Reference soil Zambia 07: Regosol

ZM007

Regosols are found in areas where soil has been eroded to the extent that the underlying unconsolidated materials come near to the surface, or where soil formation has not played an important role, e.g. in desert regions. The name comes from the greek 'rhegos' :blanket meaning young soils on weathering materials.

Characteristics

Soils in medium and fine textured materials, having no distinctive horizons other than an ochric horizon at the surface.

Distribution of Regosols (rough estimation supplied by soilgrids)

Reference soil ZM007: Regosols

Regosol REFERENCE: prof. no. M-58. Soil Survey Unit, Mt Makulu, Chilanga

Classification

WRB 2006

Haplic- Regosol (Dystric Arenic)

63-160 cm

argic horizon

63-160 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Abrupti-Dystric Regosol

Dystric Regosol

0-30 cm	ochric A horizon
63-160 cm	argic B horizon
-	abrupt textural change
-	ferralic

0-30 cm	ochric A horizon
63-160 cm	argillic B horizon

Local classification:	Milima sand

Other classification

USDA-NRCS (1999)	Ustifluvent
USDA-SCS (1975)	Ustifluvent ustic sandy over loamy mixed 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
0-16	-	0.4	2.1	9.5	50.3	20.3	82.6	5.2	2.8	8	9.3
16-30	-	0.3	2.0	10.0	52.0	18.7	83	5.5	1.5	7	10.0
30-50	-	0.2	2.1	9.6	48.9	19.1	79.9	5.5	1.0	6.5	13.6
50-63	-	0.3	2.2	9.7	50.8	20.8	83.8	5.1	2.3	7.4	8.8
63-94	-	0.4	3.1	9.9	37.0	13.2	63.6	5.1	2.0	7.1	29.3
94-120	-	0.5	2.7	9.5	33.4	11.8	57.9	4.6	0.8	5.4	36.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-16	-	15	-	2.5	9.3
38-43	1.497	-	-	-	-
90-95	1.507	-	-	-	-
16-30	-	12	-	1.5	10.0
30-50	-	16	-	2.0	13.6
50-63	-	10	-	2.0	8.8
63-94	-	37	-	0.5	29.3
94-120	-	44	-	1.0	36.7

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
38-43	1.497	39.1	38.8	26.8	11.9	9.4	8.1	8.0	7.2
90-95	1.507	38.3	37.8	32.1	26.6	24.2	21.6	17.5	16.9

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
0-16	5.5	4.3	0.11	-	0.90	0.06	15	0.3	0.1	1.1	0.4	0.2	0.1	1.8
16-30	6.0	4.4	0.04	-	0.45	0.03	15	0.3	0.2	0.4	0.4	0.1	0.1	1
30-50	6.0	4.3	0.02	-	0.15	0.02	8	0.3	0.1	0.4	0.4	0.1	0.1	1
50-63	6.1	4.3	0.02	-	0.09	0	-	0.1	0.1	0.4	0.4	0.1	0.1	1
63-94	5.6	3.9	0.01	-	0.17	0	-	2.0	1.5	0.4	0.6	0.2	0.1	1.3
94-120	5.5	3.9	0.01	-	0.13	0	-	2.0	1.7	0.4	0.4	0.3	0.1	1.2

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 %
0-16	38	4.8	52	3.2	-	2	2
16-30	37	2.7	27	1.6	-	7	4
30-50	45	2.2	16	0.5	-	5	5
50-63	45	2.2	25	0.3	-	5	5
63-94	27	4.8	16	0.6	-	31	2
94-120	23	5.2	14	0.5	-	33	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
0-16	-	-	-	0.08	0	0.47	0.09	0.06	0.07	-	0.03
16-30	-	-	-	0.07	0	0.44	0.08	0.07	0.05	-	0.03
30-50	-	-	-	0.04	0	0.52	0.08	0.09	0.05	-	0.03
50-63	-	-	-	0.03	0	0.40	0.06	0.04	0.02	-	0.02
63-94	-	-	-	0.07	0	0.97	0.15	0.06	0.04	-	0.04
94-120	-	-	-	0.09	0	1.14	0.19	0.03	0.03	-	0.04

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
0-16	4.1	0.02	1.0	0.27	0.00	-	91.7	0.40
16-30	3.8	0.01	0.9	0.26	0.01	-	93.2	0.40
30-50	5.2	0.00	1.2	0.32	0.02	-	90.8	0.43
50-63	3.7	0.00	0.9	0.26	0.00	-	94.9	0.43
63-94	11.0	0.00	2.1	0.57	0.06	-	82.6	0.50
94-120	13.3	0.00	2.5	0.68	0.07	-	79.5	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
0-16	6.4	2.8	0.02	0.01	38	243.7	32.8
16-30	6.6	1.9	0.01	0.00	41.6	275.2	36.1
30-50	6.8	2.0	0.01	0.00	29.6	201.1	25.8
50-63	6.4	1.3	0.00	0.00	43.5	280.2	37.7
63-94	8.2	3.9	0.00	0.01	12.7	104.5	11.4
94-120	8.3	4.7	0.00	0.01	10.1	84.5	9.1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-16	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	weak	-	-	-
16-30	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	weak	-	-	-
30-50	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	weak	-	-	-
50-63	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	weak	-	-	-
63-94	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	weak	-	-	-
94-120	-	very weak to weak	-	weak to medium	-	-	very strong	weak to medium	weak	-	-	-

Profile description

Ah 0-16 cm	(dark) brown (10YR 4/3, dry) very dark greyish brown (10YR 3/2, moist)fine sand,single grain,soft very friable non sticky non plastic,many very fine to medium pores highly porous (>60 vol%),common fine and medium roots,non calcareous,clear smooth boundary to,
AC 16-30 cm	brown (7.5YR 5/4, dry) (dark) brown (7.5YR 4/4, moist)fine sand,single grain,soft very friable non sticky non plastic,many very fine and fine pores,common very fine to coarse roots,non calcareous,gradual wavy boundary to,
C 30-63 cm	reddish yellow (7.5YR 6/6, dry) yellowish red (5YR 5/6, moist)loamy sand,single grain,soft loose non sticky non plastic,many very fine and fine pores,few fine and medium roots,non calcareous,clear smooth boundary to,
2Btb 63-160 cm	light red (2.5YR 6/8, dry) red (2.5YR 4/6, moist)sandy clay loam,weak medium subangular blocky and weak coarse subangular blocky,very hard friable sticky plastic,patchy thin clay and sesquioxide cutans,many very fine and fine pores,few fine roots,non calcareous,

Depth1	63cm
Kind 1 (parent material) ; Parker (eds), 1984	sandstone
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)	residual material
Remarks on Parent Materials	Precambrian Kibaran System (Upper basement Complex)
Soil Depth	150cm
Texture of parent material	sandy
Texture of parent material (second entry)	loamy
Weathering Resistance	moderate
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

Occurrence of soil aggradation (McDonald et al., 1984)	present
Slope stability	stable

Land use or vegetation in the immediate vicinity of the site	woodland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Open savannah, dominant species Brachystegia boehmi, Anisodylles boehmi and Terminalia mollis. LAND USE: poor arable land, mainly dry due to textural limitations
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)	deciduous woodland

Altitude	1384m
Physiographic Unit	piedmont
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.	plateau
Slope	2%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-160cm
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	medium

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
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 Zambia 07: Regosol

Characteristics

Reference soil ZM007: Regosols

Classification