Reference soil South Africa 20: Umbrisol

ZA020

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 ZA020: Umbrisols

Umbrisol

Classification

WRB 2006

WRB 1998

Ferralic- Umbrisol (Humic Hyperdystric Clayic Chromic)

Humic- Umbrisol

0-37 cm	umbric horizon
-	ferralic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Ferrali-Humic Cambisol

Humic Cambisol

0-37 cm	umbric A horizon
-	ferralic

0-37 cm	umbric A horizon
-	ferralic

Local classification:	Hutton Form, Lillieburn Family

Other classification

USDA-NRCS (1999)	Humic Rhodic Hapludox
USDA-SCS (1975)	Humic Rhodic Haplumbrept udic fine 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
0-15	-	0.1	2.2	7.9	14.5	7.0	31.7	7.5	10.4	17.9	50.4
15-37	-	0.1	1.8	7.3	14.4	6.9	30.5	8.7	10.3	19	50.6
37-60	-	0.1	2.3	7.7	15.2	6.8	32.1	8.8	8.5	17.3	50.7
60-80	-	0.1	1.8	6.5	15.1	7.3	30.8	6.4	9.3	15.7	53.5
80-100	-	0.2	1.2	5.8	14.6	7.5	29.3	8.0	9.0	17	53.7
100-120	-	0.2	1.6	6.4	15.2	7.3	30.7	7.3	7.4	14.7	54.6
120-140	-	0.2	2.0	7.2	17.2	7.8	34.4	6.3	7.0	13.3	52.3

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-15	-	-	-	14.9	50.4
15-37	-	-	-	11.4	50.6
37-60	-	-	-	12.0	50.7
60-80	-	79	-	2.5	53.5
80-100	-	-	-	3.0	53.7
100-120	-	79	-	2.0	54.6
120-140	-	-	-	4.2	52.3

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
0-15	5.2	4.3	0.05	-	2.57	0.19	14	1.1	0.7	2.6	0.6	0.2	0.2	3.6
15-37	5.2	4.3	0.04	-	2.96	0.20	15	1.1	0.8	2.6	0.4	0.1	0.3	3.4
37-60	5.1	4.3	0.03	-	1.79	0.11	16	1.2	0.8	1.5	0.2	0.2	1.1	3
60-80	5.3	4.5	0.02	-	0.33	0.07	5	0.4	0.1	1.0	0.2	0.1	0.2	1.5
80-100	5.3	4.7	0.01	-	0.31	0.04	8	0.2	0.0	1.0	0.2	0.1	0.2	1.5
100-120	5.2	4.5	0.01	-	0.33	0.04	8	0.3	0.0	1.0	0.2	0.1	0.2	1.5
120-140	4.9	4.4	0.02	-	0.20	0.02	10	0.5	0.4	1.0	0.2	0.0	0.2	1.4

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	14	25.4	50	9.0	-	3	1
15-37	13	25.8	51	10.4	-	3	1
37-60	14	20.9	41	6.3	-	4	5
60-80	11	13.8	26	1.2	-	1	1
80-100	12	12.9	24	1.1	-	0	2
100-120	13	11.6	21	1.2	-	0	2
120-140	11	12.5	24	0.7	-	2	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	-	-	-	0.48	0.02	3.93	1.00	-	-	-	0.43
15-37	-	-	-	0.47	0.02	3.74	0.93	-	-	-	0.40
37-60	-	-	-	0.44	0.02	4.18	1.00	-	-	-	0.35
60-80	-	-	-	0.33	0.02	4.37	0.66	-	-	-	0.42
80-100	-	-	-	0.23	0.04	4.63	0.51	-	-	-	0.58
100-120	-	-	-	0.22	0.04	4.71	0.54	-	-	-	0.58
120-140	-	-	-	0.18	0.03	4.55	0.42	-	-	-	0.53

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
0-15	26.2	39.1	16.6	0.03	0.52	0.46	-	1.29
15-37	25.7	38.3	16.5	0.04	0.52	0.49	-	1.26
37-60	29.0	39.2	16.9	0.02	0.48	0.42	-	1.30
60-80	23.0	39.3	17.0	0.00	0.43	0.41	-	1.30
80-100	23.9	39.1	16.6	0.01	0.40	0.40	-	1.32
100-120	24.8	38.6	17.0	0.01	0.38	0.43	-	1.28
120-140	25.0	39.4	17.2	0.01	0.41	0.56	-	1.27

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
0-15	0.05	0.32	17.4	102	1.1	4.2	0.9	3.7
15-37	0.05	0.33	17.2	100.3	1.1	4.2	0.9	3.6
37-60	0.04	0.22	18.4	105.98	1.3	4.6	1	3.6
60-80	0.04	0.23	18.5	100.21	1	3.6	0.8	3.6
80-100	0.04	0.22	17.8	99.79	1	3.8	0.8	3.7
100-120	0.05	0.20	17.5	100.25	1.1	3.9	0.9	3.6
120-140	0.05	0.17	16.6	100.67	1.1	3.9	0.8	3.6

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
0-15	18.1	0.09	8.1	0.28	0.28	-	56.4	1.21
15-37	17.1	0.08	7.8	0.26	0.26	-	57.7	1.15
37-60	18.5	0.02	8.4	0.25	0.25	-	57.4	1.24
60-80	20.0	0.01	9.1	0.26	0.22	-	56.4	1.34
80-100	20.7	0.00	9.5	0.25	0.21	-	56.7	1.40
100-120	21.0	0.00	9.6	0.28	0.2	-	56.3	1.40
120-140	20.2	0.03	9.3	0.33	0.19	-	59.3	1.37

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
0-15	3.5	17.0	0.04	0.10	5.3	18.5	4.1
15-37	3.4	15.9	0.03	0.10	5.7	19.7	4.4
37-60	3.5	14.0	0.03	0.07	5.3	18.2	4.1
60-80	3.4	12.7	0.04	0.06	4.8	16.5	3.7
80-100	3.4	11.9	0.04	0.06	4.6	15.9	3.6
100-120	3.4	11.8	0.04	0.06	4.5	15.6	3.5
120-140	3.4	10.8	0.05	0.07	5	17.0	3.9

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium
15-37	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium
37-60	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium
60-80	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium
80-100	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium
100-120	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium
120-140	-	-	-	-	-	-	weak to medium	-	-	-	-	weak to medium

Sand mineralogy

Depth (cm)	Heavy Frac. sand % w/w	K-Feldspar % w/w	Light Fra. sand % w/w	Opaque % w/w	Plagioclase % w/w	Quartz % w/w
100-120	0.6	-	99.4	70	-	100

Minerals

Depth (cm)	Anatase % w/w	Andalusite % w/w	Apatite % w/w	Augite % w/w	Biotite % w/w	Hornblende (basaltic) % w/w
100-120	2	-	-	-	-	-

Depth (cm)	Brookite % w/w	Chloritic % w/w	Disthene % w/w	Epidote % w/w	Garnet % w/w	Glaucophane % w/w
100-120	-	-	-	3	-	-

Depth (cm)	Grenate % w/w	Grossular % w/w	Muscovite % w/w	Rutile % w/w	Sillimanite % w/w	Spinel % w/w
100-120	-	-	-	24	-	-

Profile description

Ah1 0-15 cm	(7.5YR 2/3, dry) (5YR 2/2.5, moist)sandy clay,fine and medium subangular blocky,slightly hard very friable slightly sticky slightly plastic,many very fine and fine pores,many fine and medium roots,non calcareous,clear smooth boundary to,
Ah2 15-37 cm	(7.5YR 2/3, dry) (5YR 2/2.5, moist)sandy clay,fine and medium subangular blocky,slightly hard very friable slightly sticky slightly plastic,many very fine and fine pores,many fine and medium roots,non calcareous,clear smooth boundary to,
Bo1 37-60 cm	(5YR 3/6, dry) dark reddish brown (2.5YR 3/4, moist)sandy clay,porous massive,hard very friable slightly sticky slightly plastic,many very fine and fine pores,common fine and medium roots,non calcareous,gradual smooth boundary to,
Bo2 60-80 cm	red (2.5YR 4/8, dry) (10R 3/7, moist)sandy clay,porous massive,slightly hard very friable slightly sticky slightly plastic,many very fine and fine pores,common fine and few medium roots,non calcareous,diffuse smooth boundary to,
Bo3 80-120 cm	red (2.5YR 4/8, dry) (10R 3/7, moist)sandy clay,porous massive,slightly hard very friable slightly sticky slightly plastic,many very fine and fine pores,few roots,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	dolerite
Kind 2 (parent material) (second entry); Parker (eds), 1984	sandstone
Mode of accumulation or deposition of parent material	colluvial
Mode of accumulation or deposition of parent material (second entry)	colluvial
Remarks on Parent Materials	Colluvial mixture of strongly weathered dolerite and probably some micaceous sandstone of the middle Ecca
Texture of parent material	sandy clay
Texture of parent material (second entry)	sandy clay
Weathering Resistance	poor
Weathering Resistance (second entry)	moderate
General characterization of the status of weathering of solid rock	highly
General characterization of the status of weathering of solid rock (second entry)	highly

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	short grassland

Altitude	1250m
Physiographic Unit	slope
Physiographic position of the site	upper slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	valley
Slope	33%
Slope Aspect	north-west
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-30cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	30-120cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil South Africa 20: Umbrisol

Characteristics

Reference soil ZA020: Umbrisols

Classification