files spar cam
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CAMBISOLS
Otto Spaargaren
ISRIC World SoilInformation
Wageningen
The Netherlands
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Definition of Cambisols
Soils that show soil formation by either:
Colour change compared to parent material Soil structure development
Leaching of carbonates
Formation of silicate clays andsesqui(hydr)oxides as result of weathering ofprimary minerals
But lack sufficient soil development toclassify for other RSGs
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Diagnostics of Cambisols
Cambisols have:
z A cambichorizon; or
z A mollichorizon overlying a subsoil with lowbase saturation within 100cm depth; or one ofthe following:
z An andic, verticor vitrichorizon starting
between 25 and 100cm below the surface; orz A plinthic, petroplinthic, salicor sulfuric
horizon starting between 50 and 100cm belowthe soil surface, in the absence of loamy sandor coarser material above these horizons
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Cambic horizon (1)
Results from incipient soil formation:
z
Texture sandy loam of finerz At least moderately developed soil
structure, and lacking original rock
structure in at least half of the volume ofthe horizon
z Evidence of alteration (stronger chroma,
redder hue, more clay than underlyinghorizon, removal of carbonates)
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Cambic horizon (2)
z Lacking the brittle consistence of thefragichorizon
z CEC > 16 cmol(+) kg-1; or
ECEC > 12 cmol(+) kg-1; or
10 percent weatherable minerals; or10 percent water-dispersible clay; and
z Thickness of 15cm or more
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Genesis of Cambisols
Main soil-forming factor is:
Time
Main soil-forming processes are:
Dissolution and removal of carbonates
Alteration of especially easy-weatherableprimary minerals such as mica and feldspar
Formation of silicate clay and precipitation ofiron(hydr)oxides
Aggregation to form soil structure
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Classification of Cambisols (1)
z Strong expression qualifier: thionic
z Intergrade qualifiers: andic, endosalic,ferralic, fluvic, gelic, gleyic, leptic, plinthic,vertic, and vitric
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Classification of Cambisols (2)
z Secondary characteristics qualifiers,related to defined diagnostic horizons,
properties or materials: aridic, calcaric,gelistagnic, gypsiric, humic, hyperochric,stagnic, takyric, and yermic
z Secondary characteristics qualifiers,not related to defined diagnostic horizons,properties or materials: chromic, dystric,
eutric, rhodic, skeletic, and sodic
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Classification of Cambisols (3)
z Haplic qualifier, where non of the aboveapplies: haplic
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Examples of Cambisols (1)
Humi-Endoleptic Cambisol(Dystric), China
0 10 20 30 40
80-100cm
35-80cm
10-35cm
0-10cm
% clay
Fe(d) g/kg%org C
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Examples of Cambisols (2)
Endoskeleti-Vertic Cambisol(Eutric and Chromic) \Eutri-Vertic Cambisol
(Chromic), Italy
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Examples of Cambisols (3)
Calcaric Cambisol, Mexico
0 5 10 15 20
% CaCO3
75-100cm
50-75cm
25-50cm
0-25cm
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Examples of Cambisols (4)
Hyperdystri-Ferralic Cambisol(Chromic), China
8182.590-120
5173.770-90
2208.840-70
3116.515-40
61115.30-15
% basesaturation
CEC claycmol(+)
CEC soilcmol(+)
Depth(cm)
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Distribution of Cambisols (1)
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Distribution of Cambisols (2)
One of the most widespread soils, coveringsome 1.57 billion ha or 12.5 % of the
Earths land surface, mainly in temperateand boreal regions, in desert regions,and in mountainous areas.
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Associated soils
Temperate and boreal regions: Fluvisolsand Gleysols in low-lying positions;Regosols, Podzols, Luvisols and
Umbrisols in upland areasDeserts: Regosols, Calcisols, Gypsisols,
Arenosols and Leptosols
Mountains: Leptosols, Regosols andUmbrisols
Tropical regions: Ferralsols, Acrisols and
Lixisols