Reference soil Peru 11: Ferralsol

PE011

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 PE011: Ferralsols

Short field description A very deep, well drained, yellowish brown clay overlying a yellowish red clay. At a depth of about 20 cm are some rounded, partly broken gravel stones. The subsoil is strongly mottled and has iron concretions. The Bt1 horizon can be divided in two layers: from 64-78 cm with the maximum concentration of iron/manganese concretions and 78-100 cm with very few concentrations. The soil colour from 78 to 150 cm is heterogenous and consists of a mix of yellowish, brownish and reddish colours. This may be indicative for water saturation during some part of the year. The soil is located in 'Tierra firme', terrain not flooded by rivers, located in a high terrace. The rounded stones in the topsoil are indicating that the soil may also be derived from an old alluvium. The land has been cultivated for about 65 years, recently it is pasture land, which is burned each year in september. In the FAO 1988 classification the soil classifies as Haplic Lixisol. Because no cutans were observed in the field, no argillic horizon can be recognized in FAO (1974), therefore the soil classifies as Ferralic Cambisol.

Classification

WRB 2006

WRB 1998

Lixic- Ferralsol (Eutric Clayic)

Lixic- Ferralsol

37-130 cm	ferralic horizon
37-150 cm	argic horizon
-	abrupt textural change

0-37 cm	ochric horizon
37-130 cm	ferralic horizon
37-150 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Abrupti-Haplic Lixisol

Orthic Ferralsol

0-37 cm	ochric A horizon
37-150 cm	argic B horizon
- cm	ochric A horizon
-	abrupt textural change

0-37 cm	ochric A horizon
-	abrupt textural change

Other classification

USDA-NRCS (1999)

Typic Kandiudalf

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	-	0.1	0.6	10.6	26.5	14.7	52.5	14.7	20.5	35.2	12.4
6-17	-	0.2	0.7	11.3	14.2	19.3	45.7	19.0	22.8	41.8	12.5
17-37	-	0.2	0.5	8.6	25.8	16.2	51.3	15.7	20.7	36.4	12.5
37-64	-	0.1	0.3	4.7	15.9	11.3	32.3	12.9	19.7	32.6	35.2
64-100	-	0.2	0.3	3.1	12.7	9.0	25.3	12.7	16.7	29.4	45.3
100-130	-	0.1	0.2	2.3	11.5	11.5	25.6	13.0	17.6	30.6	43.8
130-150	-	0.0	0.1	1.4	9.4	13.2	24.1	14.5	19.3	33.8	42.2

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	1.160	-	-	6.2	12.4
6-17	1.470	-	-	6.2	12.5
17-37	-	-	-	6.2	12.5
17-34	1.530	-	-	-	-
37-64	-	-	-	7.1	35.2
34-68	1.610	-	-	-	-
64-100	-	-	-	14.9	45.3
68-100	1.560	-	-	-	-
100-130	1.550	-	-	5.7	43.8
130-150	-	-	-	3.8	42.2

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
0-6	1.160	47.1	47.1	45.9	38.4	33.2	30.7	12.7	12.0
6-17	1.470	37.6	37.5	34.8	29.1	24.8	23.0	10.9	10.0
17-34	1.530	33.9	33.7	29.6	24.4	20.8	18.8	11.6	10.9
34-68	1.610	35.2	35.2	32.9	28.5	26.0	24.8	24.9	23.9
68-100	1.560	40.1	40.1	38.1	35.8	34.2	33.5	24.1	23.0
100-130	1.550	41.4	41.4	40.3	38.3	36.5	35.6	29.1	28.1

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
0-6	5.9	5.2	0.04	-	2.44	0.17	14	-	-	2.4	0.3	0.1	0.0	2.8
6-17	6.1	5.3	0.04	-	0.63	0.07	9	-	-	2.0	0.3	0.0	0.1	2.4
17-37	6.0	5.1	0.03	-	0.28	0.04	7	-	-	1.4	0.3	0.0	0.1	1.8
37-64	5.1	4.0	0.02	-	0.25	0.06	4	1.7	1.1	1.4	1.0	0.3	0.0	2.7
64-100	5.1	3.9	0.02	-	0.27	0.06	5	2.7	1.8	1.2	1.4	0.3	0.0	2.9
100-130	5.0	3.9	0.01	-	0.15	-	-	3.2	2.3	1.6	1.4	0.2	0.2	3.4
130-150	5.0	3.9	0.01	-	0.12	-	-	4.6	3.7	1.2	1.4	0.1	0.1	2.8

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	33	8.5	69	8.5	-	-	0
6-17	60	4.0	32	2.2	-	-	3
17-37	51	3.5	28	1.0	-	-	3
37-64	51	5.3	15	0.9	-	21	0
64-100	51	5.7	13	0.9	-	32	0
100-130	44	7.7	18	0.5	-	30	3
130-150	23	12.4	29	0.4	-	30	1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-6	-	-	-	weak	-	-	weak to medium	weak to medium	-	weak	weak	-
6-17	-	-	-	weak	-	-	weak to medium	weak to medium	-	weak	weak	-
17-37	-	-	-	weak	-	-	weak to medium	weak to medium	-	weak	weak	-
37-64	-	-	-	weak	-	-	medium to strong	weak to medium	-	-	weak	-
64-100	-	-	-	weak	-	-	strong	weak	-	-	weak	-
100-130	-	-	-	medium to strong	-	-	strong	weak to medium	-	-	weak	-
130-150	-	-	-	medium to strong	-	-	strong	weak to medium	-	-	weak	-

Profile description

Ap1 0-6 cm	(10YR 2.5/1, moist)sandy loam,weak medium granular to moderate fine granular,friable,frequent mycelium and pedotubules,abrupt smooth boundary to,
Ap2 6-17 cm	yellowish brown (10YR 5/6, moist)loam,weak medium subangular blocky to moderate medium subangular blocky,friable,few mycelium and pedotubules,diffuse smooth boundary to,
17-37 cm	strong brown (7.5YR 5/6, moist)loam,weak medium subangular blocky to moderate medium subangular blocky,friable,clear smooth boundary to,
Bt1 37-64 cm	(5YR 4/8, moist)clay loam,weak medium subangular blocky to moderate medium subangular blocky,firm,common fine prominent clear mottles (10YR 5/6),very few medium irregular hard ferruginous concretions,gradual smooth boundary to,
Bt2 64-100 cm	yellowish red (5YR 5/8, moist)clay,moderate medium subangular blocky,fine and medium,common fine distinct diffuse mottles (10YR 5/6),few medium irregular hard ferruginous concretions,gradual smooth boundary to,
Bt3 100-130 cm	yellowish red (5YR 5/8, moist)clay,moderate medium and coarse subangular blocky,very friable,common fine distinct diffuse mottles (10YR 5/6),diffuse smooth boundary to,
Bt4 130-150 cm	yellowish red (5YR 5/8, moist)clay,moderate medium and coarse subangular blocky,very friable,common fine distinct diffuse mottles (10YR 5/6),

Kind 1 (parent material) ; Parker (eds), 1984	non-calcareous claystone
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	'Arcillolitas'
Soil Depth	150cm
Texture of parent material	clayey
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

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

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	cultivated pasture
Remarks on Land Use / Vegetation	VEGETATION: "Pasture ""yaragua"" (Hyparrhenia rufa)" LANDUSE:
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)	modified
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	short grassland

Altitude	250m
Physiographic Unit	slightly dissected high terrace
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	alluvial plain
Slope	2%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	moderately 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)	slow
Drainage class - intergrade; FAO (2006) - Guidelines for soil description	well

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
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 Peru 11: Ferralsol

Characteristics

Reference soil PE011: Ferralsols

Classification