Reference soil Nicaragua 10: Andosol

NI010

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 NI010: Andosols

Shallow, (moderately) well drained, dark yellowish brown to (dark) brown silty clay loam to silt loam soil developed from volcanic ejecta, derived from unconsolidated pyroclastic materials. The soil contains fresh talpetate fragments, is weakly to moderately structured and moderately porous. The strongly cemented layers at 23 and 67 cm depth, called "talpetate" (Bm horizon) are in this part of Nicaragua probably of geogenetic and pedogenetic origin. The shallowness of the soil and the drought hazard due to the semi-dry climate determine the selected land use type. The profile forms part of a toposequence (El Crucero- Montelimar) of soils with "talpetate", studied by the Department of Soil Science of the Nicaraguan Agricultural University.

Classification

WRB 2006

WRB 1998

Petroduric-Eutrosilic- Andosol (Siltic)

Petroduri-Eutrisilic- Andosol

23-42 cm	petroduric horizon
-	andic

0-23 cm	ochric horizon
23-42 cm	petroduric horizon
23-67 cm	andic horizon
67-115 cm	vitric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Orthi-Haplic Andosol duripan

Vitric Andosol duripan

0-23 cm	ochric A horizon
- cm	mollic A horizon

0-23 cm	ochric A horizon
- cm	duripan horizon
- cm	mollic A horizon
-	exchange complex dominated by amorphous material

Local classification:	Santo Domingo Series

Other classification

USDA-NRCS (1999)	Entic Durustoll
USDA-SCS (1975)	Entic Durustoll ustic fine-silty 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
0-23	-	0.5	0.8	1.8	6.5	4.3	13.9	9.3	43.6	52.9	33.2
23-42	-	19.4	15.2	9.1	11.2	3.2	58.1	11.0	23.7	34.7	7.2
42-67	-	0.9	2.6	7.2	11.6	7.8	30.1	13.5	36.4	49.9	19.9
67-88	-	0.6	2.1	4.8	10.7	5.8	24	15.4	38.2	53.6	22.4
88-115	-	0.1	0.1	0.5	4.0	5.3	10	12.5	41.4	53.9	36.1
115-115	-	0.1	0.1	0.5	4.4	4.0	9.1	16.0	47.4	63.4	27.5

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-23	0.936	-	-	10.5	33.2
23-42	-	-	-	3.5	7.2
42-67	0.805	-	-	10.2	19.9
67-88	-	-	-	10.4	22.4
88-115	1.070	-	-	14.7	36.1
115-115	-	-	-	12.5	27.5

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
0-23	0.936	62.7	60.6	55.2	47.1	44.9	40.0	32.5	25.2
42-67	0.805	66.2	63.6	56.4	48.6	47.0	43.4	37.9	31.9
88-115	1.070	57.2	55.7	50.0	44.7	43.8	41.1	33.9	31.6

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
0-23	6.4	5.0	0.06	-	4.41	0.42	10	-	-	25.5	5.2	1.7	0.1	32.5
23-42	6.4	5.3	0.06	-	0.34	0.03	11	-	-	13.2	4.3	0.3	1.1	18.9
42-67	6.4	4.9	0.06	-	0.86	0.10	9	-	-	15.0	6.3	0.4	0.2	21.9
67-88	6.3	4.4	0.06	-	0.44	0.05	9	-	-	18.1	10.2	0.2	0.3	28.8
88-115	6.1	4.6	0.06	-	0.40	0.07	6	-	-	17.1	11.0	0.2	0.2	28.5
115-115	6.0	4.4	0.07	-	0.27	0.05	5	-	-	20.3	14.6	0.7	0.2	35.8

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 %
0-23	70	46.6	140	15.4	-	-	0
23-42	62	30.3	421	1.2	-	-	1
42-67	65	33.7	169	3.0	-	-	1
67-88	67	43.0	192	1.5	-	-	1
88-115	82	34.9	97	1.4	-	-	1
115-115	93	38.7	141	0.9	-	-	1

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
0-23	8.9	66	-	0.98	0.54	6.50	0.90	-	-	-	3.38
23-42	10.2	99	-	0.98	0.54	8.50	1.90	-	-	-	5.01
42-67	9.8	90	-	2.34	1.46	7.50	1.10	-	-	-	4.13
67-88	9.0	68	-	0.53	0.38	6.30	0.50	-	-	-	2.20
88-115	9.0	44	-	0.39	0.29	5.40	0.50	-	-	-	1.77
115-115	9.0	52	-	0.34	0.28	4.30	0.30	-	-	-	1.27

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
0-23	-	-	0.5	-	-	-	-	-	-
42-67	-	-	0.0	-	-	-	-	-	-
67-88	-	-	0.0	-	-	-	-	-	-
88-115	-	-	0.0	-	-	-	-	-	-
115-115	-	-	0.0	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-23	-	-	-	-	strong	-	-	-	-	-	weak to medium	-
23-42	-	-	-	-	medium to strong	-	-	-	-	-	-	-
42-67	-	-	-	-	strong	-	-	-	-	-	very weak to weak	-
67-88	-	-	-	-	strong	-	-	-	-	-	weak	-
88-115	-	-	-	-	medium to strong	-	-	-	-	-	weak to medium	-
115-115	-	-	-	-	strong	-	-	-	-	-	weak to medium	-

Profile description

Ah 0-23 cm	dark yellowish brown (10YR 4/4, dry)silty clay loam,moderate medium subangular blocky to moderate medium angular blocky,slightly hard,common fine continuous inped tubular random pores and common continuous inped tubular random pores moderately porous (40-60 vol%),very few fine gravel fresh "talpetate" fragments,abrupt smooth boundary to,
Bm 23-42 cm	strong brown (7.5YR 5/8, dry)broken platy strongly cemented duripan pans,abrupt smooth boundary to,
42-67 cm	dark yellowish brown (10YR 3/6, dry)loam,weak to moderate fine and medium subangular blocky,slightly hard,common very fine continuous inped tubular random pores moderately porous (40-60 vol%),very frequent medium gravel fresh "talpetate" fragments,clear broken boundary to,
C 67-88 cm	strong brown (7.5YR 4/6, dry)silt loam,clear broken boundary to,
2B 88-115 cm	(dark) brown (7.5YR 4/4, dry)silty clay loam,moderate medium subangular blocky,hard,common fine to coarse continuous inped tubular random pores moderately porous (40-60 vol%),very few fine gravel fresh pyroclastic fragments,clear wavy boundary to,
2C 115- cm	reddish brown (5YR 4/4, dry)silty clay loam,strong medium prismatic and strong medium angular blocky,hard,few fine continuous inped tubular random pores slightly porous (<40 vol%),few small spherical manganiferous concretions,few fine gravel weathered pyroclastic fragments,

Depth1	115cm
Kind 1 (parent material) ; Parker (eds), 1984	pyroclastic, consolidated
Mode of accumulation or deposition of parent material	ejecta ash
Soil Depth	23cm
Texture of parent material	loamy
Texture of parent material (second entry)	loamy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	partially or moderately

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	shrubland, grazed
Remarks on Land Use / Vegetation	LANDUSE: In past used for maize, beans, tomatoes
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)	modified
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	semi-deciduous shrub

Altitude	0m
Physiographic Unit	Pacific Coastal Plain
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.	piedmont
Slope	4%
Slope Aspect	west
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Lower limit of a slow permeable or stagnating layer in the profile	42cm
Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-115cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	medium
Drainage class - intergrade; FAO (2006) - Guidelines for soil description	well
Upper limit of a slow permeable or stagnating layer in the profile	23cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Average size of stone	1
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
Rock outcrop class (FAO (2006) - Guidelines for soil description)	little rocky
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Shape of stones (on average)	angular irregular
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none

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Reference soil Nicaragua 10: Andosol

Characteristics

Reference soil NI010: Andosols

Classification