Reference soil Nicaragua 05: Andosol

NI005

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 NI005: Andosols

Shallow, young, (somewhat) excessively drained, black loamy sand soil developed from volcanic ejecta, derived from unconsolidated pyroclastic rock (ash, lapilli, volcanic bombs). The soil contains fresh pyroclastic fragments, is weakly structured, highly porous and highly erodable. At the surface an accumulation of about 2 cm of organic material is found. The densily closed natural vegetation prevents soil erosion. The profile forms part of the NIC05 to NIC09 toposequence.

Classification

WRB 2006

WRB 1998

Mollic-Epileptic-Vitric- Andosol (Arenic)

Molli-Vitric- Andosol (Epileptic)

0-30 cm	mollic horizon
-	continuous rock
-	vitric

0-30 cm	vitric horizon
0-30 cm	mollic horizon
-	continuous hard rock

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Molli-Vitric Andosol lithic

Mollic Andosol lithic

0-30 cm	mollic A horizon
- cm	mollic A horizon
-	andic
-	continuous hard rock

0-30 cm	mollic A horizon
-	exchange complex dominated by amorphous material

Other classification

USDA-NRCS (1999)	Mollic Ustivitrand
USDA-SCS (1975)	Mollic Vitrandept ustic ashy halloysitic isohyperthermic

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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
0-10	-	33.5	21.8	9.0	10.7	3.8	78.8	8.8	5.9	14.7	6.4
10-30	-	29.0	27.4	10.5	10.1	4.8	81.8	6.3	6.3	12.6	5.5

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-10	0.903	-	-	6.6	6.4
10-30	0.937	-	-	2.5	5.5

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
0-10	0.903	54.9	39.3	36.0	26.8	22.6	19.9	11.6	10.8
10-30	0.937	48.0	25.3	22.2	15.2	12.9	10.8	7.0	6.7

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
0-10	6.3	5.6	0.00	-	3.07	0.36	9	-	-	12.4	1.7	0.5	0.0	14.6
10-30	6.5	5.7	0.05	1.3	2.42	0.24	10	-	-	12.7	1.7	0.4	0.0	14.8

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 %
0-10	81	18.0	281	10.7	-	-	0
10-30	87	17.0	309	8.5	-	-	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
0-10	8.8	34	-	0.79	0.50	-	-	-	-	-	1.23
10-30	8.0	36	-	0.86	0.51	-	-	-	-	-	1.25

Depth (cm)	CaSO4.2H2O %	P Bray mg/kg	P Olsen mg/kg	pH CaCl2	clay_noncarbonate % w/w	clay_carbonate % w/w	phosphorus4 mg/kg	phosphorus1 mg/kg	total_sulfur % w/w
0-10	-	-	2.3	-	-	-	-	-	-
10-30	-	-	1.2	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-10	-	-	-	-	very weak	-	-	-	-	-	-	-
10-30	-	-	-	-	very weak	-	-	-	-	-	-	-

Profile description

Ah 0-10 cm	black (10YR 2/1, moist)loamy sand leaves moderately,weak fine and medium granular,soft very friable,many fine continuous exped tubular random pores and many continuous exped tubular random pores highly porous (>60 vol%),frequent fine gravel fresh pyroclastic few medium gravel fresh pyroclastic fragments,clear smooth boundary to,
AC 10-30 cm	very dark greyish brown (10YR 3/2, moist)loamy sand,weakly coherent,loose,many fine continuous exped tubular random pores highly porous (>60 vol%),frequent fine gravel fresh pyroclastic few medium gravel fresh pyroclastic fragments,abrupt wavy boundary to,

Depth1	30cm
Kind 1 (parent material) ; Parker (eds), 1984	pyroclastic, unconsolidated
Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	origin about 1770
Soil Depth	30cm
Texture of parent material	gravelly
Texture of parent material (second entry)	gravelly
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	slightly

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Slope stability	stable

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	non-agricultural land
Remarks on Land Use / Vegetation	VEGETATION: Ultimate phase of primary vegetation succession
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	semi-deciduous forest

Altitude	250m
Physiographic Unit	Pacific Volcanic Cordillera
Physiographic position of the site	middle slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	caldera
Slope	15%
Slope Aspect	west
Form of the slope surrounding the site	concave
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-30cm
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	medium
Drainage class - intergrade; FAO (2006) - Guidelines for soil description	excessive

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
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	level
Microrelief pattern	none
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 Nicaragua 05: Andosol

Characteristics

Reference soil NI005: Andosols

Classification