Reference soil Nicaragua 02: Phaeozem

NI002

Phaeozems occur all over the world, but especially on the more moist side of the steppe regions, bordering Chernozems.

Characteristics

Soils having a mollic horizon (deep, brownish or blackish surface horizon with a significant accumulation of organic matter and high base saturation); a base saturation of 50 percent or more between 25 and 100 cm from the soil surface; a calcium carbonate-free soil matrix at least to a depth of 100 cm from the soil surface, or to a contrasting layer between 25 and 100 cm; no diagnostic horizons other than an albic, argic, cambic or vertic horizon, or a petrocalcic horizon in the substratum.

Distribution of Phaeozems (rough estimation supplied by soilgrids)

Reference soil NI002: Phaeozems

Formerly agricultural exploitation, mainly sorghum (verbal comm.). Now six years of secondary forest, dominant species: Lonchocarpus minimifloras (Chaperno), Acacia costaricensis (Cornizuelo), Stemnadenia spp. (Cachito). The B horizon has occasionally pockets of grey clay (10 YR 5/2). The CB horizon has pockets of light grey clay (10 YR 5/1). Short description: Moderately deep, well drained, very dark grey clay; roots penetrates easily the weathered rock C horizon, therefore effective soil depth > 80 cm

Classification

WRB 2006

WRB 1998

Vertic-Endoleptic- Phaeozem (Clayic)

Endoleptic- Phaeozem

0-40 cm	mollic horizon
-	vertic

0-40 cm	mollic horizon
5-50 cm	cambic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Verti-Haplic Phaeozem

Haplic Phaeozem

0-40 cm	mollic A horizon
5-50 cm	cambic B horizon
-	vertic

0-40 cm	mollic A horizon
5-50 cm	cambic B horizon

Local classification:	Chocolito

Other classification

USDA-SCS (1975)

Ustropept ustic clayey isohyperthermic

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
0-5	-	1.6	1.6	2.1	4.1	2.7	12.1	6.1	16.8	22.9	65.0
5-40	-	3.0	1.6	1.0	2.5	1.6	9.7	4.0	15.3	19.3	71.1
40-50	-	3.1	3.4	2.5	2.6	1.9	13.5	9.9	13.9	23.8	62.7
50-75	-	4.8	2.5	1.4	2.5	1.6	12.8	7.1	27.6	34.7	52.5
75-100	-	2.9	3.8	2.9	2.7	1.7	14	7.5	36.9	44.4	41.6

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-5	-	-	-	36.4	65.0
10-15	1.057	-	-	-	-
5-40	-	-	-	54.5	71.1
40-50	-	-	-	49.4	62.7
50-75	-	-	-	42.7	52.5
75-100	-	-	-	29.5	41.6

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
10-15	1.057	61.8	57.5	53.1	49.0	43.7	43.2	33.3	32.9

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
0-5	6.8	5.8	0.21	1.6	2.88	0.33	9	-	-	54.9	7.4	1.5	0.2	64.0
5-40	6.2	4.6	0.06	-	0.99	0.12	8	-	-	58.6	7.6	0.3	0.5	67.0
40-50	6.1	4.3	0.07	-	0.57	0.07	8	-	-	51.4	5.4	0.3	0.7	57.8
50-75	6.3	4.2	0.05	-	0.21	-	-	-	-	49.6	4.0	0.3	0.8	54.7
75-100	6.6	4.4	0.07	1.1	0.11	-	-	-	-	45.5	2.5	0.3	0.8	49.1

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 %
0-5	109	58.9	91	10.1	-	-	0
5-40	111	60.4	85	3.5	-	-	1
40-50	108	53.6	85	2.0	-	-	1
50-75	107	50.9	97	0.7	-	-	2
75-100	105	46.8	113	0.4	-	-	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
0-5	-	-	-	0.25	0.05	-	-	-	-	-	0.31
5-40	-	-	-	0.21	0.02	-	-	-	-	-	0.17
40-50	-	-	-	0.16	0.06	-	-	-	-	-	0.12
50-75	-	-	-	0.13	0.05	-	-	-	-	-	0.09
75-100	-	-	-	0.10	0.02	-	-	-	-	-	0.07

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-5	-	-	-	-	-	-	weak	-	-	weak	very strong	-
5-40	-	-	-	-	-	-	weak	-	-	weak	very strong	-
40-50	-	-	-	-	-	-	weak	-	-	weak	very strong	-
50-75	-	-	-	-	-	-	weak	-	-	weak	very strong	-
75-100	-	-	-	-	-	-	-	-	-	weak	very strong	-

Profile description

Ah 0-5 cm	(10YR 2.5/1, moist)clay,weak fine and medium subangular blocky,friable sticky plastic,common fine interstitial pores,few fine gravel weathered fragments,clear smooth boundary to,
B 5-40 cm	(10YR 2.5/no, moist)clay,strong coarse angular blocky,firm sticky plastic,common fine interstitial pores,few fine gravel weathered fragments,gradual smooth boundary to,
40-50 cm	dark grey (10YR 4/1, moist)clay,moderate coarse angular blocky,firm sticky plastic,common fine interstitial pores,frequent fine gravel weathered fragments,clear smooth boundary to,
CB 50-80 cm	(light) grey (10YR 6/1, moist)clay very gravelly,

Kind 1 (parent material) ; Parker (eds), 1984	interbedded sedimentary rock
Mode of accumulation or deposition of parent material	residual material
Soil Depth	80cm
Texture of parent material	clayey
Weathering Resistance	moderate

Land use or vegetation in the immediate vicinity of the site	non-agricultural land
Remarks on Land Use / Vegetation	VEGETATION: Dominant species Lonchocarpus minimifloras (Chaperno), Acacia costaricensis (Cornizuelo), Stemnadenia spp. (Cachito) LANDUSE: Formerly agricultural exploitation, mainly sorghum (verbal comm.), now six years of secondary forest
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	secondary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	semi-deciduous woodland

Altitude	0m
Physiographic Unit	valley, weakly undulating
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	low hill
Slope	4%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

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	moderate
Estimated run off (class)	medium
Drainage class - intergrade; FAO (2006) - Guidelines for soil description	moderately well

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Surface cracking	no cracks observed
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 02: Phaeozem

Characteristics

Reference soil NI002: Phaeozems

Classification