Reference soil Ecuador 03: Andosol

EC003

Andosols occur throughout the world where volcanic activity is common, especially in the circum-Pacific region and along the mid-Atlantic Ridge.

Characteristics

Soils with a vitric or andic horizon (slightly to moderately weathered horizons in pyroclastic deposits dominated by short-range-order minerals, notably allophane and imogolite) starting within 25 cm from the soil surface. In addition, they may have a histic, fulvic, melanic, mollic, umbric, ochric, duric, or cambic horizon. Other diagnostic horizons (unless buried deeper than 50 cm by volcanic deposits) are absent.

Distribution of Andosols (rough estimation supplied by soilgrids)

EC03 is comparable to profile Ecuador 8 in part III: tour guide for Ecuador of the sixth international soil classification workshop (1984). The soil was redescribed and resampled by Kauffman and del Posso in April 1987; additionally two monoliths of 140cm length were taken. There are not sufficient temperature data available at the altitude of the site. When a correction of 6 degrees celsius per 1000 metre is applied on the data of Izobamba meteo station, the average annual temperature is around the limit of 8 degree celsius, hence mesic to frigid. If the frigid temperature regime is rejected the soil will key out as Dystrandept. The soil is a true volcanic ash soil except for the bulk density, which is slightly too high. If the bulk density criterion is strictly applied the soil will classify as Andic Humitropept(ST) and as humic Cambisol(FAO).

Classification

WRB 2006

Vitric Umbric Andosols (Endoskeletic )

0-92	umbric horizon
-	vitric horizon

WRB 1998

Vitric Pachi Umbric Endoskeletic Andosols

0-92 cm	vitric horizon
0-92 cm	umbric horizon

FAO-UNESCO-ISRIC 1974

Humic Andosols

-	exchange complex dominated by amorphous material horizon
-	smeary consistence horizon
0-92 cm	umbric A horizon

Local classification

Classification information	Suelo Negro Andino

Other classification

USDA-SCS (1975)	Dystrandept udic loamy mixed isomesic

Location:

Pinchincha, Quito, El Corazon vulcano

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Physical characteristics

Particle size distribution

Depth (cm)	Clay % weight/weight	coarse sand % weight/weight	coarse silt % weight/weight	fine sand % weight/weight	fine silt % weight/weight	Gravel % volume/volume	medium sand % weight/weight	Total sand % weight/weight	Total silt % weight/weight	very coarse sand % weight/weight	very fine sand % weight/weight
0-26	8.2	8.6	13.8	19.4	20.4	0	17.2	57.6	34.2	1.2	11.2
26-63	10.4	9.0	13.5	18.6	20.4	0	14.4	55.7	33.9	2.2	11.5
63-92	9.5	14.9	11.6	16.4	13.4	28	17.0	65.5	25.0	5.3	11.9
92-134	1.1	38.0	0.1	6.4	1.9	47	28.3	96.9	2.0	23.7	0.5
134-182	10.8	4.8	16.6	16.9	28.4	0	8.4	44.3	45.0	0.5	13.7

Water retention characteristic

Depth (cm)	Bulk density kg/dm³	pF 0 % volume/volume	pF 1.0 % volume/volume	pF 1.5 % volume/volume	pF 2.0 % volume/volume	pF 2.3 % volume/volume	pF 2.7 % volume/volume	pF 3.4 % volume/volume	pF 4.2 % volume/volume
10-30	0.880	61.3	61.1	61.3	56.5	53.9	49.7	34.1	29.0
30-50	0.970	58.3	58.3	58.1	52.4	49.7	45.0	39.6	33.9
80-100	0.840	57.9	54.2	49.5	44.7	41.7	34.7	6.1	5.1

Other physical data

Depth (cm)	Bulk density kg/dm³	Clay % weight/weight	COLE cm/cm	Spec. Surf. Area m²/g	Water disp. clay %
10-30	0.880	-	-	-	-
0-26	-	8.2	-	-	2.2
26-63	-	10.4	-	-	9.3
30-50	0.970	-	-	-	-
63-92	-	9.5	-	-	3.7
80-100	0.840	-	-	-	-
92-134	-	1.1	-	-	1.1
134-182	-	10.8	-	-	9.8

Chemical characteristics

Depth (cm)	C % weight/weight	Ca cmol(c)/kg	CaCO3 % weight/weight	C / N unitless	EC 1: 2.5 mS/cm	Exch. Acid cmol(c)/kg	Exch. Al cmol(c)/kg	K cmol(c)/kg	Mg cmol(c)/kg	N %	Na cmol(c)/kg	pH H2O unitless	pHKCl unitless	Sum Cations cmol(c)/kg
0-26	6.14	1.9	-	13	0.04	0.8	0.7	0.2	0.6	0.46	0.0	5.6	4.4	2.7
26-63	5.73	1.9	-	15	0.02	0.3	0.2	0.2	0.6	0.38	0.1	6.0	4.6	2.8
63-92	4.29	3.0	-	14	0.02	0.1	0	0.2	0.8	0.31	0.1	6.4	4.9	4.1
92-134	0.22	0.2	0.3	11	0.02	0.1	0	0.0	0.1	0.02	0.0	6.6	5.0	0.3
134-182	2.80	2.1	0.1	18	0.02	0.1	0	0.1	0.5	0.16	0.1	6.7	4.9	2.8

Depth (cm)	Al sat. %	Base sat. %	CEC clay cmol(c)/kg	CEC org cmol(c)/kg	CEC soil cmol(c)/kg	ECEC cmol(c)/kg	ESP %
0-26	5	20	162	21.4	13.3	-	0
26-63	2	25	107	20.0	11.1	-	1
63-92	0	42	102	15.1	9.7	-	1
92-134	0	38	73	0.8	0.8	-	0
134-182	0	35	73	9.8	7.9	-	1

Depth (cm)	Al d % weight/weight	Al o % weight/weight	Al p % weight/weight	C p % weight/weight	Fe d % weight/weight	Fe o % weight/weight	Fe p % weight/weight	ODOE unitless	pH NaF unitless	P Retention %	Si o % weight/weight
0-26	0.60	0.90	0.40	-	0.70	0.50	0.30	-	10.1	79	0.30
26-63	0.60	1.30	0.40	-	0.90	0.70	0.40	-	10.5	89	0.70
63-92	0.60	1.40	0.50	-	0.90	0.60	0.40	-	10.3	84	0.60
92-134	0.10	0.20	0.10	-	0.30	0.10	0.00	-	8.4	20	0.10
134-182	0.50	1.30	0.40	-	1.00	0.70	0.20	-	10.3	76	0.70

Clay mineralogy

Depth (cm)	Chlorite unitless	Feldspar unitless	Gibbsite unitless	Goethite unitless	Halloysite unitless	Hematite unitless	Kaolinite unitless	Mica / illite unitless	Mixed-layer unitless	Quartz unitless	Smec unitless	Vermiculite unitless
0-26	-	weak	-	-	-	-	-	-	weak	-	-	-
26-63	-	weak	-	-	-	-	-	-	weak	-	-	-
63-92	-	weak	-	-	-	-	-	-	weak	-	-	-
92-134	-	weak	-	-	-	-	-	-	weak	-	weak	-
134-182	-	weak	very weak	weak	-	-	-	-	weak	-	-	-

Profile description

Ah1 0-26 cm	black (10YR 2/1, moist)loam,weak medium subangular blocky,very friable slightly sticky slightly plastic weakly smeary,many very fine fine tubular pores and few tubular pores,diffuse wavy boundary to,
Ah2 26-63 cm	black (10YR 2/1, moist)loam,weak fine and medium subangular blocky,friable slightly sticky slightly plastic weakly smeary,many very fine fine tubular pores,diffuse wavy boundary to,
Ah3 63-92 cm	(10YR 2/no, moist)loam,weak medium subangular blocky,friable slightly sticky slightly plastic weakly smeary,many very fine fine tubular pores,few medium gravel pumice fragments,abrupt wavy boundary to,
2C 92-134 cm	yellowish brown (10YR 5/4, moist)coarse sand gravelly,structureless single grain,loose loose non sticky non plastic,many very fine medium interstitial pores,frequent medium gravel pumice fragments,abrupt wavy boundary to,
3Ab 134-182 cm	black (10YR 2/1, moist)loam,moderately coherent porous massive,friable sticky plastic,many very fine fine tubular pores and common tubular pores,

Mode of accumulation or deposition of parent material	ejecta ash
Weathering Resistance (second entry)	poor
Depth1	92cm
General characterization of the status of weathering of solid rock	slightly
Weathering Resistance	poor
Texture of parent material	loamy
Remarks on Parent Materials	multiple ash/pumice
Soil Depth	92cm
Kind 2 (parent material) (second entry); Parker (eds), 1984	lapilli
Mode of accumulation or deposition of parent material (second entry)	ejecta ash
Kind 1 (parent material) ; Parker (eds), 1984	ejecta ash
Texture of parent material (second entry)	sandy
General characterization of the status of weathering of solid rock (second entry)	slightly

Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Remarks on Land Use / Vegetation	VEGETATION: Stypa ichu (paramo grass) LANDUSE:
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	short grassland
Land use or vegetation in the immediate vicinity of the site	(semi-)natural vegetation

Physiographic Unit	El Corazon volcano
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	mountainous
Physiographic position of the site	upper slope
Altitude	4000m
Slope	45%
Form of the slope surrounding the site	straight
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	volcano
Slope Aspect	north-east

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
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	rapid
Moist From - To	0-180cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none
Surface cracking	no cracks observed

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Reference soil Ecuador 03: Andosol

Characteristics