Reference soil Colombia 11: Andosol

CO011

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 CO011: Andosols

PARENT ROCK: Tertiary-Early Pleistocene lava from Galeras volcano. CLIMATE: The climate may vary considerably over short distances because of varied topography. Calhoen (1971) gives the following information on general climate variations in the Pasto area: altitude (m) rainfall (mm) temperature (Celsius) 3100 9-12 2750 781 13 2670 700 13 1400 1392 20 (0 2849 26) VEGETATION AND LAND USE: In the immediate environment maize, potatoes and beans are cultivated, as well as Eucalyptus and Pinus. In associated lower areas (Alfisols) the cultivation of cereals is common, like wheat and barley. ADDITIONAL NOTES ON PROFILE DESCRIPTION: Ah1 - reaction to NaF = 9.8; AC - krotovinas: diameter 3 cm, ellipsoidal; mottles: whitish, biological; C1 - krotovinas: diameter 3 cm; C3 - inclusions: thin Fe fibers, are too deep to be diagnostic for a placic horizon.

Classification

WRB 2006

WRB 1998

Umbric-Silandic- Andosol (Hyperdystric Thixotropic)

Umbrihumi-Silic- Andosol (Hyperdystric)

0-130 cm	umbric horizon
-	andic

0-130 cm	umbric horizon
0-150 cm	andic horizon
-	strongly humic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Pachi-Umbric Andosol

Humic Andosol

0-130 cm	umbric A horizon
- cm	umbric A horizon
-	andic
-	smeary consistence

0-130 cm	umbric A horizon
-	exchange complex dominated by amorphous material
-	smeary consistence

Other classification

USDA-NRCS (1999)	Humic Udivitrand
USDA-SCS (1975)	Humic Dystrandept udic thixotropic 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
0-30	-	1.1	2.5	6.4	13.5	11.5	35.0	8.7	33.0	41.7	23.3
30-57	-	0.2	1.6	5.5	15.7	10.9	33.9	8.5	25.8	34.3	31.7
57-80	-	0.5	2.8	6.7	13.3	9.6	32.9	9.2	22.3	31.5	35.6
80-130	-	0.1	0.4	2.1	8.5	9.4	20.5	7.7	32.8	40.5	38.9
130-150	-	0.2	1.0	3.2	12.7	8.6	25.7	8.5	23.6	32.1	42.3

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-30	-	-	-	-	23.3
30-57	-	-	-	-	31.7
57-80	-	-	-	-	35.6
80-130	-	-	-	-	38.9
130-150	-	-	-	-	42.3

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
0-30	4.6	4.2	0.96	-	15.40	-	-	3.0	2.2	6.6	0.6	0.2	0.0	7.4
30-57	5.4	4.7	0.22	-	9.78	-	-	0.5	0.4	4.4	1.3	0.1	0.0	5.8
57-80	5.7	4.8	0.09	-	6.33	-	-	0.3	0.2	2.4	0.6	0.2	0.0	3.2
80-130	5.9	4.9	0.06	-	6.50	-	-	0.2	0	3.3	1.6	1.1	0.0	6.0
130-150	6.1	5.2	0.05	-	3.49	-	-	-	0	1.7	1.4	0.3	0.0	3.4

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 %
0-30	11	68.0	292	53.9	-	3	0
30-57	9	64.7	204	34.2	-	1	0
57-80	5	62.0	174	22.2	-	0	0
80-130	9	65.6	169	22.8	-	0	0
130-150	5	74.0	175	12.2	-	0	0

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
0-30	10.6	97	-	3.02	0.82	1.25	2.08	0.91	1.87	-	1.22
30-57	10.5	99	-	6.18	2.35	1.52	2.78	0.80	1.17	-	1.60
57-80	10.3	99	-	6.18	2.68	3.64	6.41	0.59	0.85	-	1.48
80-130	10.2	99	-	6.36	2.89	2.92	3.14	0.85	0.99	-	2.04
130-150	10.0	100	-	10.30	5.72	0.40	1.60	0.24	1.35	-	2.59

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-30	-	weak	-	-	-	-	weak	weak	weak	-	weak	-
30-57	-	weak	-	-	-	-	weak	weak	weak	-	weak	-
57-80	-	weak	-	-	-	-	weak	weak	weak	-	weak	-
80-130	-	weak	-	-	-	-	weak	-	weak	-	weak	-
130-150	-	medium to strong	-	-	-	-	weak	-	-	-	-	-

Profile description

Ah1 0-30 cm	(10YR 2.5/1, moist)loam,strong fine granular and strong medium granular,soft friable non sticky non plastic moderately smeary,many fine coarse pores,very frequent worm channels,gradual smooth boundary to,
Ah2 30-57 cm	(10YR 2.5/1, moist)silt loam,moderate fine subangular blocky and moderate medium subangular blocky,slightly hard friable non sticky non plastic moderately smeary,patchy moderately thick humus cutans,many fine coarse tubular pores,few fine gravel charcoal fragments,very frequent worm channels,gradual smooth boundary to,
AC 57-80 cm	very dark greyish brown (10YR 3/2, moist)clay loam,weak fine and medium subangular blocky,slightly hard friable slightly sticky non plastic,few mottles,broken moderately thick clay and humus cutans,common fine coarse pores,frequent charcoal fragments,frequent krotovinas and worm channels,gradual smooth boundary to,
C1 80-130 cm	dark brown (10YR 3/3, moist)loam,weak fine and medium subangular blocky,soft friable slightly sticky non plastic,common fine coarse pores,few krotovinas,gradual smooth boundary to,
C2 130-150 cm	(dark) brown (7.5YR 4/4, moist)loam,porous massive,soft friable slightly sticky non plastic,common fine coarse pores,
C2 130-150 cm	threadlike ferruginous plates

Kind 1 (parent material) ; Parker (eds), 1984	fine-grained intermediate igneous rock
Remarks on Parent Materials	Tertiary-early Pleistocene andesitic lava from Galeras volcano

Land use or vegetation in the immediate vicinity of the site	cultivated pasture
Remarks on Land Use / Vegetation	VEGETATION: Humid montane forest has been cleared for pasture LANDUSE: In the immediate environment maize, potatoes and beans are cultivated, as well as Eucalyptus and Pinus. In associated lower areas the cultivation of cereals wheat and barley is common.

Altitude	3100m
Physiographic Unit	shoulder
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	lava plain
Slope	8%
Slope Aspect	east-north-east
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

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	high
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface partly slaked, round smooth aggregates
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil Colombia 11: Andosol

Characteristics

Reference soil CO011: Andosols

Classification