Reference soil China 04: Ferralsol

CN004

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 CN004: Ferralsols

Very deep, well drained, red silty clay loam derived from early Quaternary alluvial deposits. The topsoil is low in organic carbon and has a weak to moderate subangular blocky structure. The subsoil has subangular blocky to prismatic structures, tending to become "nut-shaped" between 39 and 113cm depth. The soil is very low in nutrients and has an acid to strongly acid soil reaction throughout. The amount of exchangeable aluminium is high. PARENT MATERIAL: the alluvial deposits in this region are underlain by purple rocks; locally layers of rounded gravel occur in the Red Earths of Changsha, mainly consisting of slightly weathered quartz / HYDROLOGY: infiltration is estimated at 10-50 cm/day / SURFACE DRAINAGE: coarse dendritic; in the lower reaches controlled by ditches for irrigating paddy fields / HUMAN INFLUENCES: locally levelling has taken place for vegetable growing / SOIL FAUNA: ants, beetles, worms, possibly also snakes.

Classification

WRB 2006

WRB 1998

Haplic- Ferralsol (Alumic Siltic)

Chromi-Hyperferralic- Cambisol (Hyperdystric)

6-150 cm

ferralic horizon

0-25 cm	ochric horizon
6-150 cm	ferralic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Alumi-Ferralic Cambisol

Orthic Ferralsol

0-25 cm	ochric A horizon
- cm	cambic B horizon
- cm	ochric A horizon
-	ferralic

0-25 cm	ochric A horizon
6-150 cm	oxic B horizon
-	ferralic

Local classification:	Haplic latored soil; Hapli-Udic Ferralosol
Common name:	Acid red earth

Other classification

USDA-SCS (1975)

Dystrochrept udic fine mixed thermic

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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
0-6	-	0.2	0.7	1.2	2.0	5.5	9.6	13.1	38.0	51.1	39.3
6-25	-	0.2	0.8	1.0	1.6	4.6	8.2	13.0	39.5	52.5	39.3
25-39	-	0.3	0.8	1.0	1.6	5.3	9	11.7	42.2	53.9	37.1
39-60	-	0.1	0.7	0.9	1.5	4.9	8.1	10.6	40.3	50.9	41.0
60-80	-	0.1	0.6	0.8	1.6	4.5	7.6	13.1	41.2	54.3	38.2
80-113	-	0.1	0.4	0.7	1.2	3.5	5.9	13.0	42.3	55.3	38.8
113-130	-	0.4	0.8	1.0	1.7	5.9	9.8	12.9	39.7	52.6	37.5
130-150	-	0.3	0.9	1.1	1.9	6.6	10.8	14.3	38.1	52.4	36.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-6	-	-	-	20.4	39.3
1-6	1.346	-	-	-	-
6-25	-	-	-	2.0	39.3
12-17	1.406	-	-	-	-
31-36	1.434	-	-	-	-
25-39	-	-	-	0.0	37.1
47-52	1.525	-	-	-	-
39-60	-	-	-	0.0	41.0
95-102	1.596	-	-	-	-
60-80	-	-	-	0.5	38.2
80-113	-	50	-	1.5	38.8
113-130	-	-	-	1.0	37.5
130-150	-	48	-	1.0	36.8

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
1-6	1.346	46.3	43.8	39.5	33.6	32.0	28.4	23.3	20.3
12-17	1.406	45.2	44.3	40.5	33.9	32.7	29.6	24.0	21.3
31-36	1.434	43.8	43.0	39.4	34.0	32.8	30.4	24.4	21.4
47-52	1.525	41.8	41.3	38.9	34.9	34.1	32.1	26.9	24.2
95-102	1.596	39.7	39.2	37.1	34.1	33.1	32.1	28.0	24.2

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
0-6	4.9	3.9	0.04	-	1.20	0.09	13	3.4	3.4	0.4	0.1	0.2	0.0	0.7
6-25	4.9	3.9	0.03	-	0.55	0.06	9	3.3	3.2	0.0	0.1	0.1	0.0	0.2
25-39	5.0	3.9	0.01	-	0.16	-	-	3.2	3.1	0.0	0.1	0.1	0.0	0.2
39-60	5.1	3.9	0.01	-	0.13	-	-	3.4	3.3	0.0	0.1	0.1	0.0	0.2
60-80	5.1	3.9	0.01	-	0.11	-	-	3.3	3.2	0.0	0.1	0.1	0.0	0.2
80-113	5.1	3.9	0.02	-	0.11	-	-	3.3	3.3	0.4	0.1	0.1	0.0	0.6
113-130	5.0	3.9	0.01	-	-	-	-	3.5	3.4	0.4	0.1	0.1	0.0	0.6
130-150	5.0	3.8	0.01	-	-	-	-	3.8	3.6	0.0	0.1	0.1	0.0	0.2

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 %
0-6	10	7.1	18	4.2	-	48	0
6-25	4	5.5	14	1.9	-	58	0
25-39	4	4.6	12	0.6	-	67	0
39-60	4	5.1	12	0.5	-	65	0
60-80	4	5.3	14	0.4	-	60	0
80-113	11	5.3	14	0.4	-	62	0
113-130	11	5.5	15	-	-	62	0
130-150	4	5.7	15	-	-	63	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
0-6	-	-	-	0.13	0.02	2.42	0.40	0.37	0.13	-	0.12
6-25	-	-	-	0.14	0.03	2.44	0.46	0.27	0.10	-	0.15
25-39	-	-	-	0.13	0.02	2.42	0.44	0.05	0.06	-	0.16
39-60	-	-	-	0.15	0.03	2.47	0.46	0.04	0.06	-	0.17
60-80	-	-	-	0.16	0.04	2.53	0.49	0.02	0.05	-	0.18
80-113	-	-	-	0.14	0.03	2.42	0.45	0.02	0.05	-	0.17
113-130	-	-	-	0.10	0.05	2.44	0.45	0.04	0.06	-	0.13
130-150	-	-	-	0.10	0.04	2.57	0.45	0.04	0.06	-	0.09

Elemental composition of the clay

Depth (cm)	SiO2 % w/w	Al2O3 % w/w	Fe2O3 % w/w	CaO % w/w	MgO % w/w	K2O % w/w	Na2O % w/w	TiO2 % w/w
80-113	46.3	27.6	10.3	0.05	1.14	2.76	-	1.25
130-150	46.5	28.0	10.7	0.04	1.15	2.72	-	1.36

Depth (cm)	MnO2 % w/w	P2O5 % w/w	Ign.Loss clay % w/w	Total Clay % w/w	SiO2/Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol	Al2O3/Fe2O3 mol/mol
80-113	0.10	0.11	9.3	98.9	2.9	12.0	2.3	4.2
130-150	0.06	0.10	9.4	100.0	2.8	11.6	2.3	4.1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-6	-	-	-	medium to strong	-	-	medium to strong	medium to strong	medium to strong	very weak	-	-
6-25	-	-	-	medium to strong	-	-	medium to strong	medium to strong	medium to strong	very weak	-	-
25-39	-	-	-	medium to strong	-	-	medium to strong	medium to strong	medium to strong	very weak	-	-
39-60	-	-	-	medium to strong	-	-	medium to strong	medium to strong	medium to strong	very weak	-	-
60-80	-	-	-	medium to strong	-	-	medium to strong	medium to strong	medium to strong	very weak	-	-
80-113	-	-	-	medium to strong	-	-	medium to strong	medium to strong	weak	very weak	-	-
113-130	-	-	-	medium to strong	-	-	medium to strong	weak	medium to strong	very weak	-	-
130-150	-	-	-	medium to strong	-	-	medium to strong	medium to strong	medium to strong	very weak	-	-

Profile description

Ah 0-6 cm	red (2.5YR 4/8, moist)clay loam,weak very fine and fine subangular blocky,very friable,common very fine discontinuous exped interstitial pores and common discontinuous exped tubular pores,abrupt smooth boundary to,
6-25 cm	red (2.5YR 4/8, moist)clay loam,moderate fine and medium subangular blocky,friable,patchy thin clay and sesquioxide cutans,common very fine discontinuous inped tubular pores,clear smooth boundary to,
Bt1 25-39 cm	red (2.5YR 4/8, moist)clay,moderate fine and medium subangular blocky,friable,broken moderately thick clay and sesquioxide cutans,common very fine fine continuous inped tubular pores and common fine discontinuous inped tubular pores,clear smooth boundary to,
Bt2 39-80 cm	red (2.5YR 5/8, moist)clay,moderate fine and medium prismatic,friable,few fine prominent sharp mottles (10YR 7/8),continuous moderately thick clay and sesquioxide cutans,common very fine discontinuous inped tubular pores,very few small spherical soft manganiferous concretions,diffuse smooth boundary to,
Bt3 80-113 cm	red (2.5YR 4/8, moist)red (2.5YR 5/8, moist),clay,clay,moderate fine and medium prismatic,moderate fine and medium subangular blocky,friable,firm,few fine prominent sharp mottles (10YR 7/8),few fine prominent sharp mottles (10YR 7/8),continuous moderately thick clay and sesquioxide cutans,broken moderately thick clay and sesquioxide cutans,few very fine discontinuous inped tubular pores,few very fine discontinuous inped tubular pores,very few small spherical soft manganiferous concretions,very few small spherical soft manganiferous concretions,diffuse smooth boundary to,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Soil Depth	180cm
Texture of parent material	clayey

Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	levelling
Land use or vegetation in the immediate vicinity of the site	afforestation
Remarks on Land Use / Vegetation	VEGETATION: Young pine trees with grass and herb

Altitude	40m
Physiographic Unit	footslope of hill
Physiographic position of the site	lower slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	alluvial plain
Slope	6%
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
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-150cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium

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 04: Ferralsol

Characteristics

Reference soil CN004: Ferralsols

Classification