Reference soil South Africa 03: Umbrisol

ZA003

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 ZA003: Umbrisols

LAND USE AND VEGETATION: Forest was planted 20 years ago. Human influence: superficial soil management. ADDITIONAL NOTES ON PROFILE DESCRIPTION: R - Pinkish grey mudstone, continuous.

Classification

WRB 2006

Cambic-Ferralic- Umbrisol (Humic Hyperdystric Chromic)

0-40 cm	umbric horizon
40-82 cm	cambic horizon
-	ferralic

0-40 cm	umbric horizon
40-82 cm	cambic horizon
-	ferralic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Ferrali-Humic Cambisol

Humic Cambisol

0-40 cm	umbric A horizon
40-82 cm	cambic B horizon

0-40 cm	umbric A horizon
40-82 cm	cambic B horizon
-	ferralic

Local classification:	Clovelly Form

Other classification

USDA-SCS (1975)

Haplumbrept

More images

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	-	1.9	7.9	12.9	26.1	7.5	56.3	4.0	7.3	11.3	32.4
15-30	-	1.9	7.7	11.4	25.8	8.1	54.9	0.8	7.2	8	37.1
30-45	-	2.3	7.6	9.9	24.5	7.9	52.2	1.4	7.4	8.8	39.0
45-66	-	4.5	7.9	10.4	22.9	8.4	54.1	1.4	7.6	9	36.9

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	-	-	-	-	32.4
15-30	-	-	-	-	37.1
30-45	-	-	-	-	39.0
45-66	-	-	-	-	36.9

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
0-15	4.4	3.9	0.06	-	3.29	0.14	23	5.5	4.7	0.4	0.2	0.3	0.3	1.2
15-30	4.8	4.1	0.03	-	2.17	0.09	24	4.1	3.8	0.4	0.2	0.3	0.3	1.2
30-45	4.7	4.1	0.02	-	1.09	0.06	18	3.3	2.9	0.4	0.2	0.2	0.2	1
45-66	4.7	4.1	0.03	-	0.62	0.03	21	3.1	2.7	0.4	0.2	0.1	0.2	0.9

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	6	18.9	58	11.5	-	-	2
15-30	8	15.4	42	7.6	-	-	2
30-45	9	11.5	29	3.8	-	-	2
45-66	9	9.6	26	2.2	-	-	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	-	-	-	-	-	2.3	-	-	-	-	-
15-30	-	-	-	-	-	2.3	-	-	-	-	-
30-45	-	-	-	-	-	2.4	-	-	-	-	-
45-66	-	-	-	-	-	2.5	-	-	-	-	-

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	38.6	32.3	12.1	0.00	1.11	2.85	-	0.90
15-30	39.3	31.7	12.1	0.01	1.13	3.00	-	1.00
30-45	38.6	32.2	12.5	0.01	1.13	3.31	-	0.90
45-66	39.6	32.6	12.7	0.00	1.13	3.69	-	0.92
66-66	47.2	30.2	8.2	0.02	1.33	5.85	-	0.61

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	0.03	0.33	11.7	99.92	2	8.5	1.6	4.2
15-30	0.03	0.28	11.6	100.15	2.1	8.6	1.7	4.1
30-45	0.03	0.29	11.3	100.27	2	8.2	1.6	4
45-66	0.04	0.28	11.0	101.96	2.1	8.3	1.7	4
66-66	0.10	0.32	7.8	101.63	2.7	15.3	2.3	5.8

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
0-15	11.3	0.00	4.5	1.06	0.35	-	73.3	0.79
15-30	11.6	0.00	4.6	1.12	0.36	-	73.6	0.81
30-45	11.5	0.00	4.7	1.26	0.38	-	74.3	0.82
45-66	11.3	0.00	4.6	1.44	0.36	-	76.9	0.78
66-66	19.8	0.00	8.0	4.58	1.04	-	61.7	0.94

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	3.9	9.3	0.01	0.05	11	43.3	8.8
15-30	3.9	7.3	0.01	0.04	10.8	42.5	8.6
30-45	3.8	5.7	0.01	0.04	11	42	8.7
45-66	3.8	4.5	0.01	0.04	11.5	44.4	9.2
66-66	3.9	4.4	0.12	0.05	5.3	20.5	4.2

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-15	-	-	-	weak to medium	-	-	strong	very weak to weak	strong	-	-	weak to medium
15-30	-	-	-	weak to medium	-	-	strong	very weak to weak	strong	very weak to weak	-	weak to medium
30-45	-	-	-	weak to medium	-	-	strong	very weak to weak	strong	-	-	weak to medium
45-66	-	-	-	weak to medium	-	-	strong	weak to medium	strong	-	-	very weak to weak

Profile description

Ah1 0-20 cm	(10YR 3.5/2, dry) black (10YR 2/1, moist)sandy clay loam,weak fine subangular blocky and granular,slightly hard very friable slightly sticky slightly plastic,many medium pores and many fine pores,few fine and medium and few coarse roots,non calcareous,gradual smooth boundary to,
Ah2 20-40 cm	(10YR 3.5/2.5, dry) very dark brown (10YR 2/2, moist)sandy clay,very weak fine and medium subangular blocky,slightly hard friable slightly sticky slightly plastic,common very fine pores,few medium and coarse roots,non calcareous,gradual smooth boundary to,
Bw1 40-55 cm	strong brown (7.5YR 4/6, dry) (7.5YR 3/6, moist)sandy clay,very weak blocky,slightly hard friable slightly sticky slightly plastic,common very fine pores,few medium and coarse roots,non calcareous,gradual smooth boundary to,
Bw2 55-82 cm	undescribed colour (5YR 4/8, moist) reddish yellow (7.5YR 6/6, dry)sandy clay,very weak blocky,slightly hard friable slightly sticky slightly plastic,common very fine pores,few medium and coarse roots,non calcareous,abrupt smooth boundary to,
R 82-82 cm	rock structurehard,dominant weathered mudstone,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	shale/siltstone
Mode of accumulation or deposition of parent material	colluvial
Remarks on Parent Materials	Ecca shales
Texture of parent material	sandy clay
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	partially or moderately

Land use or vegetation in the immediate vicinity of the site	afforestation
Remarks on Land Use / Vegetation	Cultivated Eucalyptus grandis forest
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	closed forest

Altitude	1067m
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.	low hill
Slope	5%
Slope Aspect	north-west
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-90cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow

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
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	level
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

You are here

Reference soil South Africa 03: Umbrisol

Characteristics

Reference soil ZA003: Umbrisols

Classification