Reference soil Nicaragua 07: Andosol

NI007

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 NI007: Andosols

Moderately deep, (moderately) well drained, very dark brown to brown silty clay loam to silty loam soil developed from volcanic ejecta, derived from tuff. The soil contains fresh pyroclastic and talpetate fragments, is moderately structured and permeable and highly porous. The profile consists of three different horizon sequences separated by two thin cemented layers, in Nicaragua called "talpetate" (Bm horizon). In this part of Nicaragua the talpetate is probably of geogenetic origin (Bm horizon becomes C horizon). Due to the high erosion hazard, the area urgently needs some soil conservation measures, because otherwise the talpetate layer will outcrop at the surface and the soil will loose its agricultural potential. The profile forms part of the NIC05 to NIC09 toposequence.

Classification

WRB 2006

WRB 1998

Duric-Endoleptic-Vitric- Andosol (Hypereutric)

Endolepti-Petroduric- Andosol (Hypereutric)

15-43 cm	cambic horizon
43-46 cm	petroduric horizon
-	continuous rock
-	vitric

0-15 cm	ochric horizon
0-43 cm	vitric horizon
43-46 cm	petroduric horizon
57-60 cm	petroduric horizon
-	continuous hard rock

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Duri-Vitric Andosol duripan

Vitric Andosol duripan

0-15 cm	ochric A horizon
15-43 cm	cambic B horizon
- cm	mollic A horizon
-	andic
-	continuous hard rock

0-15 cm	ochric A horizon
15-43 cm	cambic B horizon
- cm	duripan horizon
- cm	mollic A horizon
-	exchange complex dominated by amorphous material

Local classification:	Zambrano Series

Other classification

USDA-NRCS (1999)	Entic Durustoll
USDA-SCS (1975)	Entic Durustoll ustic fine-silty mixed 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
0-15	-	1.6	2.4	1.8	2.9	2.0	10.7	9.0	40.1	49.1	40.1
15-43	-	4.5	5.3	4.2	5.7	4.3	24	10.0	39.3	49.3	26.7
46-57	-	3.5	4.7	4.0	6.5	4.2	22.9	16.4	44.6	61.0	16.1
60-66	-	4.7	6.8	5.5	9.8	7.3	34.1	18.1	35.6	53.7	12.3
66-66	-	5.3	6.5	5.1	7.1	8.0	32	21.3	37.8	59.1	8.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-15	1.005	-	-	20.4	40.1
15-43	0.801	-	-	7.5	26.7
46-57	0.825	-	-	10.2	16.1
60-66	-	-	-	7.5	12.3
66-66	-	-	-	7.3	8.8

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
0-15	1.005	59.1	58.6	58.0	50.4	46.5	43.5	37.8	36.1
15-43	0.801	66.3	64.6	63.0	56.7	51.7	47.8	36.9	33.3
46-57	0.825	65.9	64.0	61.7	55.0	50.3	46.0	35.1	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
0-15	7.1	5.5	0.06	2.2	2.21	0.23	10	-	-	38.0	15.8	2.3	0.1	56.2
15-43	7.6	5.8	0.06	2.4	1.22	0.12	10	-	-	38.9	15.5	0.6	0.3	55.3
46-57	7.7	5.7	0.07	2.6	0.70	0.09	8	-	-	36.7	22.7	0.9	0.4	60.7
60-66	7.8	5.7	0.05	2.7	0.42	0.06	7	-	-	36.6	18.8	0.6	0.5	56.5
66-66	7.9	5.7	0.04	2.6	0.19	0.03	6	-	-	31.8	14.5	0.3	0.7	47.3

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 %
0-15	105	53.3	133	7.7	-	-	0
15-43	95	58.1	218	4.3	-	-	1
46-57	95	64.2	399	2.5	-	-	1
60-66	94	60.2	489	1.5	-	-	1
66-66	110	42.9	488	0.7	-	-	2

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
0-15	8.8	54	-	0.69	0.39	-	-	-	-	-	1.69
15-43	9.3	60	-	0.80	0.41	-	-	-	-	-	1.80
46-57	9.3	56	-	0.78	0.36	-	-	-	-	-	2.11
60-66	9.2	47	-	0.61	0.33	-	-	-	-	-	1.63
66-66	9.0	33	-	0.53	0.29	-	-	-	-	-	1.17

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
0-15	-	-	8.2	-	-	-	-	-	-
15-43	-	-	2.2	-	-	-	-	-	-
46-57	-	-	2.0	-	-	-	-	-	-
60-66	-	-	1.4	-	-	-	-	-	-
66-66	-	-	0.0	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	-	-	medium to strong	-	-	-	-	-	-	-
15-43	-	-	-	-	medium to strong	-	-	-	-	-	-	-
46-57	-	-	-	-	weak	-	-	-	-	-	medium to strong	-
60-66	-	-	-	-	weak	-	-	-	-	-	strong	-
66-66	-	-	-	-	-	-	-	-	-	-	strong	-

Profile description

Ap 0-15 cm	very dark brown (10YR 2/2, moist) dark greyish brown (10YR 4/2, dry)silty clay loam slightly gravelly,moderate medium subangular blocky to moderate medium wedge-shaped angular blocky,hard,few very fine pores highly porous (>60 vol%),few fine gravel fresh pyroclastic very few medium gravel fresh talpetate fragments,abrupt smooth boundary to,
B 15-43 cm	(dark) brown (10YR 4/3, moist) yellowish brown (10YR 5/6, dry)loam slightly gravelly,weak to moderate medium subangular blocky to weak to moderate medium wedge-shaped angular blocky,slightly hard,many medium pores and few pores highly porous (>60 vol%),very few medium gravel fresh talpetate fragments,abrupt smooth boundary to,
2Bb 46-57 cm	dark yellowish brown (10YR 3/4, moist) dark yellowish brown (10YR 4/4, dry)light olive brown (2.5Y 5/4, moist) yellow (2.5Y 7/6, dry),silt loam gravelly,weak medium subangular blocky,slightly hard,many medium pores highly porous (>60 vol%),frequent fine gravel fresh pyroclastic frequent fine gravel fresh talpetate fragments,broken platy strongly cemented duripan pans,abrupt smooth boundary to,abrupt smooth boundary to,
3Bb 60-66 cm	dark brown (10YR 3/3, moist) brown (10YR 5/3, dry)silt loam,weak medium subangular blocky,slightly hard,many medium pores highly porous (>60 vol%),frequent fine gravel fresh pyroclastic frequent fine gravel fresh talpetate fragments,abrupt smooth boundary to,
2Bm 57-60 cm	light olive brown (2.5Y 5/4, moist) yellow (2.5Y 7/6, dry) broken platy strongly cemented duripan pans,abrupt smooth boundary to,

Depth1	46cm
Kind 1 (parent material) ; Parker (eds), 1984	tuff
Kind 2 (parent material) (second entry); Parker (eds), 1984	tuff
Mode of accumulation or deposition of parent material	ejecta ash
Mode of accumulation or deposition of parent material (second entry)	ejecta ash
Soil Depth	66cm
Texture of parent material	loamy
Texture of parent material (second entry)	silty
Weathering Resistance	moderate
Weathering Resistance (second entry)	poor
General characterization of the status of weathering of solid rock	partially or moderately
General characterization of the status of weathering of solid rock (second entry)	slightly

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Intensity of the soil erosion type	slight
Soil erosion type	rill
Slope stability	stable

Major crops	sorghum
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	medium level arable farming
Remarks on Land Use / Vegetation	VEGETATION: Actual landuse treatened by erosion
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	continuous crop rotation

Altitude	130m
Physiographic Unit	Pacific Volcanic Province
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	2%
Slope Aspect	west-north-west
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Lower limit of a slow permeable or stagnating layer in the profile	0cm
Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	43-66cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-43cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium
Upper limit of a slow permeable or stagnating layer in the profile	66cm

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
Microrelief Height: variation in height	10
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	ripples
Microrelief pattern	linear
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Shape of stones (on average)	angular blocky
Surface stoniness class (FAO (2006) - Guidelines for soil description)	fairly stony

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Reference soil Nicaragua 07: Andosol

Characteristics

Reference soil NI007: Andosols

Classification