Reference soil Zambia 03: Acrisol

ZM003

Acrisols occur dominantly in the wetter parts of the tropics and subtropics and the warm temperate regions in relatively young landscapes.

Characteristics

Soils having an argic horizon (a subsurface horizon with distinct higher clay content than the overlying horizon), which has a cation exchange capacity of less than 24 cmolc per kg in some part, either starting within 100 cm from the soil surface, or within 200 cm from the soil surface if the argic horizon is overlain by loamy sand or coarser textures throughout. They have a base saturation (total amount of Ca, Mg, K and Na with respect to the cation exchange capacity) of less than 50 percent in the major part between 25 and 100 cm from the soil surface

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil ZM003: Acrisols

FAO - medium textured - No oxic horizon because of (1) too high CEC, (2) too high water dispersible clay in subsoil. - Textural analyses indicate : Argillic B horizon. LOCATION: 2.5 km W of Kiwambe Mission along Mbala-Kiwambe road. Termite mounds average base diameter 8 m, distance 80 m; reddish colour. HUMAN INFLUENCE: Ploughing, indicated by abrupt boundary at 25 cm.

Classification

WRB 2006

Vetic- Acrisol (Hyperdystric Clayic Chromic)

28-120 cm

argic horizon

28-120 cm

argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Veti-Haplic Acrisol

Ferric Acrisol

0-45 cm	ochric A horizon
28-120 cm	argic B horizon

0-45 cm	ochric A horizon
28-120 cm	argillic B horizon
-	ferric

Local classification:	Mbala loam

Other classification

USDA-NRCS (1999)	Paleustult
USDA-SCS (1975)	Haplustult ustic clayey kaolinitic isothermic

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
0-17	-	1.1	6.9	12.8	11.1	8.0	39.9	31.3	6.4	37.7	22.4
17-28	-	1.7	7.4	12.4	9.4	7.0	37.9	29.3	7.8	37.1	25.1
28-45	-	1.2	5.9	8.5	6.1	5.1	26.8	25.8	6.3	32.1	41.1
45-60	-	1.1	5.3	7.7	5.9	4.9	24.9	25.2	5.2	30.4	44.8
60-80	-	1.0	5.4	7.7	6.1	5.0	25.2	26.0	6.0	32	42.8
80-120	-	1.4	5.7	6.4	5.6	6.0	25.1	28.9	7.1	36	39.0

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
5-10	1.219	-	-	-	-
0-17	-	32	-	9.5	22.4
17-28	-	35	-	9.5	25.1
40-45	1.409	-	-	-	-
28-45	-	54	-	13.0	41.1
80-85	1.238	-	-	-	-
45-60	-	58	-	4.5	44.8
60-80	-	56	-	1.5	42.8
80-120	-	51	-	4.5	39.0

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
5-10	1.219	47.5	45.7	36.6	26.9	23.2	18.5	7.1	6.2
40-45	1.409	38.1	38.7	34.3	28.0	24.8	21.5	15.4	13.7
80-85	1.238	47.3	46.2	38.2	28.1	24.2	20.7	13.2	12.2

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
0-17	5.8	4.7	0.05	-	0.90	0.06	15	0.2	0.2	1.2	0.6	0.3	0.0	2.1
17-28	5.8	4.6	0.05	-	0.75	0.05	15	0.2	0.1	1.2	0.5	0.4	0.0	2.1
28-45	6.0	4.6	0.03	-	0.49	0.01	49	0.2	0.1	0.4	0.6	0.5	0.0	1.5
45-60	6.0	4.7	0.03	-	0.32	-	-	0.2	0	0.8	0.8	0.5	0.0	2.1
60-80	5.8	4.8	0.02	-	0.23	-	-	0.1	0	0.0	0.8	0.4	0.0	1.2
80-120	6.1	5.0	0.02	-	0.15	-	-	0.1	0	0.2	0.7	0.3	0.0	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 %
0-17	26	8.1	36	3.2	-	2	0
17-28	27	7.9	31	2.6	-	1	0
28-45	18	8.4	20	1.7	-	1	-
45-60	23	9.2	21	1.1	-	0	0
60-80	14	8.6	20	0.8	-	0	0
80-120	18	6.8	17	0.5	-	0	0

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
0-17	-	-	-	0.10	0	1.44	0.18	0.08	0.05	-	0.14
17-28	-	-	-	0.12	0	1.57	0.20	0.09	0.05	-	0.14
28-45	-	-	-	0.14	0	1.84	0.27	0.08	0.05	-	0.11
45-60	-	-	-	0.14	0	1.90	0.29	0.05	0.06	-	0.10
60-80	-	-	-	0.14	0	1.82	0.30	0.02	0.03	-	0.09
80-120	-	-	-	0.12	0	1.67	0.25	0.02	0.03	-	0.07

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
0-17	8.3	0.04	2.8	0.80	0.07	-	85.2	0.40
17-28	9.5	0.05	3.2	0.91	0.08	-	83.7	0.44
28-45	14.6	0.03	4.1	0.82	0.10	-	76.3	0.57
45-60	15.6	0.03	4.2	0.75	0.07	-	74.2	0.59
60-80	15.5	0.01	4.2	0.78	0.08	-	74.7	0.58
80-120	13.8	0.01	3.8	0.80	0.08	-	77.0	0.56
120-	20.1	0.87	7.5	3.80	1.22	-	58.8	0.77

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
0-17	4.6	4.5	0.05	0.02	17.4	80.9	14.3
17-28	4.7	4.8	0.05	0.02	15	69.6	12.3
28-45	5.6	6.1	0.03	0.03	8.9	49.5	7.5
45-60	5.8	6.3	0.02	0.02	8.1	47.0	6.9
60-80	5.8	6.0	0.02	0.01	8.2	47.3	7.0
80-120	5.7	5.4	0.02	0.01	9.5	53.9	8.1
120-	4.2	8.1	0.12	0.13	5	20.9	4.0

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-17	-	-	-	weak	-	-	very strong	very weak to weak	-	very weak	-	-
17-28	-	-	-	weak	-	-	very strong	weak	-	very weak	-	-
28-45	-	-	-	weak	-	-	very strong	weak	-	very weak	-	-
45-60	-	-	-	weak	-	-	very strong	weak	-	very weak	-	-
60-80	-	-	-	weak	-	-	very strong	weak	-	very weak	-	-
80-120	-	-	-	weak	-	-	very strong	weak	-	very weak	-	-

Rare clay minerals

Depth (cm)	Amphibole	Augite	Calcite	Lepidococrite	Pyrophillite	Pyroxene	Weddelite
28-45	-	-	-	-	very weak to weak	-	-

Profile description

Ap 0-25 cm	(dark) brown (7.5YR 4/4, moist)loam,moderate fine and medium subangular blocky,slightly hard,many micro to fine pores,common fine and medium roots,frequent biological activity,non calcareous,abrupt smooth boundary to,
25-45 cm	reddish brown (5YR 4/4, moist)clay,moderate medium and coarse subangular blocky,extremely hard,many micro and very fine pores,few fine roots,non calcareous,gradual wavy boundary to,
Bt1 45-82 cm	(5YR 4/8, moist)clay,weak to moderate medium and coarse subangular blocky,soft,many micro to fine pores,few fine roots,non calcareous,diffuse smooth boundary to,
Bt2 82-140 cm	(5YR 4/8, moist)clay loam,soft,many micro pores,non calcareous,

Kind 1 (parent material) ; Parker (eds), 1984	coarse-grained intermediate igneous
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	porphyry
Soil Depth	150cm
Texture of parent material	clayey
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

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

Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	ploughing
Land use or vegetation in the immediate vicinity of the site	non-agricultural land
Remarks on Land Use / Vegetation	VEGETATION: Elephant grass with Triumfetta trifida
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	1750m
Physiographic Unit	gentle slope
Physiographic position of the site	slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plateau
Slope	3%
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	0-140cm
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
Surface cracking	no cracks observed
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Microrelief Height: variation in height	400
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	termite/ant mounds
Microrelief pattern	isolated
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 03: Acrisol

Characteristics

Reference soil ZM003: Acrisols

Classification