Reference soil China 28: Acrisol

CN028

Acrisols occur dominantly in the wetter parts of the tropics and subtropics and the warm temperate regions in relatively young landscapes.

Characteristics

Soils having an argic horizon (a subsurface horizon with distinct higher clay content than the overlying horizon), which has a cation exchange capacity of less than 24 cmolc per kg in some part, either starting within 100 cm from the soil surface, or within 200 cm from the soil surface if the argic horizon is overlain by loamy sand or coarser textures throughout. They have a base saturation (total amount of Ca, Mg, K and Na with respect to the cation exchange capacity) of less than 50 percent in the major part between 25 and 100 cm from the soil surface

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil CN028: Acrisols

PROFILE DESCRIPTION : Deep, well drained, colluvial yellowish red clay overlying red clay derived from in situ weathered granite. The two materials are separated from each other by a stoneline of about 20 cm thick. The soil shows moderately to strongly developed angular blocky structures. It is low in organic carbon and strongly acid throughout. PARENT MATERIAL: Depth of the stoneline in the road-cut varies with location. Sometimes rotten rock comes close to the surface. Here colluvium (stoneline) are absent. Slide nos. of the ISRIC collection: 13913-13916 (landscape, profile, profile details).

Classification

WRB 2006

WRB 1998

Cutanic- Acrisol (Ruptic Alumic Clayic)

Chromi-Hyperdystric- Acrisol

5-90 cm

argic horizon

0-5 cm	ochric horizon
5-90 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Alumi-Haplic Acrisol

Ferric Acrisol

0-5 cm	ochric A horizon
5-90 cm	argic B horizon
- cm	argic B horizon
- cm	ochric A horizon

0-5 cm	ochric A horizon
5-90 cm	argillic B horizon

Local classification:	Argillic red soil; Argi-Udic Ferrosol
Common name:	Acid red clay

Other classification

USDA-NRCS (1999)	Typic Hapludult
USDA-SCS (1975)	Typic Hapludult udic clayey kaolinitic mesic

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Physical characteristics

Particle size distribution

Depth (cm)	Gravel % v/v	very coarse sand % w/w	coarse sand % w/w	medium sand % w/w	fine sand % w/w	very fine sand % w/w	Total sand % w/w	coarse silt % w/w	fine silt % w/w	Total silt % w/w	Clay % w/w
0-5	-	3.6	4.2	10.3	10.7	3.7	32.5	8.5	13.9	22.4	45.2
15-40	-	5.2	4.2	7.9	6.5	2.7	26.5	4.8	14.5	19.3	54.4
50-60	-	5.6	5.8	9.0	9.5	3.9	33.8	9.8	15.5	25.3	40.9
70-85	-	4.9	4.2	7.5	6.6	3.8	27	7.8	8.0	15.8	57.1
90-110	-	6.3	7.9	15.8	12.3	3.1	45.4	4.9	11.5	16.4	38.3

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-5	0.848	-	-	22.4	45.2
15-40	-	-	-	2.1	54.4
15-20	1.220	-	-	-	-
50-60	-	-	-	2.6	40.9
90-95	1.231	-	-	-	-
70-85	-	-	-	0.0	57.1
90-110	-	-	-	0.5	38.3

Other physical data

Depth (cm)	Bulk density kg/dm³	pF 0 % v/v	pF 1.0 % v/v	pF 1.5 % v/v	pF 2.0 % v/v	pF 2.3 % v/v	pF 2.7 % v/v	pF 3.4 % v/v	pF 4.2 % v/v
0-5	0.848	52.0	43.4	36.8	31.8	31.3	27.6	23.3	19.7
15-20	1.220	48.4	45.8	41.8	38.3	37.9	35.7	34.8	27.3
90-95	1.231	48.2	44.9	40.7	37.3	36.8	34.9	31.8	28.2

Chemical data

Depth (cm)	pH H2O	pHKCl	EC 1: 2.5 dS/m	CaCO3 % w/w	C % w/w	N %	C / N	Exch. Acid cmol(c)/kg	Exch. Al cmol(c)/kg	Ca cmol(c)/kg	Mg cmol(c)/kg	K cmol(c)/kg	Na cmol(c)/kg	Sum Cations cmol(c)/kg
0-5	4.1	3.6	0.04	-	1.75	0.10	18	5.1	4.5	0.2	0.0	0.1	0.0	0.3
15-40	4.4	3.7	0.01	-	0.54	0.04	14	4.2	3.9	0.0	0.0	0.0	0.0	0
50-60	4.5	3.8	0.01	-	0.45	0.03	15	3.4	3.2	0.4	0.0	0.0	0.0	0.4
70-85	4.5	3.8	0.01	-	0.15	0.02	8	3.6	3.6	0.2	0.0	0.0	0.0	0.2
90-110	4.6	3.9	0.01	-	0.06	0.01	6	3.0	2.7	0.2	0.1	0.0	0.0	0.3

Depth (cm)	Base sat. %	CEC soil cmol(c)/kg	CEC clay cmol(c)/kg	CEC org cmol(c)/kg	ECEC cmol(c)/kg	Al sat. %	ESP %
0-5	3	11.0	24	6.1	-	41	0
15-40	0	8.7	16	1.9	-	45	0
50-60	6	6.7	16	1.6	-	48	0
70-85	1	15.1	26	0.5	-	24	0
90-110	5	6.6	17	0.2	-	41	0

Depth (cm)	pH NaF	P Retention %	ODOE	Al o % w/w	Si o % w/w	Fe d % w/w	Al d % w/w	Fe p % w/w	Al p % w/w	C p % w/w	Fe o % w/w
0-5	-	-	-	-	-	2.10	0.50	-	-	-	-
15-40	-	-	-	-	-	2.80	0.70	-	-	-	-
50-60	-	-	-	-	-	2.40	0.50	-	-	-	-
70-85	-	-	-	-	-	2.70	0.50	-	-	-	-
90-110	-	-	-	-	-	2.00	0.40	-	-	-	-

Depth (cm)	CaSO4.2H2O %	P Bray mg/kg	P Olsen mg/kg	pH CaCl2	clay_noncarbonate % w/w	clay_carbonate % w/w	phosphorus4 mg/kg	phosphorus1 mg/kg	total_sulfur % w/w
0-5	-	0.2	-	-	-	-	-	-	-
15-40	-	0.0	-	-	-	-	-	-	-
50-60	-	0.0	-	-	-	-	-	-	-
70-85	-	0.0	-	-	-	-	-	-	-
90-110	-	0.0	-	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-5	strong	-	-	weak	-	-	very strong	-	-	-	-	-
15-40	medium to strong	-	-	weak	-	-	very strong	-	-	-	-	-
50-60	medium to strong	-	-	weak	-	-	very strong	-	-	-	-	-
70-85	medium to strong	-	-	weak	-	-	very strong	-	-	-	-	-
90-110	medium to strong	-	-	weak	-	-	very strong	-	-	-	-	-

Profile description

Ah 0-5 cm	strong brown (7.5YR 4/6, moist)sandy clay,very weak fine and medium angular blocky,firm very sticky very plastic,few common fine very fine continuous random tubular random pores,no fragments,few pedotubules,clear smooth boundary to,
Bt1 5-45 cm	(10YR 4/8, moist)clay slightly gravelly,moderate medium angular blocky parting to strong fine angular blocky,firm very sticky very plastic,patchy thick clay on pedfaces cutans,few fine very fine continuous random tubular random pores,few fine gravel weathered quartz fragments,few pedotubules,clear smooth boundary to,
2Bt2 45-65 cm	yellowish brown (10YR 5/8, moist)clay very stony,weak to moderate medium angular blocky,firm very sticky very plastic,patchy thick clay on pedfaces cutans,few fine very fine continuous random tubular random pores,very frequent medium gravel weathered quartz fragments,few pedotubules,clear smooth boundary to,
2Bt3 65-90 cm	red (2.5YR 5/8, moist)clay slightly gravelly,strong medium and coarse angular blocky parting to strong fine angular blocky,very firm very sticky very plastic,broken moderately thick clay on pedfaces cutans,few very fine continuous random tubular random pores,few fine gravel weathered quartz fragments,few pedotubules,abrupt irregular boundary to,
2BC 90-130 cm	red (2.5YR 5/8, moist)clay slightly stony,moderate medium and coarse angular blocky,firm very sticky very plastic,patchy thin clay on pedfaces cutans,few very fine continuous random tubular random pores,frequent medium gravel strongly weathered granite few medium gravel weathered quartz fragments,few pedotubules,

Depth1	45cm
Kind 1 (parent material) ; Parker (eds), 1984	coarse-grained acid igneous rock
Kind 2 (parent material) (second entry); Parker (eds), 1984	coarse-grained acid igneous rock
Mode of accumulation or deposition of parent material	colluvial
Mode of accumulation or deposition of parent material (second entry)	residual material
Remarks on Parent Materials	colluvium/stoneline
Soil Depth	90cm
Texture of parent material	sandy clay
Texture of parent material (second entry)	sandy clay

Occurrence of soil aggradation (McDonald et al., 1984)	not apparent
Intensity of the soil erosion type	slight
Soil erosion type	gully
Slope stability	locally unstable

Major crops	tea
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	no irrigation
Land use or vegetation in the immediate vicinity of the site	low level arable farming
Remarks on Land Use / Vegetation	LANDUSE: Oil-tea is grown with few inputs
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	degraded
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	shrub

Altitude	250m
Physiographic Unit	crest of lower part mountains
Physiographic position of the site	crest
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	mountain
Slope	40%
Slope Aspect	north
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	mountainous

Drainage class ; FAO (2006) - Guidelines for soil description	well
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-130cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	rapid

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Average size of stone	5
Surface cracking	no cracks observed
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Microrelief Height: variation in height	50
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	terracettes
Microrelief pattern	linear
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Shape of stones (on average)	angular irregular
Surface stoniness class (FAO (2006) - Guidelines for soil description)	fairly stony

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Reference soil China 28: Acrisol

Characteristics

Reference soil CN028: Acrisols

Classification