Reference soil Colombia 14: Andosol

CO014

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 CO014: Andosols

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 ) PARENT MATERIAL: Partly consolidated volcanic ejecta of Quaternary age;

Classification

WRB 2006

WRB 1998

Umbric-Hydric-Silandic- Andosol (Hyperdystric)

Hydri-Silic- Andosol (Umbrihumic Hyperdystric)

0-68 cm

umbric horizon

0-150 cm	andic horizon
0-68 cm	umbric horizon
-	strongly humic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Pachi-Umbric Andosol

Humic Andosol

0-68 cm	umbric A horizon
- cm	umbric A horizon
-	andic
-	strongly humic

0-68 cm	umbric A horizon
-	exchange complex dominated by amorphous material

Other classification

USDA-NRCS (1999)

Vitric Hapludand

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	-	8.4	12.6	12.4	15.3	10.3	59.0	10.6	21.5	32.1	9.0
30-50	-	16.2	18.8	13.9	13.5	7.1	69.5	7.5	12.0	19.5	10.9
50-68	-	3.2	6.8	9.7	17.0	12.9	49.6	12.5	20.8	33.3	17.1
68-98	-	12.6	18.1	14.9	13.4	6.7	65.7	6.2	12.8	19.0	15.4
98-150	-	2.2	4.7	8.5	15.8	11.6	42.8	13.4	23.8	37.2	19.9

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	-	-	-	-	9.0
30-50	-	-	-	-	10.9
50-68	-	-	-	-	17.1
68-98	-	-	-	-	15.4
98-150	-	-	-	-	19.9

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
0-30	5.5	4.3	0.18	-	11.80	0.54	22	3.4	2.4	0.4	0.7	0.4	0.4	1.9
30-50	5.3	4.5	0.10	-	5.30	0.27	20	1.6	1.1	0.7	0.6	0.1	0.0	1.4
50-68	5.5	4.6	0.09	-	7.98	0.38	21	1.3	0.9	1.3	0.7	0.2	0.0	2.2
68-98	5.6	4.9	0.08	-	2.62	0.17	15	0.3	0.2	1.0	0.0	0.1	0.0	1.1
98-150	5.7	4.7	0.08	-	6.52	0.27	24	0.4	0.2	4.0	0.6	0.0	0.0	4.6

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 %
0-30	5	37.2	413	37.8	-	6	1
30-50	7	21.5	197	18.6	-	5	0
50-68	6	35.4	207	26.6	-	3	0
68-98	6	17.0	110	9.2	-	1	0
98-150	14	32.2	162	18.9	-	1	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	10.3	93	-	1.09	0.17	1.46	0.92	1.20	1.10	-	1.49
30-50	10.5	92	-	1.25	0.31	2.02	1.03	0.88	0.70	-	1.87
50-68	10.6	97	-	2.24	0.68	2.00	1.50	1.03	0.82	-	2.03
68-98	10.5	95	-	1.82	0.75	2.20	1.25	0.18	0.37	-	2.00
98-150	10.5	96	-	1.64	0.61	1.85	1.11	0.94	0.76	-	1.79

Profile description

Ah1 0-30 cm	(7.5YR 3/1, moist)sandy loam slightly gravelly,weak fine granular,slightly hard friable non sticky non plastic,many fine coarse pores,few fine gravel rocky fragments,gradual wavy boundary to,
Ah2 30-50 cm	dark brown (7.5YR 3/2, moist)sandy clay loam slightly gravelly,weak fine granular,slightly hard friable slightly sticky slightly plastic,many fine coarse pores,gradual wavy boundary to,
Ahb 50-68 cm	very dark grey (10YR 3/1, moist)loam,porous massive,slightly hard friable slightly sticky slightly plastic weakly smeary,common medium distinct mottles (10 YR 4/4),common fine pores and common pores,clear wavy boundary to,
C 68-98 cm	yellowish brown (10YR 5/6, moist)sandy clay loam,porous massive,slightly hard friable slightly plastic,common fine pores and common pores,clear wavy boundary to,
98-150 cm	(10YR 2.5/1, moist)loam,porous massive,soft very friable slightly sticky plastic moderately smeary,common fine pores and common pores,

Kind 1 (parent material) ; Parker (eds), 1984	ejecta ash
Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	partly consolidated Quaternary volcanic ejecta

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Montane grassland with shrubs and herbs LANDUSE:

Altitude	3810m
Physiographic Unit	N slope 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	38%
Slope Aspect	north
Form of the slope surrounding the site	straight
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
Average size of stone	25
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	stony

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Reference soil Colombia 14: Andosol

Characteristics

Reference soil CO014: Andosols

Classification