Reference soil Democratic Republic of the Congo 01: Ferralsol

CD001

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 CD001: Ferralsols

WEATHER: Dry season, no rain for two weeks. MINERALOGY: Kaolinite, goethite, quartz. SURFACE DRAINAGE: Dendritic, medium dense. ADDITIONAL NOTES ON PROFILE DESCRIPTION: Ah - mottles: washed out sandgrains along peds. - roots: also common coarse roots. BA - mottles: also common 7.5YR3/4, and also very few red (2.5YR5/8). - roots: also few medium and coarse roots. Bws1 - mottles: also common 7.5YR3/4, and also very few red (2.5YR5/8). - roots: also very few medium and coarse roots. Bws2 - cutans: bridges.

Classification

WRB 2006

WRB 1998

Haplic- Ferralsol (Hyperdystric Xanthic)

Xanthi-Hyperdystric- Ferralsol

17-152 cm

ferralic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Hyperdystri-Xanthic Ferralsol

Xanthic Ferralsol

17-152 cm	ferralic B horizon
2-17 cm	ochric A horizon

17-152 cm	oxic B horizon
2-17 cm	ochric A horizon

Local classification:	Sol ferrallitique fortement désaturé jaune

Other classification

USDA-SCS (1975)

Haplorthox udic 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
2-17	-	0.9	14.7	36.0	23.1	3.7	78.4	1.6	0.8	2.4	19.2
17-34	-	0.9	14.3	33.7	23.7	3.9	76.5	1.6	0.5	2.1	21.5
40-70	-	0.6	13.9	32.1	22.6	3.7	72.9	0.8	1.3	2.1	25.0
82-110	-	0.8	15.0	30.2	19.7	3.4	69.1	2.0	0.7	2.7	28.1
120-152	-	1.0	14.2	29.0	22.2	3.8	70.2	1.3	0.8	2.1	27.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
2-17	-	-	-	6.6	19.2
15-20	1.271	-	-	-	-
17-34	-	-	-	12.1	21.5
40-60	1.333	-	-	-	-
40-70	-	-	-	17.3	25.0
130-150	1.388	-	-	-	-
82-110	-	-	-	1.0	28.1
120-152	-	-	-	0.5	27.8

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
15-20	1.271	38.3	30.6	24.4	19.2	18.3	16.9	11.6	10.9
40-60	1.333	42.1	39.3	25.3	20.8	19.4	18.2	13.3	12.8
130-150	1.388	40.2	35.8	28.3	23.9	22.7	21.4	15.0	14.3

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
2-17	3.9	3.5	0.17	-	1.54	0.11	14	1.8	1.5	0	0	0.1	0.2	0.3
17-34	4.2	3.9	0.06	-	0.4	0	-	1.2	1.1	0	0	0	0.4	0.4
40-70	4.4	4.0	0.04	-	0.27	0.02	14	1.2	1.0	0	0	0	0	-
82-110	4.3	4.0	0.07	-	0.22	-	-	1.2	1.1	0	0	0.1	0.1	0.2
120-152	4.3	4.0	0.05	-	0.22	-	-	1.1	1.1	0	0	0	0	-

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 %
2-17	5	5.7	-	5.4	-	26	4
17-34	11	3.5	-	1.4	-	31	11
40-70	-	3.7	-	0.9	-	27	0
82-110	6	3.5	-	0.8	-	31	3
120-152	-	3.3	9	0.8	-	33	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
2-17	-	-	-	0	0	1.3	0.2	-	-	-	0.1
17-34	-	-	-	0	0	1.6	0.2	-	-	-	0.1
40-70	-	-	-	0.1	0	1.7	0.2	-	-	-	0.1
82-110	-	-	-	0.1	0	1.8	0.3	-	-	-	0.1
120-152	-	-	-	0	0	1.7	0.3	-	-	-	0

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
2-17	-	-	1.75	-	-	-	-	-	-
17-34	-	-	8.6	-	-	-	-	-	-
40-70	-	-	1.0	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
2-17	-	very weak	-	weak	-	-	very strong	-	very weak	-	-	-
40-70	-	very weak	-	weak	-	-	very strong	-	very weak	-	-	-
120-152	-	very weak	-	weak	-	-	very strong	-	very weak	-	-	-

Profile description

O1 0-1 cm	organic, leaves nilnon calcareous,abrupt smooth boundary to,
O2 1-2 cm	organic leaves moderatelynon calcareous,abrupt smooth boundary to,
Ah 2-13 cm	dark brown (7.5YR 3/2, moist)loamy sand,moderate fine crumb and moderate very fine and fine subangular blocky structure,very friable slightly sticky slightly plastic,few (2-5%) faint mottles,no cutans,many very fine to coarse tubular pores and common coarse interstitial pores,no inclusions,no fragments,non calcareous,clear wavy boundary to,
BA 13-34 cm	(dark) brown (7.5YR 4/4, moist)sandy loam,weak fine crumb and weak to moderate very fine and fine subangular blocky structure,very friable sticky plastic,common (5-15%) medium faint dark brown mottles (7.5YR 3/2 ) and very few (0-2%) medium faint red mottles (2.5YR 5/8),no cutans,many micro to medium tubular and many medium interstitial pores,few medium and coarse roots,charcoal inclusions,charcoal fragments,non calcareous,gradual smooth boundary to,
Bo1 34-82 cm	(7.5YR 4/5, moist)sandy loam,weak coarse subangular blocky parting to weak very fine and fine subangular blocky,very friable sticky plastic,common (5-15%) medium faint mottles (7.5YR 3/2) and few (0-2%) medium faint diffuse mottles (2.5YR 5/8),no cutans,many micro to medium tubular pores and many medium interstitial pores,few medium and coarse roots,charcoal inclusions,charcoal fragments,non calcareous,diffuse smooth boundary to,
Bo2 82-152 cm	(7.5YR 4.5/6, moist)sandy clay loam,weak to moderate coarse subangular blocky parting to weak to moderate very fine and fine subangular blocky structure,very friable sticky plastic,few (2-5%) medium faint diffuse mottles (2.5YR 5/8) mottles,patchy clay cutans between sand grains,many micro medium tubular pores and many medium interstitial pores,no inclusions,no fragments,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	eolian mixed / undifferentiated
Remarks on Parent Materials	Pleistocene
Texture of parent material	loamy

Remarks on Land Use / Vegetation	Coverage trees: 100%
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	evergreen forest

Altitude	440m
Physiographic Unit	Uplands
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.	plateau
Slope	3%
Slope Aspect	south
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	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	high
Estimated run off (class)	slow

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 Height: variation in height	50
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	termite/ant mounds
Microrelief pattern	isolated
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 Democratic Republic of the Congo 01: Ferralsol

Characteristics

Reference soil CD001: Ferralsols

Classification