Reference soil Nigeria 11: Phaeozem

NG011

Phaeozems occur all over the world, but especially on the more moist side of the steppe regions, bordering Chernozems.

Characteristics

Soils having a mollic horizon (deep, brownish or blackish surface horizon with a significant accumulation of organic matter and high base saturation); a base saturation of 50 percent or more between 25 and 100 cm from the soil surface; a calcium carbonate-free soil matrix at least to a depth of 100 cm from the soil surface, or to a contrasting layer between 25 and 100 cm; no diagnostic horizons other than an albic, argic, cambic or vertic horizon, or a petrocalcic horizon in the substratum.

Distribution of Phaeozems (rough estimation supplied by soilgrids)

Reference soil NG011: Phaeozems

Brief description of the soil: A deep, poorly drained clayey soil with common cracks, pressure faces and slickensides; faint mottling occurs throughout the soil; horizontation is gradual, structure is moderate to strong developed. Physiographic unit: Seasonally inundated, almost flat to sloping region towards Niger river. Permeability: moderate before Niger was dammed up. Vegetation cover: grasses like Echinochlora pyramidalis, Vossia cuspidata. Flooding: Profile flooded 3 months a year during rainy season June to August/September. Additional notes to profile description: A11: Mottles appear also along rootchannels; cracks 0,5 cm wide. A12, B21, B22: Mottles discontinuous; common pressure faces. B3: Many interseckting slickensides with 60° angle with the horizontal; many pressure faces; few soft whitish accumulations. 2C: Weathered piece of schist, underlain by a fairly homogeneous clay layer. 3C: common white weathered rock (10 Yr 8/1). References: - Siderius, W.; Soil-vegetation relationships in the Borgu Game reserve. Wildlife Technical Report No.8. Kainji Lake Research Project, Jan. 1974. "vertic" (USDA) is a tentative subgroup. Climate data source: Agroclimatological data Africa 1, FAO. Rome 1984.

Classification

WRB 2006

WRB 1998

Luvic-Gleyic-Vertic- Phaeozem

Gleyi-Vertic- Phaeozem (Luvic)

25-110 cm	argic horizon
-	gleyic colour pattern
-	reducing conditions
-	vertic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Luvi-Gleyic Phaeozem

Gleyic Phaeozem

0-25 cm	mollic A horizon
25-110 cm	argic B horizon
-	gleyic
-	vertic

0-25 cm	mollic A horizon
25-110 cm	argillic B horizon
-	hydromorphic
-	vertic

Local classification:	Lake Kainji Series

Other classification

USDA-SCS (1975)

Tropaqualf ustic 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
0-5	-	2.4	3.7	8.5	25.6	18.5	58.7	19.7	9.0	28.7	12.8
5-25	-	5.5	6.5	9.4	23.6	15.2	60.2	15.6	6.6	22.2	17.6
25-45	-	4.9	5.3	7.9	18.3	13.3	49.7	18.3	10.8	29.1	21.1
45-75	-	1.4	2.1	4.8	12.2	9.7	30.2	19.2	21.0	40.2	29.6
75-110	-	1.0	1.9	4.2	12.8	10.0	29.9	17.4	19.9	37.3	32.8
200-250	-	2.4	2.4	3.3	5.9	6.5	20.5	13.4	28.8	42.2	37.4

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-5	-	-	-	-	12.8
5-25	-	-	-	-	17.6
25-45	-	-	-	-	21.1
45-75	-	-	-	-	29.6
75-110	-	-	-	-	32.8
200-250	-	-	-	-	37.4

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
0-5	5.6	4.3	0.14	0.2	1.01	0.05	20	-	-	4.9	1.5	0.1	0.0	6.5
5-25	6.5	5.2	0.11	0.1	0.64	0.04	16	-	-	7.1	4.2	0.1	0.0	11.4
25-45	6.8	5.2	0.09	0.4	0.45	0.04	11	-	-	7.3	5.5	0.1	0.1	13
45-75	7.5	5.7	0.14	1.1	0.34	0.02	17	-	-	10.9	10.0	0.3	0.4	21.6
75-110	7.9	6.2	0.17	1.3	0.31	0.03	10	-	-	10.7	11.8	0.3	0.4	23.2
200-250	8.2	5.7	0.16	3.1	0.15	0.01	15	-	-	27.6	23.3	0.2	1.2	52.3

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 %
0-5	33	19.7	154	3.5	-	-	0
5-25	89	12.8	73	2.2	-	-	0
25-45	90	14.5	69	1.6	-	-	1
45-75	96	22.6	76	1.2	-	-	2
75-110	97	24.0	73	1.1	-	-	2
200-250	99	52.7	141	0.5	-	-	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
0-5	9.6	2.65	3.1	1.21	0.55	1.17	75.6	0.54
5-25	10.5	2.43	3.9	1.26	0.52	1.14	75.7	0.51
25-45	11.5	2.65	4.7	1.16	0.59	1.18	74.4	0.63
45-75	13.6	3.06	5.2	1.30	0.96	1.36	67.7	0.87
75-110	14.4	2.72	4.9	1.17	0.90	1.45	68.9	0.84
200-250	16.7	3.59	7.1	1.41	2.74	-	59.0	0.64

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
0-5	4.9	3.3	0.06	0.03	13.4	64.8	11.1
5-25	4.2	3.4	0.07	0.02	12.2	51.6	9.9
25-45	3.8	3.6	0.19	0.02	11	42.1	8.7
45-75	4.1	4.2	0.17	0.01	8.4	34.6	6.8
75-110	4.6	4.7	0.06	0.01	8.1	37.4	6.7
200-250	3.7	6.3	0.07	0.16	6	22.1	4.7

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-5	-	very weak to weak	-	-	-	-	medium	very weak	very weak	very weak	strong	-
5-25	-	very weak to weak	-	-	-	-	very strong	very weak	weak to medium	very weak	strong	-
25-45	-	very weak to weak	-	-	-	-	medium	very weak	weak to medium	very weak	strong	-
45-75	-	very weak to weak	-	-	-	-	medium	very weak	very weak	very weak	strong	-
75-110	-	very weak to weak	-	-	-	-	medium	weak	weak to medium	very weak	strong	-
200-250	-	very weak to weak	-	-	-	-	weak to medium	weak to medium	weak to medium	-	very strong	-

Profile description

Ah1 0-5 cm	dark greyish brown (10YR 4/2, dry) black (10YR 2/1, moist)loam,moderate medium subangular blocky and weak medium platy,hard friable non sticky plastic,common (5-15%) faint mottles 5.0YR5/8 (Invalid Code:),many fine tubular pores,slightly calcareous (02%),gradual smooth boundary to,
Ah2 5-25 cm	dark greyish brown (10YR 4/2, dry) very dark greyish brown (10YR 3/2, moist)slightly gravelly loam,weak medium subangular blocky,very hard friable slightly sticky plastic,few (2-5%) faint mottles 10YR3/4 (dark yellowish brown),patchy thin pressure cutans,common fine tubular pores,slightly calcareous (0-2%),gradual smooth boundary to,
Bw1 25-45 cm	brown (10YR 5/3, dry) dark greyish brown (10YR 4/2, moist)slightly gravelly clay,coarse prismatic,hard firm sticky plastic,few (2-5%) faint heterogeneous distinct mottles,patchy thin clay cutans in root channels and pores,few fine gravel sand grains fragments,slightly calcareous (0-2%),gradual smooth boundary to,
Bw2 45-75 cm	very dark grey (10YR 3/1, dry) dark grey (10YR 4/1, moist)slightly gravelly clay,strong medium subangular blocky and strong medium angular blocky,very hard firm sticky plastic,common (5-15%) faint mottles 10YR5/6 (yellowish brown),patchy thin clay cutans,few fine gravel sand grains fragments,slightly calcareous (0-2%),gradual smooth boundary to,
75-110 cm	dark greyish brown (10YR 4/2, dry) greyish brown (10YR 5/2, moist)clay,strong fine and medium angular blocky,very hard firm sticky plastic,few (25%) faint mottles 10YR5/4 (yellowish brown),continuous thin slickensides,few small ferruginous concretions,few fine gravel,slightly calcareous (0-2%),clear smooth boundary to,
2C 110-120 cm	brown (10YR 5/3, dry) brown (10YR 5/3, moist)clay stones,slightly gravelly clay,hard firm slightly sticky plastic,many mottles (7.5YR 5/8),dominant coarse gravel and stones strongly weathered pieces of schist,few fine gravel angular quartz frequent weathered weathered rock fragments,slightly calcareous (0-2%),slightly calcareous (0-2%),

Kind 1 (parent material) ; Parker (eds), 1984	gneiss
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	Basement complex
Texture of parent material	clayey
Texture of parent material (second entry)	clayey
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	Grassland seasonally inundated; grasses: Echinochlora pyramidalis, Vossia cuspidata. Area flooded 3 months a year during June to August/September
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	degraded
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	short grassland

Altitude	141m
Physiographic Unit	beach
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.	lacustrine plain
Slope	2%
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	poor
Dry From - To	0-20cm
Flooding frequency (FAO, 1986)	yearly
Nature of flood water	fresh
(Estimated) maximum (lower) depth to groundwater table	200cm
Depth to groundwater table	175cm
Kind of ground water table (USDA, 1979)	groundwater table observed
(Estimated) minimum (upper) depth to groundwater table	0cm
Moist From - To	20-175cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow
Wet From To	175-200cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Surface cracking	small cracks (width less than 1 cm, or depth less than 50 cm)
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

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Reference soil Nigeria 11: Phaeozem

Characteristics

Reference soil NG011: Phaeozems

Classification