Reference soil Peru 14: Acrisol

PE014

Acrisols occur dominantly in the wetter parts of the tropics and subtropics and the warm temperate regions in relatively young landscapes.

Characteristics

Soils having an argic horizon (a subsurface horizon with distinct higher clay content than the overlying horizon), which has a cation exchange capacity of less than 24 cmolc per kg in some part, either starting within 100 cm from the soil surface, or within 200 cm from the soil surface if the argic horizon is overlain by loamy sand or coarser textures throughout. They have a base saturation (total amount of Ca, Mg, K and Na with respect to the cation exchange capacity) of less than 50 percent in the major part between 25 and 100 cm from the soil surface

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil PE014: Acrisols

Classification

WRB 2006

WRB 1998

Cutanic-Vetic- Acrisol (Alumic Profondic Arenic)

Veti-Arenic- Acrisol (Profondic Alumic)

52-182 cm

argic horizon

0-32 cm	ochric horizon
52-182 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Alumi-Haplic Acrisol

Orthic Acrisol

52-182 cm	argic B horizon
7-32 cm	ochric A horizon

7-32 cm

ochric A horizon

Local classification:	Altura

Other classification

USDA-NRCS (1999)	Arenic Paleudult
USDA-SCS (1975)	Arenic Paleudult udic coarse-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
7-15	0	0.3	3.4	33.5	47.8	7.2	92.2	4.3	1.8	6.1	1.8
15-32	0	0.3	2.9	31.6	44.0	5.6	84.4	6.6	3.3	9.9	5.8
32-52	0	0.1	2.4	25.4	44.5	9.7	82.1	6.5	5.0	11.5	6.5
52-82	0	0.1	2.3	27.5	43.0	6.9	79.8	6.1	4.6	10.7	9.5
82-132	0	0.2	2.5	27.5	43.2	8.8	82.2	5.5	4.3	9.8	8.0
132-182	0	0.1	2.4	27.9	43.6	6.7	80.7	5.4	4.2	9.6	9.8
290-310	0	0.1	2.0	27.7	43.5	9.4	82.7	5.1	2.9	8.0	9.2
390-410	0	0.2	1.8	26.0	53.8	5.6	87.4	3.7	2.5	6.2	6.4
490-510	0	0.2	1.8	27.8	57.5	4.6	91.9	2.8	1.8	4.6	3.8
740-760	0	0.8	7.0	50.5	35.2	1.1	94.6	2.0	1.2	3.2	2.2

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-8	1.220	-	-	-	-
8-25	1.300	-	-	-	-
7-15	-	-	-	-	1.8
25-45	1.340	-	-	-	-
15-32	-	-	-	-	5.8
32-52	-	-	-	-	6.5
45-75	1.360	-	-	-	-
75-125	1.410	-	-	-	-
52-82	-	-	-	-	9.5
82-132	-	-	-	-	8.0
125-170	1.450	-	-	-	-
132-182	-	-	-	-	9.8
290-310	-	-	-	-	9.2
390-410	-	-	-	-	6.4
490-510	-	-	-	-	3.8
740-760	-	-	-	-	2.2

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
0-8	1.220	39.3	33.3	23.8	9.7	7.4	6.5	3.5	3.5
8-25	1.300	43.4	40.5	32.2	21.0	17.7	15.7	11.0	5.7
25-45	1.340	44.3	41.4	35.1	28.5	25.6	23.0	14.4	8.1
45-75	1.360	39.8	34.9	32.1	24.4	22.3	20.6	13.2	9.1
75-125	1.410	40.7	34.5	29.2	20.6	18.3	16.5	13.4	9.6
125-170	1.450	35.7	32.9	28.3	20.3	18.2	16.9	13.5	10.1

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
7-15	4.4	3.6	0.12	-	0.41	0.04	10	0.6	0.4	0.0	0.0	0.0	0.2	0.2
15-32	3.8	3.8	0.17	-	0.67	0.05	13	1.7	1.3	0.2	0.0	0.0	0.2	0.4
32-52	4.3	4.3	0.05	-	0.48	0.04	12	1.2	1.1	0.0	0.1	0.0	0.0	0.1
52-82	4.5	4.4	0.03	-	0.35	-	-	0.8	0.7	0.0	0.0	0.0	0.4	0.4
82-132	4.9	4.7	0.02	-	0.24	-	-	0.7	0.4	0.0	0.0	0.0	0.0	0.0
132-182	5.0	4.5	0.03	-	0.14	-	-	0.4	0.4	0.0	0.0	0.0	0.0	0.0
290-310	4.7	4.2	0.02	-	0.05	-	-	0.6	0.4	0.0	0.0	0.0	0.1	0.1
390-410	4.8	4.1	0.02	-	0.03	-	-	0.8	0.7	0.0	0.1	0.0	0.1	0.2
490-510	4.8	4.2	0.02	-	0.01	-	-	0.7	0.7	0.0	0.0	0.0	0.4	0.4
740-760	5.0	4.3	0.01	-	0.01	-	-	0.3	0.2	0.0	0.0	0.0	0.4	0.4

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 %
7-15	20	1.0	56	1.4	-	40	20
15-32	17	2.4	41	2.3	-	54	8
32-52	5	2.2	34	1.7	-	50	0
52-82	25	1.6	17	1.2	-	44	25
82-132	0	0.7	9	0.8	-	57	0
132-182	0	0.7	7	0.5	-	57	0
290-310	11	0.9	10	0.2	-	44	11
390-410	22	0.9	14	0.1	-	78	11
490-510	57	0.7	18	0.0	-	100	57
740-760	57	0.7	32	0.0	-	29	57

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
7-15	-	1.7	-	-	-	-	-	-	-
15-32	-	1.4	-	-	-	-	-	-	-
32-52	-	0.8	-	-	-	-	-	-	-
52-82	-	0.9	-	-	-	-	-	-	-
82-132	-	1.5	-	-	-	-	-	-	-
132-182	-	0.9	-	-	-	-	-	-	-
290-310	-	0.7	-	-	-	-	-	-	-
390-410	-	1.2	-	-	-	-	-	-	-
490-510	-	1.6	-	-	-	-	-	-	-
740-760	-	1.3	-	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
7-15	-	very weak	weak	-	-	-	weak to medium	-	weak	very weak	-	-
32-52	-	weak	weak	-	-	-	strong	-	weak	very weak	weak	-
82-132	-	weak	weak	-	-	-	strong	-	weak	very weak	weak	-
290-310	-	weak	weak	-	-	-	strong to very strong	-	weak	-	weak	-

Rare clay minerals

Depth (cm)	Amphibole	Augite	Calcite	Lepidococrite	Pyrophillite	Pyroxene	Weddelite
7-15	-	-	-	-	very weak	-	-
32-52	-	-	-	-	weak	-	-
82-132	-	-	-	-	weak	-	-
290-310	-	-	-	-	very weak	-	-

Profile description

Oe 0-7 cm	moderately decomposed organic leaves loose,abrupt smooth boundary to,
Ah 7-15 cm	yellowish brown (10YR 5/8, moist)Description: sand,very friable,common very fine and fine throughout roots,clear wavy boundary to,
15-32 cm	yellowish brown (10YR 5/6, moist)loamy sand,weak medium granular,friable,common medium prominent sharp mottles (7.5YR 4/4),patchy thin manganese (hydr-)oxide throughout cutans,few very fine and fine throughout roots,clear wavy boundary to,
BA 32-52 cm	(10YR 5/5, moist)sandy loam,weak medium granular,friable,common fine distinct clear mottles (7.5YR 4/4),patchy thin manganese (hydr-)oxide throughout cutans,few fine throughout roots,gradual smooth boundary to,
Bh 52-82 cm	yellowish brown (10YR 5/8, moist)sandy loam,weak medium subangular blocky,friable,few fine throughout roots,gradual smooth boundary to,
Bw1 82-132 cm	yellowish brown (10YR 5/8, moist)sandy loam,weak medium subangular blocky,very friable,few fine throughout roots,diffuse smooth boundary to,
Bw2 132-177 cm	strong brown (7.5YR 5/8, moist)sandy loam,weak medium subangular blocky,very friable,no roots,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	Arena Pardo Amarillen
Soil Depth	150cm
Texture of parent material	sandy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

Intensity of the soil erosion type	slight
Soil erosion type	sheet

Land use or vegetation in the immediate vicinity of the site	natural forest and woodland
Remarks on Land Use / Vegetation	VEGETATION: Tree species: Pashaco, Mohena amarilla, Copal. Shrubs: Sacha-huiro. Herbs: sacha-bijao LANDUSE:
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	evergreen forest

Altitude	130m
Physiographic Unit	colinas bajas
Physiographic position of the site	crest
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	hill
Slope	0%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	hilly

Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
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
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 14: Acrisol

Characteristics

Reference soil PE014: Acrisols

Classification