Reference soil Peru 06: Acrisol

PE006

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil PE006: Acrisol

Short field description A very deep, well drained, brown clay. The topsoil has a loamy texture. The soil site is located in an old alluvium plain, not any more flooded ('Tierra Firme'), with a nearly level to gently undulating relief. In the surrounding area at a distance of about 5 km starts a dissected higher hilly area. The site is comparable to soil profile Yurimaguas 17 in the thesis " Genesis of the soils within a detailed soil survey area in the upper Amazon basin, Yurimaguas, Peru" by E.J. Tyler (North Carolineat Raleigh, 1975). Many experiments of the Tropsoils programme (P.Sanchez) are realized on this soil type. Slight sheet erosion is manifest. The textural increase is sufficient for the recognition of an argic B horizon in FAO (1988) classification system and classifies as Haplic Acrisol. However, because no cutans were observed in the field no argillic horizon can be recognized in FAO (1974) and therefore the soil is classified as Ferralic Cambisol. A similar remark can be made for the USDA classification: if no clay skins are detected in thin sections, the soil is classified as Oxic Dystropept.

Classification

WRB 2006

WRB 1998

Haplic- Acrisol (Alumic Chromic)

Chromi-Alumic- Acrisol

8-114 cm

argic horizon

0-8 cm	ochric horizon
8-114 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

AlumiHaplic Acrisol

Orthic Acrisol

0-8 cm	ochric A horizon
8-114 cm	argic B horizon
- cm	ochric A horizon

0-8 cm	ochric A horizon
8-114 cm	argillic B horizon

Local classification:	Suelo Yurimaguas

Other classification

USDA-NRCS (1999)	Typic Paleudult
USDA-SCS (1975)	Typic Paleudult udic fine-loamy siliceous 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
0-8	-	0.2	1.5	5.7	26.8	25.1	59.3	16.2	13.2	29.4	11.4
8-25	-	0.2	0.7	3.0	19.2	21.9	45.0	19.6	16.8	36.4	18.6
25-47	-	0.2	0.9	2.6	17.6	22.5	43.8	18.0	16.8	34.8	21.4
47-76	-	0.1	0.9	2.3	16.3	20.5	40.1	18.2	16.5	34.7	25.3
76-114	-	0.2	0.8	2.0	16.9	19.1	39.0	16.1	14.0	30.1	31.0
114-150	-	0.2	0.9	1.9	19.4	19.9	42.3	16.3	12.4	28.7	28.9

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-8	-	-	-	2.5	11.4
8-25	-	-	-	4.7	18.6
25-47	-	-	-	6.4	21.4
47-76	-	-	-	7.9	25.3
76-114	-	-	-	10.6	31.0
114-150	-	-	-	7.6	28.9

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
0-8	4.1	3.6	0.17	-	2.58	0.20	13	3.2	2.2	1.0	0.3	0.2	0.1	1.6
8-25	4.6	4.0	0.03	-	0.59	0.00	-	4.4	3.6	0.2	0.0	0.1	0.0	0.3
25-47	4.7	4.0	0.02	-	0.31	0.05	6	4.8	3.8	0.2	0.0	0.0	0.0	0.2
47-76	4.7	4.0	0.02	-	0.24	0.04	8	5.4	4.5	0.2	0.0	0.1	0.1	0.4
76-114	4.7	4.0	0.02	-	0.16	-	-	6.3	5.2	0.2	0.0	0.0	0.1	0.3
114-150	4.7	4.0	0.02	-	0.14	-	-	5.7	4.8	0.2	0.0	0.1	0.2	0.5

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 %
0-8	20	8.1	71	9.0	-	27	1
8-25	5	6.6	35	2.1	-	55	2
25-47	3	6.4	30	1.1	-	59	0
47-76	7	6.0	24	0.8	-	75	0
76-114	4	7.3	24	0.6	-	71	6
114-150	7	6.8	24	0.5	-	71	7

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
0-8	-	-	-	0.10	0.00	0.60	0.00	-	-	-	0.20
8-25	-	-	-	0.10	0.00	0.90	0.10	-	-	-	0.20
25-47	-	-	-	0.10	0.00	0.90	0.10	-	-	-	0.10
47-76	-	-	-	0.10	0.00	1.10	0.20	-	-	-	0.10
76-114	-	-	-	0.10	0.00	1.30	0.20	-	-	-	0.00
114-150	-	-	-	0.10	0.00	1.10	0.10	-	-	-	0.00

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-8	-	-	-	weak	-	-	very strong	-	strong	weak	-	-
8-25	-	-	-	weak	-	-	very strong	-	strong	weak	-	-
25-47	-	-	-	weak	-	-	very strong	-	strong	weak	-	-
47-76	-	-	-	weak	-	-	very strong	-	strong	weak	-	-
76-114	-	-	-	weak	-	-	very strong	-	strong	very weak	-	-
114-150	-	-	-	weak	-	-	very strong	-	strong	very weak	-	-

Profile description

Ah 0-8 cm	dark brown (10YR 3/3, moist)loam,weak very fine and fine granular,very friable,few krotovinas and worm channels,abrupt wavy boundary to,
BA 8-25 cm	yellowish brown (10YR 5/6, moist)silt loam,weak medium and coarse subangular blocky,friable,few krotovinas and worm channels,gradual wavy boundary to,
Bt1 25-47 cm	strong brown (7.5YR 5/6, moist)clay loam,weak medium subangular blocky,friable,few krotovinas and worm channels,gradual wavy boundary to,
Bt2 47-76 cm	yellowish red (5YR 5/8, moist)clay,weak medium subangular blocky,firm,gradual smooth boundary to,
Bt3 76-114 cm	yellowish red (5YR 5/8, moist)clay,weak medium subangular blocky,firm,gradual smooth boundary to,
114-150 cm	red (2.5YR 5/8, moist)clay,weakly coherent massive,very friable,

Kind 1 (parent material) ; Parker (eds), 1984	claystone
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	'Arcillitas'
Soil Depth	160cm
Texture of parent material	clayey
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	high

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	(semi-)natural vegetation
Remarks on Land Use / Vegetation	VEGETATION: Arborea (cetico, pashaco, mohena) 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)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	evergreen forest

Altitude	180m
Physiographic Unit	Llanura aluvial antigua
Physiographic position of the site	slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plain
Slope	4%
Form of the slope surrounding the site	undulating
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	steeply dissected

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	0-160cm
Estimated permeability (class) of least permeable part of the profile	slow
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
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 06: Acrisol

Reference soil PE006: Acrisol

Classification