Reference soil Ecuador 18: Andosol

EC018

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 EC018: Andosols

EC18 is comparable to profile Ecuador 1 in part III: tour guide for Ecuador of the sixth international soil classification workshop (1984). The profile has been resampled in Mau 1987 by G.del Posso, additionally two monoliths of 140cm length has been taken. The gravelly ash/pumice layer hampers rootdevelopment, however a few roots are visible below the gravel layer, hence effective soil depth is somewhat deeper than 75cm. The soil horizon just above the gravel layer has compacted, probably due to tillage practices.

Classification

WRB 2006

WRB 1998

Mollic-Vitric- Andosol (Eutric)

Pachi-Vitric- Andosol (Mollic Eutric)

0-73 cm	mollic horizon
-	vitric

0-73 cm	mollic horizon
19-73 cm	vitric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Molli-Vitric Andosol

Mollic Andosol

0-73 cm	mollic A horizon
-	andic

0-73 cm	mollic A horizon
-	exchange complex dominated by amorphous material

Local classification:	Suelo negro andino

Other classification

USDA-SCS (1975)

Eutrandept 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
0-19	0	2.7	8.3	13.9	19.8	13.9	58.6	13.1	21.5	34.6	6.8
19-50	0	3.4	8.7	13.7	20.0	13.2	59.0	12.5	20.8	33.3	7.7
50-73	14	7.0	14.0	15.6	18.1	13.4	68.1	12.7	14.4	27.1	4.9
73-85	42	22.2	32.2	26.0	7.1	2.6	90.1	2.6	5.8	8.4	1.5
85-116	0	1.8	7.3	9.6	16.7	14.2	49.6	15.9	26.8	42.7	7.8
116-148	0	2.5	7.9	13.7	21.1	12.2	57.4	13.6	20.9	34.5	8.1

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-19	-	-	-	2.3	6.8
20-50	1.120	-	-	-	-
19-50	-	-	-	3.4	7.7
65-85	1.210	-	-	-	-
50-73	-	-	-	4.0	4.9
73-85	-	-	-	1.0	1.5
85-116	-	-	-	5.4	7.8
116-148	-	-	-	5.4	8.1

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
20-50	1.120	54.0	52.6	45.3	35.5	29.9	23.3	11.1	9.0
65-85	1.210	51.3	49.9	45.1	37.7	33.2	26.2	4.9	3.9

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
0-19	6.7	5.4	0.08	0.7	2.48	0.23	11	-	-	5.8	1.0	0.7	0.0	7.5
19-50	6.7	5.4	0.07	0.8	2.21	0.19	12	-	-	6.9	1.3	0.3	0.1	8.6
50-73	7.0	5.5	0.06	0.4	1.85	0.17	11	-	-	6.5	1.5	0.2	0.1	8.3
73-85	7.6	5.1	0.03	0.3	0.22	0.03	7	-	-	2.2	0.7	0.1	0.1	3.1
85-116	6.7	5.3	0.05	0.5	1.04	0.07	15	-	-	5.5	1.4	0.3	0.2	7.4
116-148	6.8	5.5	0.08	0.6	1.01	0.07	14	-	-	6.1	1.6	0.4	0.5	8.6

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 %
0-19	75	10.0	147	8.8	-	-	0
19-50	86	10.0	130	7.7	-	-	1
50-73	86	9.6	196	6.7	-	-	1
73-85	89	3.5	233	0.8	-	-	3
85-116	85	8.7	112	3.6	-	-	2
116-148	91	9.4	-	3.5	-	-	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
0-19	-	23	-	0.30	0.20	0.40	0.20	0.10	0.20	-	0.30
19-50	-	28	-	0.50	0.20	0.40	0.20	0.10	0.20	-	0.30
50-73	-	30	-	0.60	0.30	0.50	0.20	0.10	0.20	-	0.30
73-85	-	5	-	0.10	0.10	0.30	0.00	0.00	0.00	-	0.10
85-116	-	15	-	0.30	0.20	0.50	0.10	0.10	0.10	-	0.20
116-148	-	9	-	0.20	0.10	0.60	0.10	0.00	0.10	-	0.20

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-19	-	medium to strong	-	-	-	-	-	-	weak	-	-	-
19-50	-	medium to strong	-	-	-	-	-	-	weak	-	-	-
50-73	-	medium to strong	-	-	-	-	-	-	weak	-	-	-
73-85	-	medium to strong	-	-	weak	-	-	-	weak	-	-	-
85-116	-	medium to strong	-	-	weak	-	-	-	weak	-	-	-
116-148	-	medium to strong	-	-	weak	-	-	-	weak	-	-	-

Profile description

Ah1 0-19 cm	dark greyish brown (10YR 4/2, dry) black (10YR 2/1, moist)fine sandy loam,weak very fine and fine granular,slightly hard very friable non sticky non plastic,common very fine tubular pores,abrupt smooth boundary to,
Ah2 19-50 cm	very dark brown (10YR 2/2, moist)fine sandy loam,weak medium angular blocky,soft very friable non sticky non plastic,many very fine tubular pores and few tubular pores,broken massive weakly cemented plough pan pans,gradual smooth boundary to,
AC 50-73 cm	(10YR 2/no, moist)sandy loam gravelly,weak medium and coarse subangular blocky,soft very friable non sticky non plastic,few very fine fine tubular pores and few tubular pores,abrupt wavy boundary to,
2C 73-85 cm	dark yellowish brown (10YR 4/4, moist)coarse sand very gravelly,structureless single grain,loose loose non sticky non plastic,many very fine fine interstitial pores,abrupt wavy boundary to,
3Ab1 85-116 cm	black (10YR 2/1, moist)fine sandy loam,weak medium and coarse subangular blocky and weak medium and coarse granular,slightly hard friable non sticky non plastic,common very fine fine tubular pores and few tubular pores,diffuse wavy boundary to,
3Ab2 116-148 cm	very dark brown (10YR 2/2, moist)fine sandy loam,weak medium subangular blocky,slightly hard friable non sticky non plastic,common very fine fine tubular pores and few tubular pores,

Depth1	73cm
Kind 1 (parent material) ; Parker (eds), 1984	acidic ash
Kind 2 (parent material) (second entry); Parker (eds), 1984	acidic ash
Mode of accumulation or deposition of parent material	ejecta ash
Mode of accumulation or deposition of parent material (second entry)	ejecta ash
Remarks on Parent Materials	mixed ash deposits
Soil Depth	75cm
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	slight
Intensity of the soil erosion type (second entry)	slight
Soil erosion type	sheet
Soil erosion type (second entry)	rill

Major crops	wheat
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	land improvements - not specified
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	no irrigation
Land use or vegetation in the immediate vicinity of the site	medium level arable farming
Remarks on Land Use / Vegetation	VEGETATION: LANDUSE: Also barley and potatoes
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	continuous crop rotation
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)	grassland

Altitude	3200m
Physiographic Unit	low hill in interandean valley
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.	mountain
Slope	10%
Slope Aspect	east-north-east
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	well
Flooding frequency (FAO, 1986)	never
Moist From - To	0-140cm
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
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 18: Andosol

Characteristics

Reference soil EC018: Andosols

Classification