Reference soil China 17: Ferralsol

CN017

Ferralsols occur in tropical and subtropical regions of the world, mainly on old and stable land surfaces.

Characteristics

Soils having a ferralic horizon (strongly weathered horizon with low-activity clays and very low amounts of weatherable minerals) between 25 and 200 cm from the soil surface. They lack a nitic horizon (a horizon with strongly developed, nut-shaped structure) and do not have a layer which fulfils the requirements of an argic horizon and which has, in the upper 30 cm, 10 percent or more water-dispersible clay.

Distribution of Ferralsols (rough estimation supplied by soilgrids)

Reference soil CN017: Ferralsols

PROFILE DESCRIPTION : Very deep, well drained, reddish brown sandy clay loam derived from granite. Soil structure is only weakly expressed. It is highly porous and well rooted, shows a strong biological activity and contains in the deeper subsoil weathered granite fragments. LAND USE AND VEGETATION: original vegetation is a deciduous tropical forest. Before 1963 secondary forest, in 1963 planting of rubber trees. Tree distance 6 x 3 meter. Fertilizer use: Urea and phosphorus. Yield is about 3 ton/ha/year. GENERAL SOIL INFORMATION: Soil map 1:500.000 indicates that CN017 is located in the largest map unit, i.e. Latosol derived from granite. This soil type covers the largest part of Hainan Island. Granite is the dominant parent rock of Hainan island. Field observations show that besides this reddish brown clayey soil, other variants exist. The soil varies from reddish brown clay to light greyish sandy loam/loamy sand. The greyish colour is caused by groundwater influence but probably also induced by a coarser, more acid granite type resulting in a sandy soil. No detailed maps were made available, but field observations in a transect from west to east show that both soil types appear to be representative for large areas. The soil is formed in an erosion terrace in granite. The altitude of the terrace is around 150 meter. The landscape has a plain-like appearance and consists of low, broad interfluves (hills). CN017 is located on an upper slope position of a broad, low hill, being representative for the larger part of the hill. On the lower slope, transitional to the valley, soil colours become more yellow and the subsoil strongly mottled. The soil has a high biological activity. Pores and cavities are made by termites (dominant), ants and worms. Spherical termite cavities occur having a diameter of about 5 to 6 cm and flat floors, with or without fungus gardens. Their density about 2/m2. Penetrometer readings in moist B-horizon, about 4 kg/cm2. Slides in the ISRIC collection: landscape, soil, rubber trees.

Classification

WRB 2006

WRB 1998

Acric-Geric- Ferralsol (Alumic)

Profondi-Vetic- Acrisol (Hyperdystric Chromic)

20-180 cm	ferralic horizon
-	geric

0-40 cm	ochric horizon
20-180 cm	ferralic horizon
-	geric

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Veti-Haplic Acrisol

Ferric Acrisol

0-40 cm	ochric A horizon
- cm	argic B horizon
- cm	ferralic B horizon
- cm	ochric A horizon

0-40 cm	ochric A horizon
20-155 cm	argillic B horizon

Local classification:	Haplic latosol; Hapli-Udic Ferralosol
Common name:	Red clay-leached soil

Other classification

USDA-NRCS (1999)	Typic Kandiudult
USDA-SCS (1975)	Typic Paleudult udic clayey kaolinitic isohyperthermic

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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	-	5.1	17.6	22.2	24.3	4.9	74.1	0.5	6.2	6.7	19.2
5-20	-	5.1	14.1	19.3	23.4	7.1	69	0.7	5.3	6.0	25.0
20-40	-	6.4	13.5	16.8	19.9	4.0	60.6	0.8	6.9	7.7	31.8
40-100	-	7.6	12.4	14.1	14.8	4.8	53.7	1.1	8.0	9.1	37.1
100-150	-	10.2	13.1	13.1	13.5	3.1	53	2.0	7.7	9.7	37.2
150-180	-	20.6	11.7	9.3	9.6	4.0	55.2	0.7	8.9	9.6	35.2

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
5-10	1.420	-	-	-	-
0-5	-	-	-	13.9	19.2
5-20	-	-	-	17.0	25.0
40-45	1.395	-	-	-	-
100-105	1.346	-	-	-	-
20-40	-	-	-	17.6	31.8
40-100	-	-	-	2.9	37.1
100-150	-	-	-	4.4	37.2
150-180	-	-	-	3.4	35.2

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
5-10	1.420	39.8	37.8	32.2	27.8	26.6	24.0	19.2	16.5
40-45	1.395	39.0	37.8	33.7	30.7	30.0	28.1	24.3	20.5
100-105	1.346	40.2	39.1	35.7	32.9	32.2	30.4	24.5	21.4

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	4.8	4.1	0.16	-	1.50	0.12	13	0.7	0.5	0.6	0.3	0.2	0.1	1.2
5-20	4.3	4.1	0.11	-	0.85	0.08	11	1.2	0.9	0.0	0.0	0.1	0.1	0.2
20-40	4.2	4.1	0.06	-	0.55	0.06	9	1.2	0.9	0.0	0.0	0.1	0.0	0.1
40-100	4.2	4.2	0.06	-	0.29	0.04	7	1.0	0.5	0.2	0.0	0.1	0.0	0.3
100-150	4.5	4.4	0.05	-	0.18	0.03	6	0.3	0	0.0	0.3	0.1	0.1	0.5
150-180	4.6	4.5	0.02	-	0.13	0.05	3	0.3	0	0.0	0.3	0.1	0.0	0.4

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	34	3.5	18	5.3	-	14	3
5-20	8	2.5	10	3.0	-	36	4
20-40	4	2.3	7	1.9	-	39	0
40-100	19	1.6	4	1.0	-	31	0
100-150	31	1.6	4	0.6	-	0	6
150-180	29	1.4	4	0.5	-	0	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	-	13	-	-	-	1.40	0.20	-	-	-	-
5-20	-	17	-	-	-	1.60	0.20	-	-	-	-
20-40	-	17	-	-	-	2.10	0.20	-	-	-	-
40-100	-	24	-	-	-	2.70	0.20	-	-	-	-
100-150	-	23	-	-	-	2.80	0.20	-	-	-	-
150-180	-	22	-	-	-	2.80	0.20	-	-	-	-

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	-	3.3	-	-	-	-	-	-	-
5-20	-	1.0	-	-	-	-	-	-	-
20-40	-	0.0	-	-	-	-	-	-	-
40-100	-	0.0	-	-	-	-	-	-	-
100-150	-	0.0	-	-	-	-	-	-	-
150-180	-	0.0	-	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-5	-	-	weak	weak	-	-	very strong	weak	-	-	-	-
5-20	-	-	weak	weak	-	-	very strong	weak	weak	-	-	-
20-40	-	-	weak	weak	-	-	very strong	weak	weak	-	-	-
40-100	-	-	weak	weak	-	-	very strong	weak	weak	-	-	-
100-150	-	-	weak	weak	-	-	very strong	weak	weak	-	-	-
150-180	-	-	weak	weak	-	-	very strong	-	-	-	-	-

Profile description

Ah 0-20 cm	reddish brown (2.5YR 4/4, dry) dark reddish brown (2.5YR 3/4, moist)sandy clay loam,weak fine subangular blocky,slightly hard friable slightly sticky slightly plastic,many very fine fine tubular random pores,gradual smooth boundary to,
Bw 40-155 cm	dark red (2.5YR 3/6, moist)(2.5YR 4/7, moist),sandy loam,sandy clay loam,weakly coherent porous massive to weak fine subangular blocky,weak fine subangular blocky,friable slightly sticky slightly plastic,friable slightly sticky slightly plastic,many very fine fine tubular random pores,many very fine fine tubular random pores,very frequent termite channels,very frequent termite channels,gradual smooth boundary to,gradual smooth boundary to,
155-175 cm	(2.5YR 4/7, moist)sandy loam,weakly coherent porous massive,friable non sticky non plastic,many very fine tubular random pores,frequent fine gravel strongly weathered granite fragments,

Kind 1 (parent material) ; Parker (eds), 1984	coarse-grained acid igneous rock
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	granite
Soil Depth	150cm
Texture of parent material	loamy
General characterization of the status of weathering of solid rock	highly

Major crops	rubber
Remarks on Land Use / Vegetation	VEGETATION: Original vegetation is deciduous tropical forest. Before 1963 secondary forest, in 1963 planting of rubber trees. LANDUSE: Tree distance 6 x 3 meter. Fertilizer use: Urea and phosphorus. Yield is about 3 ton/ha/year.
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	cut over
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	evergreen forest

Altitude	140m
Physiographic Unit	erosion terrace in granite
Physiographic position of the site	upper slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plain
Slope	2%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-50cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	50-155cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Surface cracking	no cracks observed
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none

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Reference soil China 17: Ferralsol

Characteristics

Reference soil CN017: Ferralsols

Classification