material (L): coprogenous earth In mineral soils: dense layer In limnic material (L): diatomaceous earth Moderately decomposed organic material Frozen soil Stagnic conditions Accumulation of organic matter . Subordinate characteristics of master horizons i j k l m n o p q In mineral soils: slickensides In organic soils: slightly decomposed organic material Jarosite mottling Accumulation of pedogenetic carbonates Capillary fringe mottling In mineral soils: cementation or induration In limnic material (L): marl Accumulation of sodium Residual accumulation of sesquioxides Ploughing or other disturbance Accumulation of silica . Subordinate characteristics of master horizons r s t u v w x y z @ Strong reduction Illuvial accumulation of sesquioxides Accumulation of silicate clay Urban and other man-made materials Occurrence of plinthite Development of colour or structure Fragipan character Accumulation of gypsum Accumulation of salts more soluble than gypsum Evidence of cryoturbation . Genetic and systematic interpretation – soil classification Soil taxonomic classification WRB 2006 reference group name and relevant 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 . silt loam from loess over sandy-skeletal from glacio-fluvial gravel . SiL(UE2)/SSK(UG3) Haplic Cambisol (Dystric.g.: haCMdysl.Texture and parent material Guidelines are provided to refine information on the WRB 2006 Reference Soil Groups providing information on: Texture (standard textural classes) Lithology (according to SOTER 2005) Possible textural and/or lithological discontinuities E. Siltic). Afterthought “In view of the high costs of soil survey. soil descriptions should be made as detailed and comprehensive as possible. so that the information can serve multiple purposes.” .