Reference soil China 20: Ferralsol

CN020

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)

Very deep, well drained, yellowish red coarse sandy loam. The deeper subsoil is strongly mottled. Soil colour of the BA horizon is slightly darker. It is assumed that the overlying topsoil is strongly influenced by human influences. GENERAL LANDFORM: the east coastal erosion terrace in the granite consist of an undulating to nearly flat landscape. Hilly parts alternate with large flat valley plains merging towards the coastal plains / GENERAL SOIL INFORMATION: the soils developed in the granite hills are not very deep, generally between 0.5 to 1.5 meter. The granite rock is weathered to great depth (> 10 meter).The deeper subsoils frequently show strong mottling probably caused by past high groundwater levels ('pseudo-plinthite'?). 10 km north of the site the upper half of the soil consists of 50% or more coarse ironstone gravel overlying the weathered granite saprolite. It is not clear if the ironstone gravel is the result of in situ soil forming processes, or results from deposition (alluvial/colluvial processes) / ANALYTICAL DATA: there is a large difference in field texture and particle size distribution determined in the laboratory: Ap loamy coarse sand (field) sandy clay loam (lab) AB sandy loam (field) sandy clay (lab) BA sandy loam (field) sandy clay (lab) Bw sandy loam (field) clay (lab) BC(g) loamy coarse sand (field) sandy clay loam (lab) CB(g) loamy coarse sand (field) sandy clay loam (lab)

Classification

Orthic Ferralsol

WRB 2006		WRB 1998
Acric-Vetic Ferralsol (Humic Alumic)		Alumi-Acric Ferralsol (Hyperdystric)
6- 140 cm	f erralic horizon	0-6 cm	ochric horizon
		6-140 cm	ferralic horizon
FAO-UNESCO-ISRIC 1988		FAO-UNESCO-ISRIC 1974
Veti-Ferralic Cambisol
0-6 cm	ochric A horizon	0-6 cm	ochric A horizon
-	argic B horizon	6-200 cm	a oxic B horizon
-	ochric A horizon
	ferralic

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

Other classification

USDA-NRCS (1999	Typic Hapludox
USDA-SCS (1975)	Typic Haplorthox ustic fine kaolinitic isohyperthermic

Location:

Hainan, Wan-Ning County, Xing-Long town, E of Tai Yang River

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Physical characteristics

Particle size distribution

Depth (cm)	Clay % weight/weight	coarse sand % weight/weight	coarse silt % weight/weight	fine sand % weight/weight	fine silt % weight/weight	Gravel % volume/volume	medium sand % weight/weight	Total sand % weight/weight	Total silt % weight/weight	very coarse sand % weight/weight	very fine sand % weight/weight
0-6	32.7	11.9	1.2	7.4	10.1	-	7.1	56	11.3	27.3	2.3
6-30	37.0	11.1	1.3	6.7	10.2	-	6.3	51.5	11.5	24.2	3.2
30-45	36.7	9.5	2.4	6.6	8.6	-	5.8	52.2	11.0	28.1	2.2
45-110	44.8	7.7	4.4	4.3	8.5	-	4.2	42.4	12.9	23.2	3.0
110-140	31.5	8.5	7.2	7.1	15.5	-	5.2	45.9	22.7	22.0	3.1
140-180	30.0	9.8	5.5	7.6	16.3	-	5.7	48.2	21.8	20.5	4.6

Other physical data

Depth (cm)	Bulk density kg/dm³	Clay % weight/weight	COLE cm/cm	Spec. Surf. Area m²/g	Water disp. clay %
0-6	-	32.7	-	-	19.0
6-30	-	37.0	-	-	7.4
30-45	-	36.7	-	-	6.6
45-110	-	44.8	-	-	2.3
110-140	-	31.5	-	-	2.9
140-180	-	30.0	-	-	5.5

Chemical characteristics

Depth (cm)	C % weight/weight	Ca cmol(c)/kg	CaCO3 % weight/weight	C / N unitless	EC 1: 2.5 mS/cm	Exch. Acid cmol(c)/kg	Exch. Al cmol(c)/kg	K cmol(c)/kg	Mg cmol(c)/kg	N %	Na cmol(c)/kg	pH H2O unitless	pHKCl unitless	Sum Cations cmol(c)/kg
0-6	1.87	0.2	-	10	0.16	1.7	1.1	0.2	0.3	0.18	0.1	3.9	3.9	0.8
6-30	1.16	0.0	-	12	0.07	1.7	1.4	0.1	0.0	0.10	0.1	4.0	4.0	0.2
30-45	0.87	0.0	-	10	0.04	1.6	1.1	0.1	0.0	0.09	0.1	4.1	4.0	0.2
45-110	0.44	0.2	-	6	0.04	1.8	1.6	0.0	0.0	0.07	0.0	4.1	4.0	0.2
110-140	0.13	1.6	-	4	0.04	1.8	1.6	0.0	0.0	0.03	0.1	4.2	4.0	1.7
140-180	0.14	1.4	-	5	0.04	1.9	1.6	0.0	0.0	0.03	0.0	4.2	4.0	1.4

Depth (cm)	Al sat. %	Base sat. %	CEC clay cmol(c)/kg	CEC org cmol(c)/kg	CEC soil cmol(c)/kg	ECEC cmol(c)/kg	ESP %
0-6	21	15	16	6.5	5.3	-	2
6-30	40	6	9	4.1	3.5	-	3
30-45	30	5	10	3.0	3.7	-	3
45-110	57	7	6	1.5	2.8	-	0
110-140	41	44	12	0.5	3.9	-	3
140-180	57	50	9	0.5	2.8	-	0

Depth (cm)	Al d % weight/weight	Al o % weight/weight	Al p % weight/weight	C p % weight/weight	Fe d % weight/weight	Fe o % weight/weight	Fe p % weight/weight	ODOE unitless	pH NaF unitless	P Retention %	Si o % weight/weight
0-6	0.30	-	-	-	1.80	-	-	-	-	-	-
6-30	0.30	-	-	-	1.80	-	-	-	-	-	-
30-45	0.40	-	-	-	2.00	-	-	-	-	-	-
45-110	0.40	-	-	-	2.60	-	-	-	-	-	-
110-140	0.20	-	-	-	2.00	-	-	-	-	-	-
140-180	0.30	-	-	-	2.00	-	-	-	-	-	-

Depth (cm)	CaSO4.2H2O %	P Bray mg/kg	pH CaCl2 unitless	P Olsen mg/kg
0-6	-	1.9	-	-
6-30	-	2.9	-	-
30-45	-	1.1	-	-
45-110	-	0.3	-	-
110-140	-	0.8	-	-
140-180	-	0.9	-	-

Clay mineralogy

Depth (cm)	Chlorite unitless	Feldspar unitless	Gibbsite unitless	Goethite unitless	Halloysite unitless	Hematite unitless	Kaolinite unitless	Mica / illite unitless	Mixed-layer unitless	Quartz unitless	Smec unitless	Vermiculite unitless
0-6	weak	-	weak	medium to strong	-	-	very strong	-	weak	-	-	-
6-30	weak	-	weak	medium to strong	-	-	very strong	-	weak	-	-	-
30-45	weak	-	weak	medium to strong	-	-	very strong	-	weak	-	-	-
45-110	weak	-	weak	medium to strong	-	-	very strong	-	weak	-	-	-
110-140	weak	-	weak	medium to strong	-	-	very strong	-	weak	-	-	-
140-180	-	-	weak	medium to strong	-	-	very strong	-	very weak	-	-	-

Profile description

Ap 0-6 cm	dark brown (7.5YR 3/4, moist)loamy coarse sand,structureless parting to weak parting to crumb,loose loose non sticky non plastic,clear smooth boundary to,
AB 6-30 cm	strong brown (7.5YR 5/6, moist)sandy loam,weakly coherent porous massive parting to weak medium subangular blocky,slightly hard very friable slightly sticky slightly plastic,many fine interstitial pores,clear smooth boundary to,
BA 30-45 cm	strong brown (7.5YR 4/6, moist)sandy loam,weakly coherent porous massive parting to weak medium subangular blocky,very friable slightly sticky slightly plastic,many fine interstitial pores,clear smooth boundary to,
Bw 45-110 cm	yellowish brown (10YR 5/8, moist)sandy loam,weakly coherent porous massive,very friable slightly sticky slightly plastic,many fine interstitial pores,diffuse smooth boundary to,
BC(g) 110-140 cm	yellowish brown (10YR 5/8, moist)loamy coarse sand,WV porous massive,very friable non sticky non plastic,few coarse distinct mottles (10YR 6/8),many fine interstitial pores,diffuse smooth boundary to,
CB(g) 140-200 cm	yellowish brown (10YR 5/8, moist)loamy coarse sand,weakly coherent porous massive,very friable non sticky non plastic,many coarse prominent mottles (10YR 6/8),many fine interstitial pores,

Remarks on Parent Materials	granite
General characterization of the status of weathering of solid rock	slightly
Kind 1 (parent material) ; Parker (eds), 1984	coarse-grained acid igneous rock
Texture of parent material	loamy
Mode of accumulation or deposition of parent material	residual material
Soil Depth	200cm

Remarks on Land Use / Vegetation	Former land use rubber trees
Land use or vegetation in the immediate vicinity of the site	fallow

Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plain
Altitude	40m
Physiographic position of the site	crest
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating
Physiographic Unit	low, broad interfluve (hill)
Slope	2%
Form of the slope surrounding the site	convex

Moist From - To	20-200cm
Kind of ground water table (USDA, 1979)	no groundwater table observed
Drainage class ; FAO (2006) - Guidelines for soil description	well
Flooding frequency (FAO, 1986)	never
Dry From - To	0-20cm

Surface cracking	no cracks observed
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
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

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Reference soil China 20: Ferralsol

Characteristics

Classification