Reference soil Zimbabwe 12: Lixisol

ZW012

Lixisols occur dominantly in the drier parts of the tropics and subtropics. Their high base status is partly due to less leaching, partly to admixture from airborne dust from adjacent desert regions.

Characteristics

Soils having an argic horizon (a subsurface horizon with a 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 either: 100 cm from the soil surface, or 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 50 percent or more in the major part between 25 and 100 cm from the soil surface.

Distribution of Lixisols (rough estimation supplied by soilgrids)

Reference soil ZW012: Lixisols

(1) Natural vegetation consists predominantly of medium-sized open woodland trees and shrubs. Brachystegia spiciformis and Julbernardia globiflora trees and shrubs dominate, but there are now more common Terminalia sericea and Parinari curatellifolia trees and shrubs. Vegetation samples were collected from the immediate area outside the fenced Trial Block, and await full identification. (2) Only a few grasses and arable weeds were observed in the immediate vicinity of the pit. (3) The land has been cleared and stumped, to accomodate the ICRAF Agroforestry Trial Block. The upper part of the Block, on the edge of which the pit is situated, was cleared in 1990. The land was ploughed and agroforestry shrubs were planted in December 1990. At the time of planting, each shrub received 10 litres of water every two weeks for a two-month period. Thereafter, no water was applied and the shrubs had to rely on the seasonal rainfall, falling during the months of November to April. During the 1990/91 season, 251 mm

Classification

WRB 2006

Haplic- Lixisol (Albic Epidystric Profondic Arenic)

24-132 cm

albic horizon

24-132 cm

albic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Dystri-Albic Arenosol

Albic Arenosol

0-24 cm	ochric A horizon
24-132 cm	albic E horizon

0-24 cm	ochric A horizon
24-132 cm	albic E horizon

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	LAND USE: Land has been cleared and stumperd, to accomodate agro-forestry trials. Agro-forestry species include Acacia augustisma, Calliandra calliothrus, Flemingia congesta, flemingia macrophila, Gliditsia triacant, Grincidia sepium, Sesbania sesban, leucaena leucocephala and Cajuna cajan. VEGETATION: Natural vegetation consists predominantly of medium sized open woodland trees and shrubs. Brachystegia spiciformis and Julbernardia globiflora trees and shrubs dominate, also Terminalia sericea and Parinari curatellifolia trees and shrubs. Only a few grasses and arable weeds were observed in the immediate vicinity.
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 shrub

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
0-24	1	5.9	20.9	25.2	23.4	10.8	86.2	7.0	2.1	9.1	4.7
24-54	1	8.4	23.3	24.4	23.5	8.4	88	5.1	3.6	8.7	3.4
54-76	1	6.7	21.6	25.3	23.7	11.0	88.3	3.3	4.7	8	3.7
76-104	4	9.3	23.3	24.9	25.4	9.5	92.4	1.3	3.4	4.7	2.9
104-132	3	10.1	22.4	23.3	21.5	10.3	87.6	5.7	4.3	10	2.4
132-182	5	11.6	20.1	19.1	20.1	9.0	79.9	6.4	5.3	11.7	8.4
182-230	10	10.1	21.2	20.3	18.3	10.6	80.5	5.5	6.9	12.4	7.1

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-24	-	-	-	1.8	4.7
24-54	-	-	-	2.8	3.4
54-76	-	-	-	2.3	3.7
76-104	-	-	-	3.4	2.9
104-132	-	-	-	1.5	2.4
132-182	-	-	-	1.4	8.4
182-230	-	-	-	1.4	7.1

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
0-24	5.2	4.5	0.04	-	0.42	0.03	14	0.1	0.0	0.8	0.3	0.1	0.5	1.7
24-54	4.6	4.1	0.03	-	0.06	0.01	6	0.4	0.2	0.0	0.0	0.0	0.0	-
54-76	4.8	4.2	0.02	-	0.06	0.01	6	0.3	0.2	0.0	0.0	0.1	0.5	0.6
76-104	4.8	4.3	0.02	-	0.04	-	-	0.2	0.0	0.0	0.0	0.0	0.0	-
104-132	4.8	4.4	0.05	-	0.01	-	-	0.0	0.0	0.2	0.0	0.0	0.3	0.5
132-182	4.1	4.1	0.26	-	0.03	-	-	0.1	0.0	0.6	0.0	0.1	0.3	1
182-230	4.7	3.9	0.02	-	0.06	0.01	6	0.3	0.2	0.4	0.0	0.0	0.2	0.6

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 %
0-24	89	1.9	40	1.5	-	0	26
24-54	-	0.5	15	0.2	-	40	0
54-76	60	1.0	27	0.2	-	20	50
76-104	-	0.5	17	0.1	-	0	0
104-132	167	0.3	13	0.0	-	0	100
132-182	71	1.4	17	0.1	-	0	21
182-230	50	1.2	17	0.2	-	17	17

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-24	-	very weak to weak	-	-	-	-	medium to strong	very weak to weak	-	weak	-	-
24-54	-	medium to strong	-	-	-	-	medium to strong	very weak to weak	-	strong	-	-
132-182	-	weak	-	-	-	-	very strong	weak to medium	very weak	medium to strong	-	-
182-230	-	weak	-	-	-	-	very strong	weak to medium	very weak	medium to strong	-	-

Profile description

Ah 0-24 cm	light brownish grey (10YR 6/2, dry) dark greyish brown (10YR 4/2, moist)coarse sand, organic (unspecified), highly decomposed,single grain,soft non sticky non plastic,no cutans,few very fine discontinuous exped interstitial random pores highly porous (>60 vol%),medium and coarse roots,no inclusions,no fragments,no,non calcareous,clear wavy boundary to,
C1 24-54 cm	white (10YR 8/2, dry) pale brown (10YR 6/3, moist)coarse sand,single grain,slightly hard non sticky non plastic,no cutans,common very fine discontinuous exped interstitial random pores highly porous (>60 vol%),common medium and coarse roots,no inclusions,no fragments,no,non calcareous,gradual smooth boundary to,
C2 54-76 cm	white (10YR 8/2, dry) pale brown (10YR 6/3, moist)coarse sand,single grain,slightly hard non sticky non plastic,no cutans,common very fine discontinuous exped interstitial random pores highly porous (>60 vol%),few medium and coarse roots,no inclusions,no fragments,no,non calcareous,gradual smooth boundary to,
C3 76-104 cm	white (10YR 8/2, dry) pale brown (10YR 6/3, moist)coarse sand,single grain,slightly hard non sticky non plastic,common (5-15%) fine faint clear 10YR5/8 (yellowish brown) and 7.5YR5/6 (strong brown) mottles,no cutans,common very fine discontinuous exped interstitial random pores moderately porous (40-60 vol%),few medium and coarse roots,no inclusions,no fragments,no,non calcareous,gradual smooth boundary to,
C4 104-132 cm	white (10YR 8/2, dry) pale brown (10YR 6/3, moist)coarse sand,single grain,soft non sticky non plastic,common (5-15%) fine faint clear 10YR5/8 (yellowish brown) and 7.5YR5/6 (strong brown) mottles,no cutans,many fine discontinuous exped interstitial random pores,few fine and medium roots,no inclusions,no fragments,no,non calcareous,clear smooth boundary to,
C5 132-182 cm	white (10YR 8/2, dry) pale brown (10YR 6/3, moist)loamy coarse sand,strongly coherent massive,hard slightly sticky non plastic,common (5-15%) medium prominent sharp mottles 5.0YR4/6 (Invalid Code:) and common (5-15%) coarse prominent sharp mottles 2.5YR4/8 (red),no cutans,many fine discontinuous exped interstitial random pores,few fine and medium roots,no inclusions,no fragments,no,non calcareous,diffuse smooth boundary to,
C6 182-230 cm	white (10YR 8/2, dry) pale brown (10YR 6/3, moist)loamy coarse sand,strongly coherent massive,hard slightly sticky non plastic,common (5-15%) medium prominent sharp mottles 5.0YR4/6 (Invalid Code:) and common (5-15%) coarse prominent sharp 2.5YR4/8 (red) mottles,no cutans,many fine discontinuous exped interstitial random pores moderately porous (40-60 vol%),few fine and medium roots,no inclusions,no fragments,no,non calcareous,

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
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	long interfluve
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.	pediment
Slope	2%
Slope Aspect	west
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	230cm
Drainage class ; FAO (2006) - Guidelines for soil description	excessive
Dry From - To	0-230cm
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	moderate
Estimated run off (class)	slow
Upper limit of a slow permeable or stagnating layer in the profile	132cm

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)	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 12: Lixisol

Characteristics

Reference soil ZW012: Lixisols

Classification