Reference soil Namibia 02: Calcisol

NA002

Calcisols occur in regions with distinct dry seasons, as well as in dry areas where carbonate-rich groundwater comes near the surface.

Characteristics

Soils having a (petro-)calcic horizon (horizon with accumulation of secondary calcium carbonates). In addition, they have no diagnostic horizons other than an ochric or cambic horizon, a calcareous argic horizon, or a gypsic horizon beneath a petrocalcic horizon.

Distribution of Calcisols (rough estimation supplied by soilgrids)

Reference soil NA002: Calcisols

BRIEF CHARACTERIZATION OF THE SOIL: A dark reddish brown non-calcareous sandy loam profile with a 10 cm thick, stony layer at 50 cm. Argillic horizon below 20 cm. Strongly weathered amphibolite, impregnated with calcium carbonate below 85 cm. ADDITIONAL NOTES ON PROFILE DESCRIPTION: B - cutans: dark reddish brown. 2B - texture: clayey, stones. Consistence, stickiness and plasticity refers to clay matrix. - stones: consisting of quartz and metamorphic rocks. 3C - also common fine distinct sharp white (10YR8/2) carbonatic pseudo mycelium. 3Cca - streaks with pinkish white (7.5YR8/3-8/1) and dark reddish brown (5YR3/8) as dominant colours, also many intermediate colours. - rock fragments: embedded in massive fine powdery lime, occuring in some parts of horizon. CLIMATE: xa - minimum precipitation.

Classification

WRB 2006

WRB 1998

Luvic- Calcisol (Aridic Hyperochric Chromic)

Aridi-Luvic- Calcisol (Hyperochric)

10-50 cm	argic horizon
50-70 cm	calcic horizon
-	calcaric

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Luvic Calcisol

Luvic Yermosol

0-10 cm	ochric A horizon
10-50 cm	argic B horizon
50-70 cm	calcic horizon
-	calcareous

0-10 cm	ochric A horizon
10-50 cm	argillic B horizon
50-70 cm	calcic horizon

Local classification:	Red brown soil of dry savanna

Other classification

USDA-SCS (1975)

Haplargid coarse-loamy over fragmental mixed thermic

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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	3	3.8	11.9	19.8	33.5	10.8	79.8	6.7	4.2	10.9	9.3
10-30	4	3.3	10.6	18.3	32.0	12.5	76.7	6.5	3.5	10	13.3
30-50	5	4.0	11.3	18.4	30.6	11.9	76.2	6.4	4.1	10.5	13.3

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	-	-	-	-	9.3
10-30	-	-	-	-	13.3
30-50	-	-	-	-	13.3

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	7.5	6.4	0.08	1.8	0.46	0.04	12	-	-	4.3	1.0	0.5	0.0	5.8
10-30	7.8	6.4	0.10	2.6	0.35	0.03	12	-	-	7.3	1.2	0.5	0.0	9
30-50	8.2	7.2	0.17	2.0	0.35	0.03	12	-	-	7.3	1.3	0.6	0.0	9.2

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	102	5.7	61	1.6	-	-	0
10-30	105	8.6	65	1.2	-	-	0
30-50	108	8.5	64	1.2	-	-	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	-	-	-	-	-	0.59	-	-	-	-	-
10-30	-	-	-	-	-	0.71	-	-	-	-	-
30-50	-	-	-	-	-	0.74	-	-	-	-	-

Elemental composition of the clay

Depth (cm)	SiO2 % w/w	Al2O3 % w/w	Fe2O3 % w/w	CaO % w/w	MgO % w/w	K2O % w/w	Na2O % w/w	TiO2 % w/w
0-10	47.1	20.3	16.2	0.28	3.64	3.27	-	1.18
10-30	47.8	20.2	16.1	0.18	3.67	0.07	-	1.10
30-50	47.6	19.7	15.8	0.21	3.69	2.94	-	1.07

Depth (cm)	MnO2 % w/w	P2O5 % w/w	Ign.Loss clay % w/w	Total Clay % w/w	SiO2/Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol	Al2O3/Fe2O3 mol/mol
0-10	0.17	0.42	8.5	101.06	3.9	7.7	2.6	2
10-30	0.14	0.24	8.7	98.2	4	7.9	2.7	2
30-50	0.14	0.23	9.5	100.88	4.1	8	2.7	2

Elemental composition of the soil

Depth (cm)	Al2O3 % w/w	CaO % w/w	Fe2O3 % w/w	K2O % w/w	MgO % w/w	Na2O % w/w	SiO2 % w/w	TiO2 % w/w
0-10	8.5	0.52	4.3	1.70	0.99	-	81.9	0.89
10-30	8.6	0.64	4.9	1.69	1.17	-	79.2	0.96
30-50	9.2	1.70	5.0	1.96	1.23	-	77.9	0.99
50-60	7.7	21.28	4.9	0.93	3.07	-	42.8	0.59
60-110	9.5	3.85	5.2	1.99	1.61	-	73.5	0.79

Depth (cm)	Al2O3/Fe2O3 mol/mol	LOI % w/w	MnO2 % w/w	P2O5 % w/w	SiO2 / Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol
0-10	3.1	1.8	0.07	0.02	16.3	50.6	12.4
10-30	2.7	2.1	0.07	0.01	15.6	43	11.5
30-50	2.9	2.1	0.07	0.01	14.4	41.4	10.7
50-60	2.5	17.4	0.07	0.05	9.4	23.2	6.7
60-110	2.9	3.1	0.08	0.01	13.1	37.6	9.7

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-10	-	-	-	very weak to weak	-	-	weak to medium	strong	-	-	strong	-
10-30	-	-	-	very weak to weak	-	-	weak to medium	strong	-	-	strong	-
30-50	-	-	-	very weak to weak	-	-	weak to medium	strong	-	-	strong	-

Profile description

Ah 0-10 cm	yellowish red (5YR 4/6, dry)sandy loam,massive,slightly hard friable non sticky non plastic,few very fine and fine roots,non calcareous,clear smooth boundary to,
Bt 10-50 cm	dark reddish brown (5YR 3/4, dry)sandy loam,weak medium subangular blocky,soft very friable non sticky non plastic,clay cutans around sand grains,few very fine roots,non calcareous,abrupt wavy boundary to,
2Bk 50-60 cm	dark reddish brown (5YR 3/4, dry)(5YR 3/6, dry),gravelly clay,moderate fine subangular blocky,moderate medium crumb,soft very friable slightly sticky slightly plastic,hard friable slightly sticky slightly plastic,common (5-15%) fine distinct sharp mottles 10YR7/3 (very pale brown) and few (2-5%) fine faint clear 7.5YR3/4 (dark brown) mottles,common powdery threadlike calcareous soft segregations,abundant rounded stones,moderately calcareous (2-10%),moderately calcareous (2-10%),clear irregular boundary to,abrupt wavy boundary to,
3Ck 85-110 cm	Invalid Code: (7.5YR 8/3, dry) and (7.5YR 8/1,dry)sandy clay loam,moderate fine subangular blocky and massive,friable,heterogeneous mottles,frequent small irregular hard calcareous concretions and frequent powdery irregular calcareous soft segregations,common weathered amphibolite fragments,strongly calcareous (10-25%),

Kind 1 (parent material) ; Parker (eds), 1984	highly weathered material
Mode of accumulation or deposition of parent material	unconsolidated, unspecified
Remarks on Parent Materials	Amphibolite of Archean age, overlain by a thin layer of clayey gravel by eolian-fluviatile loamy sand
Texture of parent material	loamy
General characterization of the status of weathering of solid rock	highly
General characterization of the status of weathering of solid rock (second entry)	highly

Intensity of the soil erosion type	slight
Intensity of the soil erosion type (second entry)	slight
Soil erosion type	wind
Soil erosion type (second entry)	sheet

Land use or vegetation in the immediate vicinity of the site	extensive grazing
Remarks on Land Use / Vegetation	VEGETATION: Savannah, with bushes and small trees. mainly Acacia spp. Highland Savannah after Giess(1971) LAND USE: Extensive grazing by cattle and sheep. Surface of soil is somewhat affected by grazing cattle and sheep
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	short grassland

Altitude	1800m
Physiographic position of the site	flat
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plateau
Slope	1%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Dry From - To	0-65cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	65-120cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow

Evidence of alkali ; Soil Survey Manual USDA, 1951	slightly alkaline
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 Namibia 02: Calcisol

Characteristics

Reference soil NA002: Calcisols

Classification