Reference soil Peru 04: Acrisol

PE004

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 PE004: Acrisols

Short field description Deep, moderately well drained dark grey sand. A 1 cm thick continuous iron pan (Placic horizon) with irregular boundary is present at a depth of about 125 cm. The soil has been truncated and the surface soil layer exposed is a dark coloured B horizon. The 1 cm thick Placic horizon forms a limit for water percolation, and excess rain water will be transported laterally. The soil just above this horizon is saturated for most of the time. The soil has been truncated by, presumably, natural erosion from a thick white sand layer. This was the eluvial horizon, from which humus and iron has been completely removed by the podzolisation proces. The soil PE03 is representative for such sands.

Classification

WRB 2006

WRB 1998

Haplic- Acrisol (Albic Alumic Humic)

Albi-Arenic- Acrisol (Humic Alumic)

14-125 cm	albic horizon
65-125 cm	argic horizon

0-14 cm	ochric horizon
14-125 cm	albic horizon
65-125 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Placi-Albic Arenosol

Albic Arenosol

0-14 cm	ochric A horizon
14-125 cm	albic E horizon
- cm	spodic B horizon

0-14 cm

ochric A horizon

Other classification

USDA-SCS (1975)

Placorthod perudic 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
0-14	-	0.1	0.7	24.7	39.8	18.8	84.1	5.6	5.4	11.0	5.1
14-39	-	0.0	0.6	22.8	39.1	20.5	83.0	5.4	6.5	11.9	5.0
36-65	-	0.0	0.7	21.2	41.4	17.5	80.8	6.7	5.2	11.9	7.4
65-125	-	0.0	0.6	21.0	37.4	19.1	78.1	6.5	3.0	9.5	12.5
126-150	-	0.0	1.5	29.6	44.6	11.4	87.1	2.5	2.3	4.8	8.0

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
14-36	1.320	-	-	-	-
0-14	-	-	-	2.8	5.1
14-39	-	-	-	4.1	5.0
36-65	1.420	-	-	2.9	7.4
65-125	1.490	-	-	5.3	12.5
125-150	1.490	-	-	-	-
126-150	-	-	-	-	8.0

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
14-36	1.320	42.8	42.0	38.1	30.9	27.1	24.1	13.2	10.3
36-65	1.420	43.0	42.5	40.4	36.7	34.3	31.5	13.5	10.8
65-125	1.490	39.8	39.1	35.8	28.9	23.7	19.9	12.5	11.0
125-150	1.490	40.3	38.9	28.2	14.0	11.8	10.4	7.7	6.2

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
0-14	4.0	3.5	0.06	-	6.05	0.16	38	9.8	7.4	0.4	0.0	0.0	0.2	0.6
14-39	5.2	4.7	0.02	-	1.20	0.04	30	1.3	0.7	0.2	0.0	0.0	0.0	0.2
36-65	5.2	4.8	0.01	-	0.73	0.03	24	0.9	0.5	0.2	0.0	0.0	0.3	0.5
65-125	5.2	4.9	0.01	-	0.23	0.02	-	0.6	0.2	0.0	0.0	0.0	0.2	0.2
126-150	4.9	4.5	0.01	-	0.06	-	-	0.8	0.2	0.2	0.0	0.0	0.3	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 %
0-14	2	29.1	571	11.2	-	25	1
14-39	5	3.8	76	2.8	-	18	0
36-65	18	2.8	38	2.1	-	18	11
65-125	14	1.4	11	0.8	-	14	14
126-150	71	0.7	9	0.2	-	29	43

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
0-14	-	-	-	-	-	-	-	0.60	0.00	-	-
14-39	-	-	-	-	-	-	-	0.50	0.00	-	-
36-65	-	-	-	-	-	-	-	0.40	0.10	-	-
65-125	-	-	-	-	-	-	-	0.30	0.10	-	-
126-150	-	-	-	-	-	-	-	0.10	0.20	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-14	-	-	weak	weak	-	-	strong	very weak to weak	weak	-	weak	-
14-39	-	weak	medium to strong	weak	-	-	weak to medium	-	weak	-	weak	-
36-65	-	weak	medium to strong	weak	-	-	medium to strong	-	weak	-	weak	-
65-125	-	weak	medium to strong	weak	-	-	strong	-	weak	-	weak	-
126-150	-	weak	weak	weak	-	-	very strong	-	weak	-	weak	-

Rare clay minerals

Depth (cm)	Amphibole	Augite	Calcite	Lepidococrite	Pyrophillite	Pyroxene	Weddelite
0-14	-	-	-	-	medium to strong	-	-

Profile description

Ah 0-14 cm	dark brown (7.5YR 3/2, moist) dark reddish brown (5YR 2.5/2, dry)very pale brown (10YR 7/4, moist) strong brown (7.5YR 5/6, dry),fine sand,fine sand,moderately coherent porous massive,strongly coherent porous massive,parting to non sticky non plastic,very friable non sticky non plastic,few very fine pores,abrupt wavy boundary to,
E2 36-65 cm	very pale brown (10YR 7/4, moist) yellowish brown (10YR 5/6, dry)fine sand,weakly coherent porous massive,friable non sticky slightly plastic,few very fine pores,diffuse wavy boundary to,
E3 65-125 cm	white (10YR 8/2, moist) brownish yellow (10YR 6/6, dry)loamy fine sand,structureless single grain,very friable non sticky slightly plastic,common fine distinct mottles,few very fine pores,abrupt wavy boundary to,
Bsm 125-126 cm	yellowish brown (10YR 5/6, moist) dark yellowish brown (10YR 4/6, dry)reddish yellow (7.5YR 6/8, moist) strong brown (7.5YR 5/8, dry),fine sand,structureless single grain,extremely firm,very friable non sticky non plastic,continuous platy indurated iron pan pans,abrupt wavy boundary to,
C 150-180 cm	fine sandstructureless single grain,loose non sticky non plastic,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	Tertiary Iquitos formation
Soil Depth	125cm
Texture of parent material	sandy
Weathering Resistance	high
General characterization of the status of weathering of solid rock	highly

Land use or vegetation in the immediate vicinity of the site	(semi-)natural vegetation
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	secondary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	closed forest

Altitude	130m
Physiographic Unit	flat area of old river terrace
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	2%
Form of the slope surrounding the site	undulating
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Lower limit of a slow permeable or stagnating layer in the profile	126cm
Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-180cm
Estimated permeability (class) of least permeable part of the profile	slow
Upper limit of a slow permeable or stagnating layer in the profile	125cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
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 04: Acrisol

Characteristics

Reference soil PE004: Acrisols

Classification