Reference soil Zimbabwe 02: Ferralsol

ZW002

Ferralsols occur in tropical and subtropical regions of the world, mainly on old and stable land surfaces.

Characteristics

Soils having a ferralic horizon (strongly weathered horizon with low-activity clays and very low amounts of weatherable minerals) between 25 and 200 cm from the soil surface. They lack a nitic horizon (a horizon with strongly developed, nut-shaped structure) and do not have a layer which fulfils the requirements of an argic horizon and which has, in the upper 30 cm, 10 percent or more water-dispersible clay.

Distribution of Ferralsols (rough estimation supplied by soilgrids)

Reference soil ZW002: Ferralsols

(1)The site would normally be under natural woodland, dominated by Julbernardia globiflora, Parinara curatellifolia and Uapaca kirkiana. This woodland has been cleared by the local population, and grasses and shrubs have regrown. The main grass species is Hyperthelia dissoluta, with some Aristida meridionalis. The shrub species include Uapaca kirkiana, Tephrosia rhodesica, Rhynchosia resinosa, Strynos spinosa, Acacia nilotica, Julbernardia globiflora (dominant), Lantana camara, Dichrostacys cinerea, Parinara curatell- ifolia and Clerodendrum glabrum. In addition, a number of herbaceous species were identified - Tagetes minuta, Blumea crispata and Vernonia glabra, Trichodesma physaloides and Aspilia pluriseta. (2)A nearby stand of Eucalyptus regrowth was observed. (3)Evidence of fire burns in the vicinity of the pit were observed. (4)Area has been lightly grazed by a small herd of cattle. (5)A road drainage cutting is situated about 5 m from the pit, and was constructed in 1988, when the road past Epworth Mission Station was sealed. (6)Lister (1986,p.82) indicates that the Epworth area is situated on the African Erosion Surface, and that the regularly jointed granite boulders and balancing rocks are residua from the Post-Gondwana Erosion Surface. (7)The pit terminates at about 160 cms onto many, coarse to very coarse, moderately weathered, granite boulders. (8)Horizon 7 has been designated Cw because of the observed presence of remnant rock structures, although there is little evidence of actual rock fragments. (9)Under the headings of biological activity, the following comments must be made: in Horizons 1 and 2, termite and ant channels were observed; in Horizons 3 and 4, krotovinas of varying dimensions were noted and in addition, plant root channels stained black as a result of the decomposition of the root material; in Horizons 5 and 6, similar darkened channels from decomposed roots were observed; no biological activity was recorded in Horizon 7. (10)A number of insect specimens were taken for identification. Two beetle (Coleoptera) specimens included (Tenebrionidae Opatrinae) Anomalipus mustela and (Carabidae Graphopterinae) Piezia mashuna. Two ant specimens included (Formicidae Ponerinae) Paltothyreus tarsatus, (Formicidae Myrmicinae) Tetramonium sp, and the one termite (Isoptera) specimen could not be identified adequately.

Classification

WRB 2006

Lixic-Vetic- Ferralsol (Eutric Clayic)

30-125 cm

ferralic horizon

30-125 cm

ferralic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Veti-Haplic Ferralsol

Orthic Ferralsol

0-30 cm	ochric A horizon
30-99 cm	ferralic B horizon
99-125 cm	cambic B horizon
-	weatherable minerals

0-30 cm	ochric A horizon
30-125 cm	oxic B horizon
-	weatherable minerals

Local classification:	Harare 6G.2

Other classification

USDA-SCS (1975)

Eutrustox ustic sandy over clayey halloysitic isothermic

Land use

Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	land clearing
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	no irrigation
Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Natural woodland replaced by grasses. Main grass species: Hyperthelia dissoluta, with some Aristida meridionalis. Shrub species: Uapaca kirkiana, Tephrosia rhodesica, Rhynchosia resinosa, Strynoapinosa, Acacia nilotica, Julbernardia globiflora (dominant), Lantana camara, Dichrostacys cinera, Parinara curatellifolia and Clerodendrum glabrum. Herbaceous species: Tagetes minuta, Blumea crispata and Vernonia glabra, Trichodesma physaloides and Aspilia pluriseta.
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	cut over
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	medium tall grassland

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
0-14	-	7.9	23.0	20.8	19.6	7.5	78.8	4.1	3.1	7.2	14.1
14-30	-	9.9	26.4	18.8	15.4	4.6	75.1	2.6	4.1	6.7	18.2
30-60	-	7.3	18.3	10.6	8.8	4.5	49.5	4.9	3.5	8.4	42.1
60-81	-	10.1	16.9	10.3	9.7	3.9	50.9	3.3	5.0	8.3	40.7
81-99	-	9.5	15.0	9.1	9.8	6.3	49.7	2.8	5.4	8.2	42.1
99-125	-	11.9	13.1	7.3	9.3	5.8	47.4	3.8	6.5	10.3	42.3
125-150	-	13.6	13.1	6.4	8.4	6.4	47.9	3.4	7.4	10.8	41.4

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-14	1.45	-	-	9.2	14.1
14-30	1.51	-	-	13.3	18.2
30-60	1.51	-	-	3.4	42.1
60-81	1.48	-	-	2.9	40.7
81-99	1.47	-	-	2.1	42.1
99-125	-	-	-	0.5	42.3
125-150	-	-	-	0.4	41.4

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
0-14	1.45	-	-	14	12	9	-	8	6
14-30	1.51	-	-	23	21	18	-	16	15
30-60	1.51	-	-	23	21	18	-	16	15
60-81	1.48	-	-	25	23	19	-	17	15
81-99	1.47	-	-	28	25	20	-	18	16

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
0-14	5.2	4.9	0.47	-	0.42	0.03	14	0.2	0	1.2	0.3	0.1	0.0	1.6
14-30	5.1	4.9	0.09	-	0.26	0.01	26	0.2	0	0.6	0.3	0.1	0.0	1
30-60	5.1	4.8	0.08	-	0.18	0.00	-	0.2	0	1.4	0.7	0.1	0.0	2.2
60-81	5.2	4.9	0.06	-	0.10	0.01	10	0.1	0	1.2	0.7	0.1	0.0	2
81-99	5.2	4.8	1.00	-	0.09	0.00	-	0.1	0	1.2	0.7	0.1	0.1	2.1
99-125	5.0	4.8	0.10	-	0.08	0.01	8	0.1	0	1.4	0.7	0.3	0.1	2.5
125-150	5.2	5.0	0.04	-	0.05	0.01	5	0.1	0	1.6	0.7	0.1	0.0	2.4

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 %
0-14	70	2.3	16	1.5	-	0	0
14-30	71	1.4	8	0.9	-	0	0
30-60	56	3.9	9	0.6	-	0	0
60-81	63	3.2	8	0.4	-	0	0
81-99	100	2.1	5	0.3	-	0	5
99-125	89	2.8	7	0.3	-	0	4
125-150	86	2.8	7	0.2	-	0	0

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-14	-	very weak	-	weak to medium	-	-	very strong	weak	-	-	-	-
14-30	-	very weak	-	weak to medium	-	-	very strong	weak	-	-	-	-
30-60	-	-	-	weak to medium	-	-	very strong	very weak to weak	-	-	-	-
60-81	-	-	-	weak to medium	-	-	very strong	very weak to weak	-	-	-	-
81-99	-	-	-	weak to medium	-	-	very strong	very weak	-	-	-	-
99-125	-	-	-	weak to medium	-	-	very strong	very weak	-	-	-	-
125-150	-	-	-	weak to medium	-	-	very strong	very weak	-	-	-	-

Profile description

Ah 0-14 cm	brown (7.5YR 5/4, dry) dark brown (7.5YR 3/4, moist)coarse sandy loam,moderate fine and medium subangular blocky and weak to moderate medium and coarse single grain,loose (dry),no cutans,many very fine and fine roots,no inclusions,no fragments,few termite channels and channels,non calcareous,clear smooth boundary to,
14-30 cm	brown (7.5YR 5/4, dry) (dark) brown (7.5YR 4/4, moist)coarse sandy loam,moderate fine and medium subangular blocky,slightly hard (dry),no cutans,common very fine and fine roots,no inclusions,no fragments,few termite channels and channels,non calcareous,clear smooth boundary to,
Bw1 30-60 cm	yellowish red (5YR 5/6, dry) yellowish red (5YR 4/6, moist)sandy clay loam,weak to moderate fine and medium subangular blocky,very hard (dry),no cutans,common medium roots,no inclusions,no fragments,few krotovinas and channels,non calcareous,clear wavy boundary to,
Bw2 60-81 cm	yellowish red (5YR 5/6, dry) yellowish red (5YR 4/6, moist)sandy clay loam,weak to moderate fine and medium subangular blocky,hard (dry),no cutans,common medium roots,no inclusions,very few coarse gravel weathered Granite fragments,few krotovinas and channels,non calcareous,gradual smooth boundary to,
Bw3 81-99 cm	reddish yellow (5YR 6/8, dry) yellowish red (5YR 5/8, moist)sandy clay loam,moderately coherent porous massive,slightly hard (dry),no cutans,few fine and medium roots,no inclusions,no fragments,few channels,non calcareous,gradual smooth boundary to,
Bw4 99-125 cm	reddish yellow (5YR 6/8, dry) yellowish red (5YR 5/8, moist)sandy clay loam,weakly coherent porous massive,soft (dry),no cutans,few fine and medium roots,no inclusions,no fragments,few channels,non calcareous,gradual wavy boundary to,
C 125-150 cm	reddish yellow (5YR 6/8, dry) yellowish red (5YR 5/8, moist)sandy clay loam,weakly coherent porous massive,soft (dry),no cutans,few fine roots,no inclusions,few fine gravel strongly weathered feldspar and few fine gravel weathered quartz fragments,no,non calcareous,

Depth1	160cm
Kind 1 (parent material) ; Parker (eds), 1984	coarse-grained acid igneous rock
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	jointed granite
Soil Depth	160cm
Texture of parent material	sandy
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	partially or moderately

Occurrence of soil aggradation (McDonald et al., 1984)	absent
Intensity of the soil erosion type	slight
Soil erosion type	sheet
Slope stability	stable

Altitude	1516m
Physiographic Unit	low granite balancing rocks
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.	plateau
Slope	2%
Slope Aspect	south-south-east
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	0-160cm
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	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 Height: variation in height	13
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	holes
Microrelief pattern	isolated
Rock outcrop class (FAO (2006) - Guidelines for soil description)	rocky
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 Zimbabwe 02: Ferralsol

Characteristics

Reference soil ZW002: Ferralsols

Classification