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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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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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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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Endoskeleti-Vertic Cambisol(Eutric and Chromic) \Eutri-Vertic Cambisol

(Chromic), Italy


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Calcaric Cambisol, Mexico

0 5 10 15 20

% CaCO3

75-100cm

50-75cm

25-50cm

0-25cm


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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

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