Reference soil Colombia 12: Andosol

CO012

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 CO012: Andosols

PARENT ROCK: Ejecta of 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 surroundings also maize, potatoes, onions, Eucalyptus and Pinus. The original vegetation (bosque humido montano (secco) bayo) has been cleared. ADDITIONAL NOTES ON PROFILE DESCRIPTION: Ah1 - reaction to NaF = 10; also many coarse roots; Ah2 - mottles occur along rootchannels; also many coarse roots; reaction to NaF = 10; lower boundary in places clear; AC - reaction to NaF = 10; C1 - reaction to NaF = 9.8; C2 - depth C2 may attain 15 m; little evidence of fauna activity in the soil; some tubules; pH relatively high because of lower elevation, less rain and higher temperature; * volcanic glass determination is preliminary and needs minerological confirmation, the term is used to describe the quantity of visible minerals in the soil in general.

Classification

WRB 2006

WRB 1998

Umbric-Silandic- Andosol (Hyperdystric)

Umbrihumi-Silic- Andosol (Hyperdystric)

0-88 cm	umbric horizon
-	andic

0-150 cm	andic horizon
0-88 cm	umbric horizon
-	strongly humic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Pachi-Umbric Andosol

Humic Andosol

0-88 cm	umbric A horizon
- cm	umbric A horizon
-	andic
-	strongly humic

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

Other classification

USDA-NRCS (1999)

Humic Udivitrand

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	-	0.8	3.5	20.2	19.3	9.6	53.4	8.3	19.3	27.6	19.0
30-65	-	0.1	2.5	27.6	21.0	7.6	58.8	5.8	16.2	22.0	19.1
65-88	-	0.1	0.4	2.7	11.1	10.4	24.7	5.7	27.1	32.8	42.6
88-108	-	0.1	0.7	3.2	8.8	6.7	19.5	7.7	33.0	40.7	39.9
108-150	-	0.1	0.7	4.3	8.9	6.2	20.2	9.3	35.5	44.8	35.0

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
11-17	0.480	-	-	-	-
0-30	-	-	-	-	19.0
30-65	-	-	-	-	19.1
45-52	0.720	-	-	-	-
71-78	0.520	-	-	-	-
65-88	-	-	-	-	42.6
88-108	-	-	-	-	39.9
113-120	0.480	-	-	-	-
108-150	-	-	-	-	35.0

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
11-17	0.480	71.9	67.9	59.5	45.4	40.3	36.6	26.7	25.8
45-52	0.720	64.4	63.3	57.9	50.9	46.7	43.1	35.7	34.4
71-78	0.520	75.6	75.0	69.4	63.3	59.9	56.8	49.0	47.4
113-120	0.480	76.2	76.2	70.3	60.7	55.5	52.3	43.3	41.0

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	4.8	4.3	0.18	-	15.88	0.16	99	3.6	0.7	0.6	0.5	0.1	0.0	1.2
30-65	5.5	4.7	0.06	-	9.31	0.53	18	0.8	0.2	1.3	0.5	0.0	0.0	1.8
65-88	5.7	4.8	0.05	-	11.20	0.29	39	0.4	0	0.8	0.7	0.2	0.7	2.4
88-108	5.8	5.3	0.03	-	1.92	-	-	0.1	0	0.8	0.7	0.0	0.0	1.5
108-150	6.1	5.3	0.03	-	1.26	0.09	14	0	0	1.6	1.3	0.1	0.0	3.0

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	2	61.7	325	55.6	-	1	0
30-65	4	46.9	246	32.6	-	0	0
65-88	3	76.0	178	39.2	-	0	1
88-108	3	47.2	118	6.7	-	0	0
108-150	7	45.7	131	4.4	-	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	10.8	99	-	3.87	0.72	1.02	2.34	0.54	2.13	-	0.70
30-65	10.9	99	-	3.96	1.18	0.83	1.66	0.33	1.27	-	0.61
65-88	10.8	100	-	8.63	3.18	1.50	3.26	0.41	1.22	-	1.17
88-108	10.6	100	-	9.70	5.49	2.23	2.08	0.02	0.32	-	1.59
108-150	10.5	100	-	10.50	6.16	2.44	1.33	0.01	0.28	-	1.66

Profile description

Ah1 0-30 cm	dark brown (7.5YR 3/2, moist)loam,weak fine and medium granular,slightly hard friable non sticky non plastic,many fine coarse tubular pores,few volcanic glass fragments,gradual smooth boundary to,
Ah2 30-65 cm	(7.5YR 2.5/no, moist)sandy loam,weak fine and medium subangular blocky,slightly hard very friable slightly sticky non plastic,few fine faint diffuse mottles (5 YR 3/4),many fine coarse tubular pores,very frequent volcanic glass fragments,gradual smooth boundary to,
AC 65-88 cm	very dark grey (10YR 3/1, moist)sandy loam,weak fine and medium subangular blocky,slightly hard very friable slightly sticky non plastic,many fine coarse pores,frequent volcanic glass fragments,gradual smooth boundary to,
C1 88-108 cm	yellowish brown (10YR 5/6, moist)clay loam,porous massive,slightly hard very friable slightly sticky non plastic,common pores,few volcanic glass fragments,gradual smooth boundary to,
C2 108-150 cm	yellowish brown (10YR 5/8, moist)sandy loam,porous massive,soft very friable non sticky non plastic,common pores,few volcanic glass few rock fragments,

Kind 1 (parent material) ; Parker (eds), 1984	ejecta ash
Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	andesitic ash/tuff of Galeras volcano

Major crops	sisal
Land use or vegetation in the immediate vicinity of the site	medium level arable farming
Remarks on Land Use / Vegetation	VEGETATION: Original vegetation (bosque humido montano (secco) bayo) has been cleared LANDUSE: In the surroundings also maize, potatoes, onions, Eucalyptus and Pinus

Altitude	2350m
Physiographic Unit	footslope of Galeras volcano
Physiographic position of the site	upper slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	volcano
Slope	12%
Slope Aspect	east-south-east
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	steeply dissected

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)	very rapid

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil Colombia 12: Andosol

Characteristics

Reference soil CO012: Andosols

Classification