Reference soil Zimbabwe 07: Gleysol

ZW007

Gleysols occur throughout the world where groundwater comes near to the surface, causing soils to become wet for a prolonged part of the year. They are particularly abundant in the low-lying river basins.

Characteristics

Soils having gleyic properties (properties associated with prolonged wetness) within 50 cm from the soil surface. They have no diagnostic horizons other than an anthraquic, histic, mollic, ochric, takyric, or umbric horizon at the surface, or an andic, calcic, cambic, gypsic, plinthic, salic, sulfuric, or vitric horizon within 100 cm from the soil surface.

Distribution of Gleysols (rough estimation supplied by soilgrids)

Reference soil ZW007: Gleysols

(1) Profile has been located within one of the Pasture Blocks on Henderson Research Station. The relative position of the site on the landscape slope has been assessed as a lowerslope position. The semi-natural grass cover does not include sedge varieties, which are found lower down the slope. (2) The grass vegetation is dominantly Hyperrhenia sp. (3) Cattle have been excluded from the Block for a period, so a good stand of grass remains. (4) The dominant landform of the area is described as low-lying pediments between the Iron Mask Range in the west and the Blue Granite Hills in the east. The Iron Mask Range runs in an approximately NE to SW direction, and in the southwest, consists of a single, narrow range with steep sides and a very narrow summit from 1550 to 1640 metres in height. In between the two ranges of hills, flows the Dasura River. The granite hills in the east are of rugged and broken aspect, rise up to 1560 metres in height, and are typically "castle kopje" country with the occasional dome-shaped hill. (5) Lister indicates that the area occurs on the Post African Erosion Surface. (6) The geology of the area is very mixed, but in general, the soils around the site of the profile can be said to be derived from in-situ sediments of the Iron Mask Series and fine-grained quartzo-felspathic meta volcanics. These parent materials contain a high proportion of silt-sized particles. (7) The grass vegetation and root patterns successfully stabilize the surface layers of the profile. If this protection were removed, the surface horizons would be very prone to capping, sealing and hardsetting. (8) The area around the profile shows evidence of old cattle track lines, which are orientated downslope towards lower drainage lines or depressions. (9) The profile horizons show much evidence for high watertables. In the uppermost horizons, root channel staining can be observed. With depth, increasing concentrations of mottles and iron/manganese concretions are observed. (10) The uppermost horizon of the profile, from 0 to 2 cms, is composed of moderately decomposed organic matter, derived from grasses. (11) Grass roots are evident throughout the profile, and are found both within peds and around peds. Dead roots within peds leave noticeable black discolorations. (12) The seventh horizon was not sampled for analysis, as it contained significant amounts of concretionary and stony material. (13) Under normal seasons, a higher moisture or watertable might be expected, given the low-lying position of the site and its imperfect drainage characteristicsations

Classification

WRB 2006

Haplic- Gleysol (Eutric Siltic)

34-90 cm	cambic horizon
-	gleyic colour pattern
-	reducing conditions

34-90 cm	cambic horizon
-	gleyic colour pattern
-	reducing conditions

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Silti-Eutric Gleysol

Eutric Gleysol

0-34 cm	ochric A horizon
34-90 cm	cambic B horizon
-	gleyic

0-34 cm	ochric A horizon
34-90 cm	cambic B horizon
-	hydromorphic

Local classification:	Mazowe 5S.4 series

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
2-12	1	1.6	2.9	3.3	5.6	6.3	19.7	16.2	36.3	52.5	27.8
12-34	0	1.3	2.5	3.3	6.2	5.5	18.8	15.2	35.8	51	30.2
34-45	0	2.5	8.7	3.8	4.8	4.7	24.5	12.8	27.6	40.4	35.1
45-65	11	3.9	3.9	4.0	5.2	3.9	20.9	12.9	28.6	41.5	37.7
65-90	16	4.6	4.1	3.4	4.4	3.6	20.1	11.6	29.6	41.2	38.7
90-98	-	7.2	18.8	17.8	18.4	8.8	71.0	8.7	5.4	14.1	14.9
98-117	17	4.1	4.8	3.7	4.3	4.4	21.3	12.4	27.6	40	38.7
117-150	6	3.3	4.3	3.9	4.4	5.0	20.9	13.6	29.7	43.3	35.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
2-12	1.27	-	-	11.2	27.8
12-34	1.35	-	-	18.2	30.2
34-45	1.45	-	-	25.9	35.1
45-65	1.44	-	-	28.9	37.7
65-90	1.56	-	-	27.7	38.7
90-98	-	-	-	10.3	14.9
98-117	1.54	-	-	25.4	38.7
117-150	1.50	-	-	26.7	35.8

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
2-12	1.27	-	-	37	35	21	-	20	19
12-34	1.35	-	-	32	31	22	-	19	16
34-45	1.45	-	-	29	28	23	-	17	16
45-65	1.44	-	-	30	29	24	-	16	15
65-90	1.56	-	-	30	29	25	-	14	15
98-117	1.54	-	-	31	30	27	-	19	12
117-150	1.50	-	-	31	30	25	-	-	15

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
2-12	5.9	4.7	0.08	-	2.87	0.20	14	-	-	6.7	3.4	0.3	0.1	10.5
12-34	6.2	5.1	0.07	-	1.41	0.10	14	-	-	6.5	3.7	0.2	0.2	10.6
34-45	6.5	5.2	0.05	-	0.61	0.04	15	-	-	4.9	3.7	0.2	0.1	8.9
45-65	6.5	5.3	0.06	-	0.32	0.03	11	-	-	4.3	3.4	0.2	0.1	8
65-90	6.7	5.4	0.06	0.6	0.29	0.03	10	-	-	4.3	3.4	0.2	0.1	8
90-98	5.7	4.7	0.05	-	0.52	0.05	10	-	-	2.2	1.3	0.8	0.1	4.4
98-117	6.5	5.4	0.05	-	0.16	0.02	8	-	-	4.3	3.4	0.2	0.1	8
117-150	6.5	5.4	0.08	-	0.12	0.02	6	-	-	4.1	3.0	0.2	0.1	7.4

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 %
2-12	88	11.9	43	10.0	-	-	1
12-34	98	10.8	36	4.9	-	-	2
34-45	105	8.5	24	2.1	-	-	1
45-65	79	10.1	27	1.1	-	-	1
65-90	107	7.5	19	1.0	-	-	1
90-98	79	5.6	38	1.8	-	-	2
98-117	107	7.5	19	0.6	-	-	1
117-150	95	7.8	22	0.4	-	-	1

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
2-12	-	-	-	-	-	-	very strong	medium to strong	-	-	very weak to weak	-
12-34	-	-	-	very weak	-	-	very strong	medium to strong	-	-	very weak to weak	-
34-45	-	-	-	weak	-	-	very strong	medium to strong	-	-	very weak to weak	-
45-65	-	-	-	weak	-	-	very strong	medium to strong	-	-	very weak to weak	-
65-90	-	-	-	weak	-	-	very strong	medium to strong	-	-	very weak to weak	-
90-98	-	-	-	very weak to weak	-	-	very strong	weak to medium	-	-	weak	-
98-117	-	-	-	weak	-	-	very strong	medium to strong	-	-	very weak to weak	-
117-150	-	-	-	weak	-	-	very strong	medium to strong	-	-	very weak to weak	-

Profile description

O 0-2 cm	very dark grey (2.5Y 3/0, moist) grey (10YR 5/1, dry)very dark grey (2.5Y 3/0, moist) grey (10YR 5/1, dry),silty clay loam,organic moderately decomposed herbaceous fragments,structureless,moderate medium angular blocky,very hard sticky plastic strongly smeary,no cutans,common fine roots,many fine roots,many fine roots,no inclusions,no fragments,non calcareous,non calcareous,gradual wavy boundary to,clear wavy boundary to,
12-34 cm	very dark grey (2.5Y 3/0, moist) grey (10YR 5/1, dry)silty clay loam,strong medium prismatic parting to strong medium angular blocky,very hard sticky plastic strongly smeary,no cutans,no inclusions,no fragments,non calcareous,clear wavy boundary to,
Bg1 34-45 cm	very dark grey (2.5Y 3/0, moist) grey (10YR 5/1, dry)silty clay loam,strong coarse prismatic parting to strong medium angular blocky,extremely hard sticky plastic strongly smeary,common (5-15%) fine distinct clear mottles 10YR4/6 (dark yellowish brown),no cutans,many fine roots,very few small spherical hard manganiferous concretions,no fragments,non calcareous,gradual wavy boundary to,
Bg2 45-65 cm	very dark grey (2.5Y 3/0, moist) grey (10YR 5/1, dry)silty clay loam,strong coarse prismatic parting to strong medium angular blocky,extremely hard sticky plastic strongly smeary,common (5-15%) fine distinct clear mottles 10YR4/6 (dark yellowish brown),no cutans,common fine roots,few small spherical hard manganiferous concretions,no fragments,non calcareous,gradual wavy boundary to,
Bg3 65-90 cm	dark grey (2.5Y 4/0, moist) grey (10YR 5/1, dry)clay,weak to moderate medium prismatic parting to moderate medium angular blocky,hard sticky plastic strongly smeary,many (15-40%) medium distinct clear mottles 10YR5/8 (yellowish brown) 7.5YR5/8 (strong brown),no cutans,common fine roots,few medium spherical hard manganiferous concretions,very few fine gravel weathered quartz fragments,no,non calcareous,clear wavy boundary to,
90-98 cm	dark grey (2.5Y 4/0, moist) grey (10YR 5/1, dry)clay gravelly,moderately coherent massive,hard sticky plastic strongly smeary,many (15-40%) medium distinct clear mottles 10YR5/8 (yellowish brown) 7.5YR5/8 (strong brown),no cutans,common fine roots,few medium spherical hard manganiferous concretions,few fine gravel weathered quartz fragments,non calcareous,clear wavy boundary to,
CB 98-117 cm	dark grey (2.5Y 4/greyish brown (2.5Y 5/2, dry)slightly gravelly clay,moderately coherent massive,firm sticky plastic strongly smeary,many (15-40%) medium prominent sharp mottles 10YR4/6 (dark yellowish brown) 7.5YR5/8 (strong brown),no cutans,few fine roots,few medium spherical hard manganiferous concretions,few fine gravel weathered quartz fragments,non calcareous,diffuse wavy boundary to,
Cg 117-150 cm	greyish brown (2.5Y 5/2, dry) (2.5Y 4/1, moist)slightly gravelly silty clay loam,moderately coherent massive,firm sticky plastic strongly smeary,many (15-40%) coarse prominent sharp mottles 7.5YR4/6 (strong brown),no cutans,few fine and fine roots,few fine roots,few medium spherical hard manganiferous concretions,few fine gravel weathered quartz fragments,non calcareous,

Depth1	90cm
Kind 1 (parent material) ; Parker (eds), 1984	metamorphic/sedimentary rock
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	metasediments
Soil Depth	150cm
Texture of parent material	silty
Weathering Resistance	poor
General characterization of the status of weathering of solid rock	highly

Occurrence of soil aggradation (McDonald et al., 1984)	not apparent
Intensity of the soil erosion type	slight
Soil erosion type	sheet
Slope stability	stable

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: Grassland modified by grazing trials. Grass vegetation is predominantly Hyperrhenia sp.
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)	modified
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	medium tall grassland

Altitude	1240m
Physiographic Unit	pediment of Iron Mask Range
Physiographic position of the site	lower slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	pediment
Slope	2%
Slope Aspect	east
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Lower limit of a slow permeable or stagnating layer in the profile	98cm
Drainage class ; FAO (2006) - Guidelines for soil description	imperfect
Dry From - To	0-98cm
Flooding frequency (FAO, 1986)	never
(Estimated) maximum (lower) depth to groundwater table	150cm
Depth to groundwater table	0cm
Kind of ground water table (USDA, 1979)	apparent
(Estimated) minimum (upper) depth to groundwater table	34cm
Moist From - To	98-150cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	slow
Upper limit of a slow permeable or stagnating layer in the profile	90cm

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)
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	no surface slaking/crusting observed
Microrelief Height: variation in height	6
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	animal tracks
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 Zimbabwe 07: Gleysol

Characteristics

Reference soil ZW007: Gleysols

Classification