Reference soil United States of America 09: Ferralsol

US009

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 US009: Ferralsols

Profile description: AB: dry colour also 2.5YR 3/6; Bt1: moist colours 10R 3/3, 3/4; Bt2: moist colours 10R 3/3, 3/4;

Classification

WRB 2014

Ferralsol

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Lixi-Rhodic Ferralsol

Rhodic Ferralsol

- cm	ferralic B horizon
- cm	ochric A horizon
-	nitic

- cm	ochric A horizon
- cm	oxic B horizon

Local classification:	Wahiawa Series

Other classification

USDA-NRCS (1999)	Rhodic Eutrustox
USDA-SCS (1975)	Rhodic Eutrustox ustic very fine kaolinitic isohyperthermic

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
0-14	-	0.6	0.7	0.5	0.6	0.3	2.7	6	22.9	28.9	68.4
14-30	-	0.4	0.7	0.4	0.5	0.3	2.3	3.3	23.2	26.5	71.2
30-39	-	0.2	0.5	0.4	0.5	0.3	1.9	5.5	22.5	28	70.2
39-65	-	0.5	0.6	0.4	0.3	0.1	1.9	1.6	15.1	16.7	81.3
65-90	-	0.8	0.6	0.3	0.2	0.2	2.1	0.8	17.3	18.1	80
90-120	-	0.2	0.2	0.2	0.1	0.1	0.8	5	20.3	25.3	74
120-150	-	0.1	0.1	0.1	0.2	0.1	0.6	10.3	27.7	38	61.5

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-14	-	-	-	52.1	68.4
14-30	-	-	-	50.9	71.2
30-39	-	-	-	41.7	70.2
39-65	-	-	-	2	81.3
65-90	-	-	-	3.5	80
90-120	-	-	-	1	74
120-150	-	-	-	24	61.5

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
0-14	5.9	5.1	2.91	-	2.00	-	-	-	-	5.0	3.1	1.7	0.2	10
14-30	5.6	4.7	0.56	-	1.98	-	-	-	-	5.0	2.7	0.9	0.4	9
30-39	6.0	5.0	0.43	-	1.20	-	-	-	-	5.8	2.8	0.4	0.4	9.4
39-65	6.4	5.4	0.29	-	0.45	-	-	-	-	4.6	3.0	0.2	0.2	8
65-90	6.6	5.8	0.21	-	0.3	-	-	-	-	5.0	3.8	0.2	0.2	9.2
90-120	6.7	5.9	0.19	-	0.37	-	-	-	-	4.6	4.3	0.2	0.4	9.5
120-150	6.8	6.0	0.21	-	0.42	-	-	-	-	3.7	4.4	0.1	0.4	8.6

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 %
0-14	65	15.4	23	7	-	-	-
14-30	61	14.7	21	6.9	-	-	-
30-39	80	11.8	17	4.2	-	-	-
39-65	92	8.7	11	1.6	-	-	-
65-90	103	8.9	11	1.1	-	-	-
90-120	101	9.4	13	1.3	-	-	-
120-150	96	9	15	1.5	-	-	-

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
0-14	-	-	-	0.26	0.07	6.97	0.41	-	-	-	0.26
14-30	-	-	-	0.26	0.06	7.09	0.43	-	-	-	0.27
30-39	-	-	-	0.22	0.07	7.03	0.37	-	-	-	0.27
39-65	-	-	-	0.15	0.09	7.15	0.31	-	-	-	0.36
65-90	-	-	-	0.14	0.1	8.03	0.36	-	-	-	0.42
90-120	-	-	-	0.14	0.1	8.65	0.39	-	-	-	0.44
120-150	-	-	-	0.15	0.1	8.3	0.53	-	-	-	0.39

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
65-90	34.8	30.1	17.1	0.04	0.14	0.94	-	2.52
120-150	34.1	29.8	19.1	0.04	0.09	0.5	-	2.66

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
65-90	0.17	0.1	11.7	-	2	5.4	1.4	2.8
120-150	0.07	0.72	12.1	-	1.9	4.7	1.4	2.4

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-14	-	-	-	-	-	-	medium to strong	weak	-	-	-	-
14-30	-	-	-	-	-	-	medium to strong	weak	-	-	-	-
30-39	-	-	-	-	-	-	medium to strong	weak	-	-	-	-
39-65	-	-	-	-	-	-	medium to strong	very weak to weak	-	-	-	-
65-90	-	-	-	-	-	-	medium to strong	very weak to weak	-	-	-	-
90-120	-	-	-	-	-	-	medium to strong	very weak	-	-	-	-

Sand mineralogy

Depth (cm)	Heavy Frac. sand % w/w	K-Feldspar % w/w	Light Fra. sand % w/w	Opaque % w/w	Plagioclase % w/w	Quartz % w/w
120-150	18.2	2	81.8	-	-	47

Profile description

Ap1 0-14 cm	dark reddish brown (2.5YR 3/4, dry) dark reddish brown (2.5YR 2.5/4, moist)silty clay,strong very fine subangular blocky to strong medium subangular blocky,extremely hard firm sticky plastic,many very fine pores,frequent small hard manganiferous concretions,gradual smooth boundary to,
Ap2 14-30 cm	dark reddish brown (2.5YR 3/4, dry) dark reddish brown (2.5YR 2.5/4, moist)silty clay,moderate very fine subangular blocky to moderate medium subangular blocky,very hard friable sticky plastic,many very fine pores,frequent small hard manganiferous concretions,clear smooth boundary to,
30-39 cm	dark reddish brown (2.5YR 3/4, dry) dark reddish brown (2.5YR 2.5/4, moist)silty clay,moderate fine and medium subangular blocky,very hard firm sticky plastic,many very fine pores,frequent small hard manganiferous concretions,abrupt smooth boundary to,
Bt1 39-65 cm	dark red (10R 3/6, dry) dusky red (10R 3/4, moist)silty clay,moderate fine and medium subangular blocky,hard friable slightly sticky plastic,patchy thin clay cutans,many very fine pores,frequent small hard manganiferous concretions,clear smooth boundary to,
Bt2 65-90 cm	dark red (10R 3/6, dry) dusky red (10R 3/4, moist)silty clay,strong very fine subangular blocky to strong medium subangular blocky,hard friable sticky plastic,broken thin clay cutans,many very fine pores,few small hard manganiferous concretions,gradual smooth boundary to,
Bt3 90-120 cm	dark red (10R 3/6, dry) dusky red (10R 3/4, moist)silty clay,strong very fine subangular blocky to strong medium subangular blocky,extremely hard friable sticky plastic,broken moderately thick clay cutans,many fine pores,diffuse smooth boundary to,
Bt4 120-150 cm	dark red (10R 3/6, dry) dusky red (10R 3/4, moist)silty clay,strong very fine and fine subangular blocky,extremely hard friable sticky plastic,broken moderately thick clay cutans,many fine pores,

Kind 1 (parent material) ; Parker (eds), 1984	fine-grained basic igneous rock
Mode of accumulation or deposition of parent material	residual material
Soil Depth	150cm
Texture of parent material (second entry)	clayey
General characterization of the status of weathering of solid rock	highly

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Slope stability	stable

Major crops	maize
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	arable farming
Remarks on Land Use / Vegetation	rotation maize - vegetables

Altitude	150m
Physiographic Unit	slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	pediplain
Slope	2%
Slope Aspect	south-south-east
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Dry From - To	0-150cm
Flooding frequency (FAO, 1986)	never
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
Microrelief pattern	none
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 United States of America 09: Ferralsol

Characteristics

Reference soil US009: Ferralsols

Classification