Reference soil Ecuador 02: Andosol

EC002

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)

EC02 is comparable to profile Ecuador6 in: part III - tour guide for Ecuador of the sixth international soil classification workshop (1984). The soil is a true volcanic ash soil, however the bulk density is too high for the required critera of Soil Taxonomy and FAO.

WRB 2006:

WRB 1998:

Umbric Vitric Andosol

Pachi- Vitric Andosol(Umbric)

0-79 cm umbric horizon	umbric horizon
	vitric properties

0-200 cm	vitric horizon
0-79 cm	umbric horizon

FAO-UNESCO-ISRIC 1988:

FAO-UNESCO 1974:

Umbrihumi-

Vitric Andosol

Humic Andosol

0-79 cm	umbric A horizon
	andic properties
	strongly humic

0-79 cm	umbric A horizon
	exchange complex dominated by amorphous material
	smeary consistence

Other classification

Classification (other)

Suelo Negro Andino

Location:

Pinchincha, Quito, INIAP Experimental Station St. Catalina

More images

Physical

Particle size distribution:

Depth (cm)		Gravel (%)	Very Coarse Sand (%)	Coarse Sand (%)	Medium Sand (%)	Fine Sand (%)	Very Fine Sand (%)	Total Sand (%)	Coarse Silt (%)	Fine Silt (%)	Total Silt (%)	Clay (%)
0-10	:	0	0.6	3.1	9.0	15.4	12.2	40.3	16.0	31.8	47.8	11.9
10-55	:	0	0.7	3.0	7.7	15.8	12.8	40.0	16.1	31.0	47.1	12.9
55-79	:	0	3.4	5.9	10.3	16.5	11.5	47.6	14.9	24.4	39.3	13.2
79-96	:	36	3.4	6.2	9.6	16.3	11.7	47.2	12.9	26.3	39.2	13.5
96-165	:	0	0.8	2.9	6.2	15.5	12.9	38.3	19.1	27.3	46.4	15.2
165-200	:	24	2.0	5.0	6.4	13.3	11.6	38.3	12.6	27.0	39.6	22.1

Water retention characteristics

Depth (cm)		Bulk Density (kg/dm³)	pF 0 (% w/v)	pF 1.0 (% w/v)	pF 1.5 (% w/v)	pF 2.0 (% w/v)	pF 2.3 (% w/v)	pF 2.7 (% w/v)	pF 3.4 (% w/v)	pF 4.2 (% w/v)	pF 2.5 (%)
30-50	:	1.040	55.4	55.4	52.9	50.3	48.7	45.9	32.1	27.5	-
80-100	:	1.020	54.7	54.7	52.8	48.1	45.8	42.2	36.8	32.3	-

Other physical data

Depth (cm)		Bulk Density (kg/dm³)	Spec. Surf. Area (m2/g)	COLE (cm/cm)	Water Disp. Clay (%)	Clay (%)
0-10	:	-	-	-	8.9	11.9
10-55	:	-	-	-	7.6	12.9
55-79	:	-	-	-	7.0	13.2
79-96	:	-	-	-	6.2	13.5
96-165	:	-	-	-	14.5	15.2
165-200	:	-	-	-	17.2	22.1

Chemical characteristics:

Depth (cm)		pH H2O	pH KCl	EC 1 : 2.5 (mS/cm)	CaCO3 (%)	Org. C (%)	Org. N (%)	C / N	Exch. Acid (cmol/kg)	Exch. Al (cmol/kg)	Ca (cmol/kg)	Mg (cmol/kg)	K (cmol/kg)	Na (cmol/kg)	Sum Cations (cmol/kg)
0-10	:	4.9	4.4	0.34	-	6.21	0.50	12	-	-	3.4	0.7	1.0	0.0	5.1
10-55	:	5.4	4.5	0.08	-	4.90	0.39	13	-	-	3.7	0.3	0.2	0.0	4.2
55-79	:	6.0	4.7	0.03	-	5.23	0.35	15	-	-	5.7	0.7	0.1	0.0	6.5
79-96	:	6.2	4.8	0.02	-	4.62	0.35	13	-	-	5.8	0.8	0.1	0.1	6.8
96-165	:	6.3	4.8	0.02	-	3.86	0.25	15	-	-	6.6	1.1	0.3	0.1	8.1
165-200	:	6.3	4.8	0.03	-	3.90	0.22	18	-	-	11.2	2.2	1.3	0.4	15.1

Depth (cm)		CEC Soil (cmol/kg)	CEC Clay (cmol/kg)	CEC Org (cmol/kg)	ECEC (cmol/kg)	Base sat. (%)	Al sat. (%)	ESP (%)
0-10	:	18.4	-	21.7	-	28	-	0
10-55	:	13.3	-	17.2	-	32	-	0
55-79	:	14.8	-	18.3	-	44	-	0
79-96	:	14.0	-	16.1	-	49	-	1
96-165	:	14.4	-	13.7	-	56	-	1
165-200	:	19.3	-	13.7	-	78	-	2

Depth (cm)		pH NaF	P Retention (%)	ODOE	Melanic Index	Fe o (wt%)	Al o (wt%)	Si o (wt%)	Fe d (wt%)	Al d (wt%)	Fe p (wt%)	Al p (wt%)	C p (wt%)
0-10	:	10.1	73	-	-	0.60	1.00	0.30	0.70	0.60	0.40	0.50	-
10-55	:	10.2	73	-	-	0.50	1.10	0.40	0.70	0.50	0.30	0.50	-
55-79	:	10.2	79	-	-	0.50	1.30	0.60	0.70	0.50	0.30	0.40	-
79-96	:	10.1	77	-	-	0.50	1.40	0.80	0.70	0.50	0.30	0.40	-
96-165	:	9.8	68	-	-	0.50	1.40	0.80	0.90	0.40	0.30	0.30	-
165-200	:	8.5	82	-	-	0.70	1.00	0.60	1.20	0.50	0.40	0.20	-

Clay mineralogy:

Depth (cm)		Kaolinite	Mica / illite	Vermiculite	Chlorite	Smec	Halloysite	Mixed layer	Quar	Feldspar	Gibbsite	Goethite	Hematite
0-10	:	-	-	-	-	-	-	weak	-	weak	-	-	-
10-55	:	-	-	-	-	-	weak	weak	-	weak	-	-	-
55-79	:	-	-	-	-	-	very weak	weak	-	weak	-	-	-
79-96	:	-	-	-	-	-	-	weak	-	weak	-	-	-
96-165	:	-	-	-	-	-	medium to strong	weak	-	weak	-	-	-
165-200	:	-	-	-	-	-	medium to strong	weak	-	weak	-	-	-

Profile description:

Ah1 0-10 cm	black (10YR 2/1, moist), loam, moderate medium and coarse granular, friable non sticky non plastic, many very fine interstitial pores and few pores, diffuse smooth boundary to,
Ah2 10-55 cm	(10YR 2/no, moist), loam, moderate fine subangular blocky, friable slightly sticky slightly plastic, many very fine tubular pores and few tubular pores, diffuse smooth boundary to,
Ah3 55-79 cm	(10YR 2/no, moist), loam, moderate fine subangular blocky, friable slightly sticky slightly plastic, many very fine tubular pores and few tubular pores, very few medium gravel weathered pumice gravel fragments, gradual wavy boundary to,
2Ab1 79-96 cm	black (10YR 2/1, moist), loam gravelly, weak fine subangular blocky, friable slightly sticky slightly plastic, many very fine tubular pores and few tubular pores, frequent medium gravel weathered pumice gravel fragments, clear wavy boundary to,
2Ab2 96-165 cm	black (10YR 2/1, moist), loam, weak fine subangular blocky, friable slightly sticky slightly plastic, many very fine tubular pores and few tubular pores, clear wavy boundary to,
2Ab3 165-185 cm	(10YR 2/no, moist), silt loam slightly gravelly, weak fine subangular blocky, friable slightly sticky slightly plastic, many very fine tubular pores and few tubular pores, very few medium gravel weathered pumice gravel fragments

The main parent rock/ material over which the soil has been formed (1st entry)	ejecta ash
Mode of Accumulation or deposition of parent material (1st entry)	ejecta ash

Current land use at the site	high level mixed farming
Major crops	cereals (unspecified)
Main type of irrigation	no irrigation
Rotation scheme	crop - grass rotation, lay
Remarks on Land Use / Vegetation	Vegetation: experimental station Land use:

The altitude of the soil profile relative to mean sea level, specified in meters	3140 m asl
Regional landform	mountain
Topography of the surrounding country	rolling
Physiographic Unit in the immediate surrounding of the site	footslopes of volcano range
The slope refers to the inclination of the land immediately surrounding the site. The measured or estimated slope angle is specified to the nearest per cent	12 %
The physiographic position of the site where the profile is located	middle slope
Form of the slope surrounding the site	convex

Kind of groundwater table	no groundwater table observed
Runoff	rapid
Flooding frequency	never
Drainage Class	well

Rockiness	none
Stoniness	none
Cracks	no cracks observed
Slaking of aggregates by tillage, rainfall or frost	no surface slaking/crusting observed
Evidence of salt	non-saline
Evidence of alkali	non-alkaline

Soil erosion type (1st entry)
Occurrence of soil aggradation
Slope Stability

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Reference soil Ecuador 02: Andosol

Characteristics