Diagnostic criteria Flashcards
anthraquic horizon
paddy soils: The layer comprising the puddled layer and the plough pan, both showing a reduced matrix and oxidized root channels.
hortic horizon
It is dark, has a high content of organic matter and phosphorus (P), high animal activity, and high base saturation; resulting from long-term cultivation, fertilization, and application of organic residues.
hydragric horizon
paddy soils: The layer below the anthraquic horizon showing redoximorphic features and/or an accumulation of iron (Fe) and/or manganese (Mn).
irragric horizon
A uniformly textured layer with at least moderate content of organic matter and high animal activity, gradually built up by sediment-rich irrigation water.
plaggic horizon
A dark layer with at least moderate content of organic matter, sandy or loamy; resulting from the application of sods and excrements.
pretic horizon
A dark layer with at least moderate content of organic matter and phosphorus (P), high contents of exchangeable calcium (Ca) and magnesium (Mg), including Amazonian Dark Earths.
terric horizon
It shows evidence of the addition of substantially different material, with at least moderate content of organic matter and high base saturation; resulting from adding mineral material (with or without organic residues) and cultivation.
calcic horizon
A horizon with an accumulation of secondary carbonates that are not continuously cemented.
cryic horizon
A horizon that is perennially frozen, showing visible ice or temperatures below 0°C if water is insufficient.
salic horizon
A horizon with high amounts of readily soluble salts.
thionic horizon
A horizon with sulfuric acid and a very low pH value.
folic horizon
An organic layer that is not water-saturated and not drained.
histic horizon
An organic layer that is water-saturated or drained.
chernic horizon
A thick, very dark-coloured horizon with high base saturation, moderate to high content of organic matter, and well-developed soil structure or structural elements created by agricultural practices.
mollic horizon
A thick, dark-coloured horizon with high base saturation and moderate to high content of organic matter, with at least some soil structure or structural elements created by agricultural practices.
umbric horizon
A thick, dark-coloured horizon with low base saturation and moderate to high content of organic matter, with at least some soil structure or structural elements created by agricultural practices.
argic horizon
A subsurface layer with distinctly higher clay content than the overlying layer, without a lithic discontinuity and/or presence of illuvial clay minerals.
duric horizon
A horizon with concretions or nodules cemented by secondary silica, and/or remnants of a broken-up petroduric horizon.
ferric horizon
A horizon containing ≥ 5% reddish to blackish concretions and/or nodules and/or ≥ 15% reddish to blackish coarse masses, with accumulation of Fe (and Mn) oxides.
gypsic horizon
A horizon with an accumulation of secondary gypsum that is not continuously cemented.
limonic horizon
A horizon with accumulation of Fe and/or Mn oxides in a layer that has or had gleyic properties; at least partially cemented.
natric horizon
A subsurface layer with distinctly higher clay content than the overlying layer, without a lithic discontinuity and/or presence of illuvial clay minerals; high content of exchangeable sodium (Na).
petrocalcic
A horizon with an accumulation of secondary carbonates that are relatively continuously cemented.
petroduric horizon
A horizon with an accumulation of secondary silica that is relatively continuously cemented.
petrogypsic horizon
A horizon with an accumulation of secondary gypsum that is relatively continuously cemented.
petroplinthic horizon
A horizon consisting of oximorphic features inside (former) soil aggregates that are at least partially interconnected and have a yellowish, reddish and/or blackish colour; high contents of Fe oxides; relatively continuously cemented.
pisoplinthic horizon
A horizon with ≥ 40% at least moderately cemented yellowish, reddish, and/or blackish concretions and/or nodules, with accumulation of Fe oxides.
plinthic horizon
A horizon that has in ≥ 15% of its exposed area oximorphic features inside (former) soil aggregates that are black or have a redder hue and a higher chroma than the surrounding material; high contents of Fe oxides; not continuously cemented.
sombric horizon
A subsurface accumulation of organic matter other than in spodic or natric horizons; not a buried surface horizon.
spodic horizon
A subsurface accumulation of aluminum (Al) with iron (Fe) and/or organic matter.
tsitelic horizon
A horizon with lateral accumulation of Fe, usually derived from Planosols and Stagnosols further upslope.
albic horizon
A light-coloured horizon with loss of coloured substances (e.g. oxides, organic matter) due to soil-forming processes.
cambic horizon
A horizon showing evidence of soil-forming processes, not meeting the criteria of diagnostic horizons that indicate stronger alteration or accumulation processes.
cohesic horizon
A horizon with massive or subangular blocky structure, restricted root penetration, normally free drainage, rich in kaolinite, and poor in organic matter.
ferralic horizon
A strongly weathered horizon dominated by kaolinites and oxides.
fragic horizon
A horizon with large soil aggregates where roots and percolating water penetrate the soil only in between these aggregates; not or only partially cemented.
nitic horizon
A horizon rich in clay minerals and Fe oxides, with moderate to strong structure and shiny soil aggregate surfaces.
panpaic horizon
A buried mineral surface horizon with a significant content of organic matter.
protovertic horizon
A horizon influenced by swelling and shrinking clay minerals.
vertic horizon
A horizon dominated by swelling and shrinking clay minerals.
takyric properties
Fine-textured surface crust with a platy or massive structure; under arid conditions in periodically flooded soils.
yermic properties
A combination of desert features: desert pavement, varnishing, ventifacts, vesicular pores, and platy structure.
abrupt textural difference
A very sharp increase in clay content within a limited depth range.
albeluvic glossae
Interfingering of coarser-textured and lighter-coloured material into an argic horizon forming vertically continuous tongues.
lithic discontinuity
Differences in parent material.
retic properties
Interfingering of coarser-textured and lighter-coloured material into an argic or natric horizon.
andic properties
Short-range-order minerals and/or organo-metallic complexes.
anthric properties
Applying to soils with mollic or umbric horizons, if the mollic or umbric horizon is created or substantially transformed by humans.
continuous rock
Consolidated material excluding cemented pedogenic horizons.
gleyic properties
Saturated with flowing or upwards moving groundwater (or upwards moving gases), permanently or long enough for reducing conditions to occur.
protocalcic properties
Carbonates derived from the soil solution and precipitated in the soil, less pronounced than in calcic or petrocalcic horizons.
protogypsic properties
Gypsum derived from the soil solution and precipitated in the soil, less pronounced than in gypsic or petrogypsic horizons.
reducing conditions
Low redox potential (rH value) and/or presence of sulfide, methane, or reduced iron (Fe).
shrink-swell cracks
Cracks that open and close due to the swelling and shrinking of clay minerals.
sideralic properties
Properties indicating relatively low cation exchange capacity (CEC).
stagnic properties
Saturated with surface water (or intruding liquids), at least temporarily, long enough for reducing conditions to occur.
vitric properties
Properties indicating ≥ 5% (by grain count) of volcanic glasses and related materials, containing a limited amount of short-range-order minerals and/or organo-metallic complexes.
mineral material
< 20% soil organic carbon and < 35% (by volume) organic artefacts.
mulmic material
Material developed from water-saturated organic material after drainage; 8 - 20% soil organic carbon.
organic material
Material with ≥ 20% soil organic carbon.
organotechnic material
Material with < 20% soil organic carbon and ≥ 35% (by volume) organic artefacts.
soil organic carbon
Organic carbon that does not meet the diagnostic criteria of artefacts.
claric material
Light-coloured fine earth, expressed by high Munsell value and low chroma.
artefacts
Materials created, substantially modified, or brought to the surface by humans; no subsequent substantial change of chemical or mineralogical properties.
technic material
Hard material that is consolidated and relatively continuous, resulting from an industrial process.
aeolic material
Material sedimented by wind.
calcaric material
Material with ≥ 2% calcium carbonate equivalent, at least partially inherited from the parent material.
dolomitic material
Material with ≥ 2% of a mineral that has a ratio of CaCO3/MgCO3 < 1.5.
fluvic material
Material from fluviatile, marine, or lacustrine deposits with evident stratification.
gypsiric material
Material with ≥ 5% gypsum, at least partially inherited from the parent material.
hypersulfidic material
Material containing sulfides and capable of severe acidification.
hyposulfidic material
Material containing sulfides and not capable of severe acidification.
limnic material
Material deposited in water by precipitation (possibly with sedimentation), or derived from algae or aquatic plants with subsequent transport or modification by aquatic animals or microorganisms.
ornithogenic material
Material from excrements or remnants of birds or bird activity.
solimovic material
A heterogeneous mixture that has moved down a slope, suspended in water; dominated by material that underwent soil formation at its original place.
tephric material
Material with ≥ 30% (by grain count) volcanic glass and related materials.
