Reference soil China 26: Cambisol

CN026

Cambisols occur mainly in the temperate and boreal regions of the world, where the soil’s parent material is still young or where low temperatures slow down the processes of soil formation. Characteristics Soils having either a cambic horizon (a horizon showing evidence of alteration with respect to the underlying material), or a mollic horizon overlying a subsoil, which has a base saturation of less than 50 percent in some part within 100 cm from the soil surface, or one of the following diagnostic horizons within the specified depth: an andic, vertic, or vitric horizon starting between 25 and 100 cm; a (petro-)plinthic or salic horizon starting between 50 and 100 cm, in absence of loamy sand or coarser textures above these horizons.

Distribution of Cambisols

Reference soil CN026: Cambisol

PROFILE DESCRIPTION: Moderately deep, well drained, brown slightly stony loam derived from granite. The dark (yellowish) brown topsoil is high to very high in organic carbon and has a moderately developed crumb structure. The subsoil is only weakly structured. Base saturation is very low and the soil reaction is strongly acid throughout. SLOPE PROCESSES: extremely heavy rainfall in June 1992 (about 1000 mm in 10 days) provoked several landslides in this physiographic unit / SOIL DEPTH: profile is located on the somewhat less steeper upper part of the V-shaped valley slope, hence soils are expected to be somewhat deeper than elsewhere. Lower on the slope the soils are shallower. The summit of the range has many outcrops. Slide nos. of the ISRIC collection: 13897-13904 (landscape, profile, profile details, vegetation).

WRB 2006:

WRB 1998:

Endoleptic Cambisol(Alumic Humic Skeletic)

Ferrali- Endoleptic Cambisol(Hyperdystric)

10-35 cm	cambic horizon
property	continuous rock

0-10 cm	ochric horizon
10-35 cm	cambic horizon
property	continuous hard rock

FAO-UNESCO-ISRIC 1988:

FAO-UNESCO 1974:

Humi-

Dystric Cambisol

lithic phase

Dystric Cambisol

0-10 cm	ochric A horizon
10-35 cm	cambic B horizon
property	continuous hard rock
property	strongly humic

0-10 cm	ochric A horizon
10-80 cm	cambic B horizon

Other classification

USDA-SCS (1975)

Dystrochrept

coarse-loamy

mixed

mesic

Classification (other)	Para-yellow soil; Acidi-Udic Cambosol
Common name	Acid brown earth

Location:

Yanshan, Wuyi Mountains Natural Reserve

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Physical

Particle size distribution:

Depth (cm)		Gravel (%)	Very Coarse Sand (%)	Coarse Sand (%)	Medium Sand (%)	Fine Sand (%)	Very Fine Sand (%)	Total Sand (%)	Coarse Silt (%)	Fine Silt (%)	Total Silt (%)	Clay (%)
0-10	:	-	5.3	7.6	6.1	4.7	3.0	-	5.2	29.3	34.5	38.9
10-25	:	-	5.2	7.6	6.3	5.2	2.2	-	6.0	31.7	37.7	35.7
25-80	:	-	9.3	14.7	10.8	9.4	5.0	-	6.4	21.8	28.2	22.6
80-100	:	-	7.5	15.7	15.0	16.7	5.7	-	9.4	16.5	25.9	13.4

Chemical characteristics:

Depth (cm)		pH H2O	pH KCl	EC 1 : 2.5 (mS/cm)	CaCO3 (%)	Org. C (%)	Org. N (%)	C / N	Exch. Acid (cmol/kg)	Exch. Al (cmol/kg)	Ca (cmol/kg)	Mg (cmol/kg)	K (cmol/kg)	Sum Cations (cmol/kg)
0-10	:	4.1	3.8	0.16	-	6.03	-	-	-	-	0.2	0.3	0.2	-
10-25	:	4.1	4.1	0.07	-	4.00	-	-	-	-	0.0	0.0	0.1	-
25-80	:	4.5	4.3	0.02	-	0.95	-	-	-	-	0.0	0.0	0.1	-
80-100	:	4.9	4.3	0.01	-	0.03	-	-	-	-	0.2	0.0	0.6	-

Depth (cm)		CEC Soil (cmol/kg)	CEC Clay (cmol/kg)	CEC Org (cmol/kg)	ECEC (cmol/kg)	Base sat. (%)	Al sat. (%)
0-10	:	19.7	-	21.1	-	-	-
10-25	:	12.1	-	14.0	-	-	-
25-80	:	5.1	-	3.3	-	-	-
80-100	:	3.0	-	0.1	-	-	-

Depth (cm)		pH NaF	P Retention (%)	ODOE	Melanic Index	Fe o (wt%)	Al o (wt%)	Si o (wt%)	Fe d (wt%)	Al d (wt%)	Fe p (wt%)	Al p (wt%)	C p (wt%)
0-10	:	-	-	-	-	-	-	-	1.60	0.40	-	-	-
10-25	:	-	-	-	-	-	-	-	1.60	0.60	-	-	-
25-80	:	-	-	-	-	-	-	-	0.70	0.30	-	-	-
80-100	:	-	-	-	-	-	-	-	0.30	0.10	-	-	-

Depth (cm)		P Olsen (mg/kg)	P Bray (mg/kg)	pH CaCl2	CaSO4.2H2O (%)
0-10	:	-	2.3	-	-
10-25	:	-	0.9	-	-
25-80	:	-	4.0	-	-
80-100	:	-	2.0	-	-

Clay mineralogy:

Depth (cm)		Kaolinite	Mica / illite	Vermiculite	Chlorite	Smec	Halloysite	Mixed layer	Quar	Feldspar	Gibbsite	Goethite	Hematite
0-10	:	medium to strong	weak	-	medium to strong	-	-	-	weak	-	medium to strong	-	-
10-25	:	medium to strong	weak	-	medium to strong	-	-	-	weak	-	medium to strong	-	-
25-80	:	medium to strong	medium to strong	-	medium to strong	-	-	-	weak	-	medium to strong	-	-
80-100	:	medium to strong	medium to strong	-	-	-	-	-	very weak	-	weak	-	-

Profile description:

Ah 0-10 cm	dark brown (10YR 3/3, moist), sandy clay loam slightly stony leaves slightly, moderate medium crumb, very fine slightly sticky slightly plastic, many fine continuous exped and inped vesicular random pores and common continuous exped vesicular random pores highly porous (>60 vol%), very few medium gravel weathered granite fragments, frequent pedotubules, clear wavy boundary to,
B 10-35 cm	dark yellowish brown (10YR 4/6, moist), loam slightly stony, weak to moderate medium subangular blocky, very friable sticky plastic, common fine continuous exped and inped vesicular random pores and few continuous exped vesicular random pores moderately porous (40-60 vol%), few medium gravel strongly weathered granite few coarse gravel strongly weathered granite fragments, frequent pedotubules, gradual irregular boundary to,
BC 35-80 cm	brown (7.5YR 5/4, moist), loam, very weak medium subangular blocky, very friable sticky plastic, common fine continuous exped and inped vesicular random pores moderately porous (40-60 vol%), dominant coarse gravel and stones strongly weathered granite fragments, few pedotubules, abrupt smooth boundary to,
R 80-100 cm	dominant coarse gravel and stones strongly weathered rotten granite fragments.

The main parent rock/ material over which the soil has been formed (1st entry)	coarse-grained acid igneous rock
Mode of Accumulation or deposition of parent material (1st entry)	residual material
Texture of parent material (1st entry)	sandy clay
Weathering status of solid rock (1st entry)	high
Resistance against weathering (solid rock) (1st entry)	very high
Remarks on Parent Materials	rotten granite >2m
Soil Depth	80cm

Occurrence of soil aggradation	absent
Slope Stability	locally unstable

Current land use at the site	(semi-)natural vegetation
Main type of irrigation	no irrigation
Rotation scheme	crop rotation scheme not relevant
Vegetation Type;The natural vegetation at the site	semi-deciduous forest
Status of vegetation	primary
Remarks on Land Use / Vegetation	Vegetation: Tsuga tchekiangensis, bamboo undergrowth

The altitude of the soil profile relative to mean sea level, specified in meters	1800 m asl
Regional landform	mountain
Topography of the surrounding country	mountainous
Physiographic Unit in the immediate surrounding of the site	upper slope of V-shaped valley
The slope refers to the inclination of the land immediately surrounding the site. The measured or estimated slope angle is specified to the nearest per cent	45 %
The physiographic position of the site where the profile is located	upper slope
Form of the slope surrounding the site	straight
Slope Aspect of the site	north-east

Kind of groundwater table	no groundwater table observed
Runoff	medium
Flooding frequency	never
Estimated permeablity (class) of least permeable part of the profile	high
Drainage Class	well
Moist From - To	0-100cm

Rockiness	none
Stoniness	very few stones
Average size of stones	20
Cracks	no cracks observed
Slaking of aggregates by tillage, rainfall or frost	no surface slaking/crusting observed
Evidence of salt	non-saline
Evidence of alkali	non-alkaline

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Reference soil China 26: Cambisol

Reference soil CN026: Cambisol