Reference soil Peru 23: Phaeozem

PE023

Phaeozems occur all over the world, but especially on the more moist side of the steppe regions, bordering Chernozems.

Characteristics

Soils having a mollic horizon (deep, brownish or blackish surface horizon with a significant accumulation of organic matter and high base saturation); a base saturation of 50 percent or more between 25 and 100 cm from the soil surface; a calcium carbonate-free soil matrix at least to a depth of 100 cm from the soil surface, or to a contrasting layer between 25 and 100 cm; no diagnostic horizons other than an albic, argic, cambic or vertic horizon, or a petrocalcic horizon in the substratum.

Distribution of Phaeozems (rough estimation supplied by soilgrids)

Reference soil PE023: Phaeozems

Short field description Soil profile located on the left bank of the Urubamba river, in a fan (derived from colluvium-alluvium material). It is a deep, well drained, dark reddish brown clay loam.. This land has been cultivated for about 100 years, the last nine years with Alfalfa in rotation with crops such as potatoes, corn and lima beans. The technology level is high (use of fertilizers, mechanization and pesticides).

Classification

WRB 2006

WRB 1998

Haplic- Phaeozem (Calcaric Chromic)

Calcari-Mollihumic- Regosol

0-43 cm	mollic horizon
43-68 cm	cambic horizon
-	calcaric
-	fluvic

0-43 cm	mollic horizon
43-68 cm	cambic horizon
-	calcaric
-	fluvic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Calcaric Phaeozem

Calcaric Phaeozem

0-43 cm	mollic A horizon
42-68 cm	cambic B horizon
- cm	mollic A horizon
-	calcaric

0-42 cm

mollic A horizon

Local classification:	Suelo Tinta

Other classification

USDA-NRCS (1999)	Fluventic Haplustoll
USDA-SCS (1975)	Fluventic Haplustoll ustic fine mixed (calcareous) isomesic

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
0-17	-	1.9	4.4	7.3	12.1	12.2	37.9	19.9	12.8	32.7	29.4
17-42	-	1.2	3.8	6.3	10.6	12.0	33.9	20.5	14.4	34.9	31.2
42-68	-	1.9	3.2	4.5	7.1	9.9	26.6	22.2	16.1	38.3	35.0
68-104	-	1.4	2.8	4.7	8.0	10.3	27.2	21.8	15.8	37.6	35.3
104-150	-	2.8	7.5	7.6	5.9	7.0	30.8	18.0	15.6	33.6	35.5

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-17	1.510	-	-	13.6	29.4
17-42	1.590	-	-	14.6	31.2
42-68	1.630	-	-	14.8	35.0
68-104	1.750	-	-	18.1	35.3
104-150	1.690	-	-	22.7	35.5

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
0-17	1.510	39.0	35.6	33.1	29.7	27.7	26.5	21.6	19.3
17-42	1.590	36.1	33.5	30.5	27.2	25.9	24.6	22.2	20.5
42-68	1.630	36.1	33.5	30.5	27.2	25.9	24.6	22.2	20.5
68-104	1.750	36.3	33.6	30.9	28.6	27.5	26.6	26.8	24.6
104-150	1.690	34.3	32.5	30.6	28.5	27.2	26.1	26.9	25.2

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
0-17	8.2	7.6	0.24	10.4	1.27	0.14	9	-	-	33.9	3.7	0.8	0.3	38.7
17-42	8.3	7.7	0.23	11.4	0.85	0.09	9	-	-	44.0	4.1	0.5	0.3	48.9
42-68	8.3	7.6	0.23	11.8	0.74	0.09	8	-	-	47.3	4.4	0.5	0.4	52.6
68-104	8.4	7.7	0.25	15.4	0.48	0.01	48	-	-	47.1	4.7	0.4	0.4	52.6
104-150	8.4	7.7	0.26	13.4	0.44	0.05	9	-	-	45.7	5.1	0.5	0.4	51.7

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 %
0-17	-	11.1	38	4.4	-	-	3
17-42	-	13.4	43	3.0	-	-	2
42-68	-	14.2	41	2.6	-	-	3
68-104	-	12.5	35	1.7	-	-	3
104-150	-	14.3	40	1.5	-	-	3

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-17	-	-	-	-	-	-	weak to medium	medium to strong	weak	weak	-	-
17-42	-	-	-	-	-	-	weak to medium	medium to strong	weak	weak	-	-
42-68	-	-	-	-	-	-	weak to medium	medium to strong	weak	weak	-	-
68-104	-	-	-	-	-	-	weak to medium	medium to strong	weak	weak	-	-
104-150	-	-	-	-	-	-	weak to medium	medium to strong	weak	weak	-	-

Profile description

Ah1 0-17 cm	dark reddish brown (5YR 3/3, moist)loam slightly gravelly,moderate fine granular,friable,frequent pedotubules,gradual smooth boundary to,
Ah2 17-42 cm	dark reddish brown (5YR 3/3, moist)clay loam slightly gravelly,moderate fine granular,friable,frequent pedotubules,diffuse smooth boundary to,
AC 42-68 cm	reddish brown (5YR 4/3, moist)clay loam slightly gravelly,weak fine subangular blocky,friable,frequent pedotubules and worm channels,gradual smooth boundary to,
C1 68-104 cm	dark reddish brown (5YR 3/4, moist)clay loam slightly gravelly,weak very fine and fine subangular blocky,friable,gradual smooth boundary to,
C2 104-150 cm	dark reddish brown (5YR 3/4, moist)clay loam slightly gravelly,moderately coherent massive,friable,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Soil Depth	160cm
Texture of parent material	loamy
Weathering Resistance	moderate

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

Major crops	fodder crops
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	seasonally irrigated
Land use or vegetation in the immediate vicinity of the site	high level arable farming
Remarks on Land Use / Vegetation	VEGETATION: LANDUSE: Alfalfa in rotation with other crops (potatoes, maize and lima beans)
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	continuous crop rotation

Altitude	3450m
Physiographic Unit	fan
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	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	well
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

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 23: Phaeozem

Characteristics

Reference soil PE023: Phaeozems

Classification