Reference soil South Africa 07: Umbrisol

ZA007

Umbrisols occur mainly in regions where precipitation exceeds considerably the evapotranspiration. They are dominantly associated with acid parent materials.

Characteristics

Soils having an umbric horizon (deep, brownish or blackish surface horizon with a significant accumulation of organic matter and low base saturation). They have no diagnostic horizons other than an anthropedogenic horizon less than 50 cm thick, or an albic or cambic horizon.

Distribution of Umbrisols (rough estimation supplied by soilgrids)

Reference soil ZA007: Umbrisols

Umbrisol. Regular burning of the grass

Classification

WRB 2006

WRB 1998

Epileptic- Umbrisol (Humic)

Epileptic- Umbrisol

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Umbri-Humic Cambisol

Humic Cambisol

0-30 cm

umbric A horizon

0-30 cm

umbric A horizon

Local classification:	Glenrosa Form, Tsende Family

Other classification

USDA-NRCS (1999)	Humic Lithic Dystrudept
USDA-SCS (1975)	Humic Lithic Haplumbrept udic fine-loamy kaolinitic 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	44	15.5	9.7	19.2	26.3	5.5	76.2	4.4	5.1	9.5	14.3
10-20	51	20.8	8.9	14.2	18.9	4.7	67.5	5.9	5.3	11.2	21.3
25-60	-	8.9	15.6	11.4	12.1	4.9	52.9	9.0	10.1	19.1	30.0

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	-	-	-	-	14.3
10-20	-	-	-	-	21.3
25-60	-	-	-	-	30.0

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	5.5	4.4	0.08	-	1.76	0.06	29	-	-	1.2	1.0	0.5	0.3	3
10-20	5.3	4.2	0.06	-	1.51	0.05	30	-	-	0.6	0.9	0.3	0.2	2
25-60	5.5	4.3	0.03	-	0.66	0.02	33	-	-	0.4	1.6	0.2	0.3	2.5

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	35	8.5	59	6.2	-	-	4
10-20	21	9.4	44	5.3	-	-	2
25-60	26	9.8	33	2.3	-	-	3

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	-	-	-	-	-	0.8	0.1	-	-	-	-
10-20	-	-	-	-	-	1.1	0.2	-	-	-	-
25-60	-	-	-	-	-	2.2	0.3	-	-	-	-

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	43.4	30.4	10.4	0.02	0.56	1.86	-	1.25
10-20	42.1	31.7	10.3	0.01	0.55	1.77	-	1.16
25-60	40.5	34.3	11.2	0.00	0.45	1.25	-	0.92

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	0.09	0.25	11.6	99.7	2.4	11.1	2	4.6
10-20	0.04	0.17	11.7	99.6	2.3	10.8	1.9	4.8
25-60	0.04	0.10	12.8	101.56	2	9.6	1.7	4.8

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	7.8	0.04	2.2	2.70	0.10	-	83.5	0.37
10-20	10.1	0.02	2.7	2.85	0.11	-	79.2	0.43
25-60	20.6	0.00	5.6	4.78	0.25	-	61.0	0.53

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	5.6	4.6	0.02	0.03	18.2	100.9	15.4
10-20	5.9	5.1	0.01	0.02	13.3	78.1	11.4
25-60	5.8	7.3	0.03	0.03	5	28.9	4.3

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	-	-	very strong	weak to medium	-	very weak to weak	-	-
10-20	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	-	very weak to weak	-	-
25-60	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	-	very weak to weak	-	-

Profile description

Ah 0-30 cm	(7.5YR 4/2.5, dry) (7.5YR 2.5/2.5, moist)gravelly loamy sand,single grain,soft (dry) loose (moist) non sticky non plastic,highly porous (>60 vol%),common very fine and fine roots,few fine and medium gravel fresh sandstone,non calcareous,abrupt irregular boundary to,
R 30-100 cm	yellowish red (5YR 4/6, dry)strongly coherent rock structure,extremely hard,many coarse prominent clear mottles (5YR 3/4) and (5YR 6/6),slightly porous (<40 vol%),common very fine and fine roots,dominant fresh granite fragments,non calcareous,

Depth1	30cm
Kind 1 (parent material) ; Parker (eds), 1984	granite
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	granite of Basement Complex
Soil Depth	30cm
Texture of parent material	loamy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	slightly

Land use or vegetation in the immediate vicinity of the site	extensive grazing
Remarks on Land Use / Vegetation	VEGETATION: some Acacia trees
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	765m
Physiographic Unit	slope
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.	hill
Slope	45%
Slope Aspect	east
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	hilly

Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
Dry From - To	0-30cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	30-100cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	rapid

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
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 South Africa 07: Umbrisol

Characteristics

Reference soil ZA007: Umbrisols

Classification