Reference soil Costa Rica 08: Ferralsol

CR008

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 CR008: Ferralsols

Brief soil description: very deep, well drained, brown clay soil, strongly acid and having a very low sum of exchangeable bases. Parent material is of fluvio-laharic origin. The original texture is not known. Composition parent material is probably andesitic. The pan has a black color and occurs at about 140cm depth. Actual classification: FAO (1988): Haplic Ferralsol USDA (1992): Andic Haploperox

Classification

WRB 2006

WRB 1998

Haplic- Ferralsol (Alumic Clayic Rhodic)

Rhodi-Alumic- Ferralsol

15-140 cm

ferralic horizon

0-15 cm	ochric horizon
15-140 cm	ferralic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Rhodi-Ferralic Cambisol

Rhodic Ferralsol

0-15 cm	ochric A horizon
15-140 cm	cambic B horizon
-	ferralic

0-15 cm	ochric A horizon
15-140 cm	oxic B horizon

Local classification:	Suelo Neguev

Other classification

USDA-SCS (1975)

Haplorthox perudic clayey 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
0-15	0	0.1	0.4	1.0	2.8	2.1	6.4	6.1	18.2	24.3	69.3
15-60	0	0.1	0.4	1.1	3.0	2.2	6.8	7.2	22.2	29.4	63.8
60-140	0	0.1	0.4	1.1	3.1	1.7	6.4	5.4	20.5	25.9	67.9

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-15	-	-	-	14.2	69.3
1-6	0.947	-	-	-	-
15-60	-	-	-	2.1	63.8
13-18	0.954	-	-	-	-
65-70	0.867	-	-	-	-
60-140	-	-	-	2.0	67.9

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	0.947	63.6	61.5	59.0	56.6	55.7	52.6	42.2	40.1
13-18	0.954	61.0	59.3	53.8	49.1	47.9	45.3	43.7	42.6
65-70	0.867	62.0	60.2	53.0	46.6	45.1	42.5	38.4	37.1

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
0-15	3.9	3.6	0.34	-	3.84	0.44	9	6.4	5.2	0.4	0.3	0.4	0.0	1.1
15-60	4.3	4.0	0.03	-	0.94	0.14	7	3.8	3.2	0.0	0.0	0.1	0.0	0.1
60-140	4.4	4.0	0.03	-	0.55	0.10	6	3.1	2.4	0.0	0.0	0.0	0.1	0.1

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 %
0-15	6	19.4	28	13.4	-	27	0
15-60	1	10.0	16	3.3	-	32	0
60-140	1	9.2	14	1.9	-	26	1

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
0-15	-	-	-	0.50	0.05	-	-	-	-	-	0.70
15-60	-	-	-	0.70	0.06	-	-	-	-	-	0.73
60-140	-	-	-	0.63	0.06	-	-	-	-	-	0.73

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	weak	weak	-	-	medium to strong	-	very weak	-	-	-
15-60	-	-	weak	weak	-	-	medium to strong	-	very weak	-	-	-
60-140	-	-	weak	weak	-	-	medium to strong	-	very weak	-	-	-

Profile description

Ah 0-15 cm	dark brown (10YR 3/3, moist)silty clay,moderate fine and medium crumb,very friable slightly sticky slightly plastic,many fine to coarse continuous exped and inped interstitial random pores and many continuous exped and inped tubular random pores highly porous (>60 v,clear wavy boundary to,
Bw1 15-60 cm	dark yellowish brown (10YR 3/4, moist)silty clay,weak porous massive,very friable slightly sticky slightly plastic,many fine to coarse continuous exped and inped tubular random pores highly porous (>60 vol%),clear smooth boundary to,
Bw2 60-140 cm	dark yellowish brown (10YR 3/4, moist)silty clay,weak porous massive,very friable slightly sticky slightly plastic,many fine to coarse continuous exped and inped tubular random pores,discontinuous massive weakly cemented iron pan pans,

Kind 1 (parent material) ; Parker (eds), 1984	fine-grained intermediate igneous rock
Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	fluvio-laharic origin
Soil Depth	150cm
Texture of parent material	clayey
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	highly

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	(semi-)natural vegetation
Remarks on Land Use / Vegetation	VEGETATION: Remaining forest island of about 6ha
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant
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	30m
Physiographic Unit	flat top Pleistocene terrace
Physiographic position of the site	flat
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	alluvial terrace
Slope	0%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

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	0-140cm
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	very 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
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	level
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 Costa Rica 08: Ferralsol

Characteristics

Reference soil CR008: Ferralsols

Classification