Reference soil Zimbabwe 13: Gleysol

ZW013

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 ZW013: Gleysols

(1) The natural vegetation mix is different from that of ZW11 and ZW12, and would more correctly be characterised as wooded grassland. The medium-sized trees and shrubs are both deciduous and semi-deciduous, and the grasses are a mixture of annual and perennial species. Brachystegia and Julbernardia species no longer dominate the tree/shrub mix whilst Terminalia sericea trees and shrubs are more evident. Vegetation samples were collected from the immediate vicinity outside the perimeter fence of the Block, and await full identification. (2) Only a few living grasses and arable weeds were observed close to the pit, but there was ample evidence of tussocky grass rooted clods, indicating high moisture conditions (vlei) during the wet season. (3) The land had been cleared of its trees and grasses during 1991 to accomodate the ICRAF Trial Block, and ploughed. Agroforestry shrubs have not yet been planted in this lower portion of the Block. (4) Occasional, broad, round termite mounds occur further upslope of

Classification

WRB 2006

Haplic- Gleysol (Epidystric Arenic)

40-165 cm	albic horizon
-	reducing conditions
-	gleyic colour pattern

40-165 cm	albic horizon
-	reducing conditions
-	gleyic colour pattern

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Albi-Dystric Gleysol

Dystric Gleysol

0-40 cm	ochric A horizon
40-165 cm	albic E horizon
-	gleyic

0-40 cm	ochric A horizon
40-165 cm	albic E horizon
-	hydromorphic

Land use

Major crops	crops (unspecified)
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	agro-forestry
Remarks on Land Use / Vegetation	VEGETATION: wooded grassland with medium-sized deciduous and semi-deciduous trees and shrubs and annual and perennial grasses are a mixture of species. Brachystegia and Julbernardia spec. no longer dominated the tree/shrub mix whilst Terminalia sericea trees and shrubs are more evident. Tussocky grass and rooted clods indicate high moisture conditions (vlei) during the wet season. LAND USE: Land has been cleared for agroforestry trials.
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)	semi-deciduous woodland

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
0-23	1	9.0	27.4	24.2	20.2	6.6	87.4	5.6	2.6	8.2	4.4
23-40	1	8.8	26.8	23.5	19.1	9.5	87.7	5.0	3.7	8.7	3.7
40-59	1	10.7	27.5	23.0	18.9	6.7	86.8	5.7	3.7	9.4	3.7
59-77	1	8.1	25.1	24.2	19.6	10.2	87.2	3.8	4.7	8.5	4.3
77-99	6	13.7	23.5	20.1	18.1	9.1	84.5	6.5	5.4	11.9	3.5
125-140	8	13.4	26.5	22.4	12.4	8.5	83.2	8.9	4.1	13	3.8
140-165	6	24.0	30.2	19.0	10.6	5.5	89.3	0.7	7.9	8.6	2.2

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-23	-	-	-	2.3	4.4
23-40	-	-	-	1.9	3.7
40-59	-	-	-	1.0	3.7
59-77	-	-	-	2.3	4.3
77-99	-	-	-	2.8	3.5
125-140	-	-	-	3.2	3.8
140-165	-	-	-	1.8	2.2

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
0-23	4.6	4.0	0.04	-	0.50	0.02	25	0.7	0.4	0.2	0.0	0.1	0.5	0.8
23-40	4.7	4.1	0.03	-	0.28	0.02	14	0.5	0.2	0.0	0.0	0.0	0.5	0.5
40-59	4.6	4.2	0.04	-	0.19	0.01	19	0.4	0.2	0.0	0.0	0.0	0.0	-
59-77	4.5	4.3	0.08	-	0.27	0.01	27	0.3	0.2	0.2	0.0	0.1	0.5	0.8
77-99	4.8	4.4	0.04	-	0.07	0.01	7	0.1	0.0	0.4	0.0	0.1	0.4	0.9
125-140	5.2	4.5	0.02	-	0.01	-	-	0.1	0.0	0.2	0.3	0.0	0.1	0.6
140-165	5.4	4.6	0.02	-	0.03	-	-	0.1	0.0	0.2	0.3	0.0	0.4	0.9

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 %
0-23	35	2.3	52	1.8	-	17	22
23-40	42	1.2	32	1.0	-	17	42
40-59	-	1.0	27	0.7	-	20	0
59-77	89	0.9	21	0.9	-	22	56
77-99	129	0.7	20	0.2	-	0	57
125-140	60	1.0	26	-	-	0	10
140-165	129	0.7	32	0.1	-	0	57

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-23	-	weak	-	-	-	-	strong to very strong	very weak to weak	-	weak	-	-
23-40	-	weak	-	-	-	-	very strong	weak	-	weak	-	-
40-59	-	weak	-	-	-	-	very strong	weak	-	weak	-	-
59-77	-	weak	-	-	-	-	very strong	weak	-	weak	-	-
77-99	-	weak	-	-	-	-	very strong	weak to medium	-	weak	-	-
125-140	-	very weak to weak	-	-	-	-	very strong	weak to medium	-	very weak to weak	-	-
140-165	-	very weak to weak	-	-	-	-	very strong	weak to medium	-	very weak to weak	-	-

Profile description

Ah1 0-23 cm	dark grey (10YR 4/1, dry) black (10YR 2/1, moist)coarse sand, highly decomposed herbaceous fragments,weakly coherent coarse single grain,loose non sticky non plastic,no cutans,few very fine interstitial random pores moderately porous (40-60 vol%),many very fine and common medium roots,no inclusions,no fragments,very frequent termite channels,non calcareous,clear wavy boundary to,
Ah2 23-40 cm	greyish brown (10YR 5/2, dry) very dark brown (10YR 2/2, moist)coarse sand, highly decomposed herbaceous fragments,weakly coherent porous massive,soft non sticky non plastic,no cutans,common very fine interstitial random pores highly porous (>60 vol%),common very fine and common medium roots,no inclusions,no fragments,very frequent termite channels,non calcareous,clear wavy boundary to,
C1 40-59 cm	light grey (10YR 7/2, dry) brown (10YR 5/3, moist)coarse sand,weakly coherent porous massive,slightly hard non sticky non plastic,no cutans,many very fine interstitial random pores highly porous (>60 vol%),few very fine roots,no inclusions,no fragments,few termite channels,non calcareous,clear smooth boundary to,
C2 59-77 cm	light grey (10YR 7/2, dry) brown (10YR 5/3, moist)coarse sand,weakly coherent porous massive,slightly hard non sticky non plastic,no cutans,many very fine interstitial random pores highly porous (>60 vol%),no inclusions,no fragments,few termite channels,non calcareous,gradual smooth boundary to,
C3 77-99 cm	white (10YR 8/2, dry) light grey (10YR 7/2, moist)coarse sand,weakly coherent porous massive,slightly hard non sticky non plastic,no cutans,many very fine interstitial random pores highly porous (>60 vol%),no inclusions,no fragments,few termite channels,non calcareous,abrupt wavy boundary to,
Coc 99-125 cm	white (10YR 8/2, dry) light grey (10YR 7/2, moist)coarse sand gravelly,weakly coherent porous massive,non sticky non plastic,common (5-15%) coarse prominent clear mottles 10YR5/8 (yellowish brown),no cutans,many medium interstitial random pores moderately porous (40-60 vol%),very frequent small and medium spherical hard ferruginous concretions,many fine gravel weathered quartz and many coarse gravel weathered quartz fragments,no,non calcareous,clear wavy boundary to,
Cg1 125-140 cm	white (10YR 8/1, dry) light grey (10YR 7/2, moist)coarse sand slightly gravelly,single grain,loose sticky non plastic,few (2-5%) coarse prominent clear mottles 10YR5/8 (yellowish brown)and few (2-5%) coarse prominent clear mottles,no cutans,many medium interstitial random pores moderately porous (40-60 vol%),very few small spherical hard ferruginous concretions,many fine gravel weathered quartz fragments,no,non calcareous,clear smooth boundary to,
Cg2 140-165 cm	white (10YR 8/1, dry) light grey (10YR 7/2, moist)coarse sand slightly gravelly,single grain,loose non sticky non plastic,few (2-5%) coarse prominent clear mottles 10YR5/8 (yellowish brown) and few (2-5%) coarse prominent clear mottles,no cutans,many medium interstitial random pores highly porous (>60 vol%),no inclusions,few fine gravel weathered quartz fragments,no,non calcareous,abrupt smooth boundary to,
Cg3 165-230 cm	white (10YR 8/1, dry) light grey (10YR 7/2, moist)coarse sandy loam slightly gravelly,single grain,firm sticky plastic,few (2-5%) coarse prominent clear mottles 10YR5/8 (yellowish brown) and few (25%) coarse prominent clear mottles,no cutans,many medium interstitial random pores moderately porous (40-60 vol%),no inclusions,frequent fine gravel weathered quartz fragments,non calcareous,

Depth1	230cm
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	granodiorite
Soil Depth	230cm
Texture of parent material	sandy
Weathering Resistance	high
General characterization of the status of weathering of solid rock	slightly

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

Altitude	1220m
Physiographic Unit	vlei margin
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	north
Form of the slope surrounding the site	concave
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	125cm
Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
Dry From - To	0-125cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	apparent
Moist From - To	125-230cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	slow
Upper limit of a slow permeable or stagnating layer in the profile	99cm

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	250
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)	little 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 13: Gleysol

Characteristics

Reference soil ZW013: Gleysols

Classification