Reference soil Ecuador 19: Andosol

EC019

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)

Reference soil EC019: Andosols

EC19 is comparable to profile Ecuador 2 in part III: excursion guide for Ecuador of the sixth International Soil Classification workshop (1984). In may 1987 this profile has been redescribed and resampled, additionally two monoliths has been taken. The climate is ustic bordering to aridic. Except for one month rainfall is always lower than the evapotranspiration.

Classification

WRB 2006

WRB 1998

Vitric- Andosol (Calcaric)

Calcari-Vitric- Andosol

vitric

0-130 cm	vitric horizon
0-88 cm	ochric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Vitric Andosol

Ochric Andosol

0-88 cm	ochric A horizon
-	andic

0-88 cm	ochric A horizon
-	exchange complex dominated by amorphous material

Local classification:	Suelo de duna

Other classification

USDA-SCS (1975)

Vitrandept ustic 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
0-50	0	0.0	0.1	1.5	20.0	35.6	57.2	24.9	14.0	38.9	4.0
50-88	0	0.0	0.2	1.5	20.0	36.6	58.3	25.4	12.8	38.2	3.5
88-130	0	0.1	0.3	1.9	20.8	48.7	71.8	18.8	6.7	25.5	2.8
130-170	0	0.3	0.4	2.6	16.5	36.7	56.5	26.9	13.8	40.7	2.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-50	-	-	-	1.0	4.0
50-88	-	-	-	2.8	3.5
88-130	-	-	-	0.0	2.8
130-170	-	-	-	2.5	2.8

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
0-50	6.6	5.7	0.04	0.7	1.00	0.10	10	-	-	4.1	1.9	0.4	0.0	6.4
50-88	7.4	6.1	0.05	3.5	0.57	0.04	14	-	-	4.4	2.0	0.4	0.2	7.0
88-130	7.9	6.5	0.08	3.1	0.41	0.03	14	-	-	4.7	2.4	0.3	0.2	7.6
130-170	8.9	8.1	0.25	3.2	0.33	0.02	17	-	-	17.6	3.6	1.0	0.4	22.6

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 %
0-50	96	6.7	168	3.5	-	-	0
50-88	109	6.4	183	2.1	-	-	3
88-130	138	5.5	196	1.4	-	-	4
130-170	-	8.7	311	1.1	-	-	5

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
0-50	-	18	-	0.40	0.30	0.40	0.10	0.00	0.10	-	0.20
50-88	-	13	-	0.30	0.20	0.40	0.10	0.00	0.00	-	0.20
88-130	-	13	-	0.30	0.20	0.40	0.10	0.00	0.00	-	0.30
130-170	-	13	-	0.20	0.10	0.40	0.10	0.00	0.00	-	0.10

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-50	-	medium to strong	-	-	-	-	-	-	weak	-	-	-
50-88	-	medium to strong	-	-	-	-	-	-	weak	-	-	-
88-130	-	medium to strong	-	-	-	-	-	-	weak	-	-	-
130-170	-	medium to strong	-	-	-	-	-	-	weak	-	-	-

Profile description

Ah1 0-50 cm	(10YR 2/4, dry) black (10YR 2/1, moist)fine sandy loam,weakly coherent porous massive,soft very friable non sticky non plastic,few very fine tubular pores and many interstitial pores,diffuse smooth boundary to,
Ah2 50-88 cm	very dark brown (10YR 2/2, moist)fine sandy loam,weakly coherent porous massive,very friable non sticky non plastic,few very fine tubular pores and few interstitial pores,gradual smooth boundary to,
CA 88-130 cm	very dark greyish brown (10YR 3/2, moist)fine sandy loam,moderately coherent porous massive,friable non sticky non plastic,few very fine Y pores and many interstitial pores,abrupt wavy boundary to,
2C 130-170 cm	dark yellowish brown (10YR 3/4, moist)fine sandy loam gravelly,strongly coherent porous massive,firm non sticky non plastic,few very fine tubular pores and few interstitial pores,clear boundary to,
2C 130-170 cm	unweath.TUFF fragments

Depth1	130cm
Kind 1 (parent material) ; Parker (eds), 1984	ejecta ash
Kind 2 (parent material) (second entry); Parker (eds), 1984	ejecta ash
Mode of accumulation or deposition of parent material	eolian sand
Mode of accumulation or deposition of parent material (second entry)	ejecta ash
Remarks on Parent Materials	intermediate ash
Soil Depth	130cm
Texture of parent material	sandy
Texture of parent material (second entry)	sandy
Weathering Resistance	poor
Weathering Resistance (second entry)	poor
General characterization of the status of weathering of solid rock	slightly
General characterization of the status of weathering of solid rock (second entry)	slightly

Intensity of the soil erosion type	severe
Soil erosion type	wind

Land use or vegetation in the immediate vicinity of the site	(semi-)natural vegetation
Remarks on Land Use / Vegetation	VEGETATION: Clumps of Stipa spp. with bare soil LANDUSE:
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	degraded
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	short grassland

Altitude	2780m
Physiographic Unit	eroded dunes
Physiographic position of the site	middle slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	dune field
Slope	13%
Slope Aspect	south-west
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
Dry From - To	0-50cm
Flooding frequency (FAO, 1986)	never
Moist From - To	50-170cm
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	rapid

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
Microrelief Height: variation in height	50
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	coppice mounds
Microrelief pattern	reticulate
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 Ecuador 19: Andosol

Characteristics

Reference soil EC019: Andosols

Classification