Reference soil Brazil 17: Solonetz

BR017

Solonetzes occur where a sodium source supplies the clay-rich subsoil with exchangeable Na, causing peptization of clay and organic substances and deterioration of the topsoil.

Characteristics

Soils having a natric horizon (a subsurface horizon with distinct higher clay content than the overlying horizon and more than 15% exchangeable sodium) within 100 cm from the soil surface.

Distribution of Solonetz (rough estimation supplied by soilgrids)

Reference soil BR017: Solonetz

Brief description: Moderately deep, imperfectly drained, sandy clay derived from gneiss; abruptly overlain by a sandy loam topsoil (duplex profile). A banded gneiss structure is visible in the C-horizon. The E2-horizon is not always present, and the thickness varies between 0-15 cm. Parent material: Pre-cambrium biotite(?) gneiss. Koppen climate on the limit between As and BSh. USDA moisture regime between ustic to aridic. Natural vegetation:"Caatinga hipoxerofila", for spp. listing see field archive. Additional information: sSee boletim tecnico no 35 (ISRIC-library) Slides no 9806-9816.

Classification

WRB 2006

WRB 1998

Stagnic- Solonetz (Albic Abruptic Magnesic)

Stagni-Magnesic- Solonetz (Albic)

20-30 cm	albic horizon
30-67 cm	natric horizon
-	abrupt textural change
-	reducing conditions

0-6 cm	ochric horizon
20-30 cm	albic horizon
30-67 cm	natric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Albi-Haplic Solonetz

Solodic Planosol

0-6 cm	ochric A horizon
20-30 cm	albic E horizon
30-67 cm	natric B horizon
- cm	natric B horizon
-	abrupt textural change

0-6 cm	ochric A horizon
20-30 cm	albic E horizon
30-67 cm	natric B horizon
-	abrupt textural change

Local classification:	Planossolo solódico

Other classification

USDA-NRCS (1999)	Typic Natrustalf
USDA-SCS (1975)	Typic Natrustalf ustic coarse-loamy over clayey isohyperthermic

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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
0-6	4	3.9	10.8	17.4	30.3	12.2	74.6	7.4	8.1	15.5	9.9
6-20	7	5.1	11.5	16.9	30.2	12.3	76.0	8.3	6.3	14.6	9.4
20-30	64	8.4	12.8	17.0	24.1	10.5	72.8	8.2	7.8	16.0	11.1
30-67	8	5.8	10.0	9.6	13.5	6.3	45.2	6.2	8.0	14.2	40.5
67-90	34	6.2	14.0	25.2	30.8	10.8	87.0	3.1	3.6	6.7	6.4

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-6	-	-	-	4.5	9.9
5-10	1.492	-	-	-	-
6-20	-	-	-	5.8	9.4
20-30	-	-	-	6.6	11.1
30-67	1.644	-	-	37.5	40.5
67-90	-	-	-	6.4	6.4

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
5-10	1.492	42.6	38.7	32.7	21.2	16.0	12.9	8.3	7.5
30-67	1.644	65.3	64.4	62.3	57.3	52.5	47.9	29.6	26.5

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
0-6	5.0	4.4	0.30	-	1.49	0.17	9	0.1	0	3.6	1.5	0.8	0.1	6.0
6-20	5.7	4.6	0.09	-	0.74	0.04	18	0	0	2.8	1.0	0.3	0.0	4.1
20-30	6.0	4.4	0.11	-	0.42	0.05	8	0	0	2.2	1.8	0.2	0.4	4.6
30-67	7.9	5.3	0.43	3.2	0.23	-	-	-	-	2.7	11.4	0.2	9.2	23.5
67-90	9.4	7.3	0.34	2.9	0.05	-	-	-	-	0.8	2.5	0.1	4.1	7.5

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 %
0-6	87	6.9	70	5.2	-	0	1
6-20	93	4.4	47	2.6	-	0	0
20-30	100	4.6	41	1.5	-	0	9
30-67	173	13.6	34	0.8	-	-	68
67-90	129	5.8	91	0.2	-	-	71

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
0-6	-	-	-	0.00	0.10	0.40	0.00	-	-	-	0.10
6-20	-	-	-	0.00	0.00	0.40	0.00	-	-	-	0.10
20-30	-	-	-	0.00	0.00	0.50	0.10	-	-	-	0.10
30-67	-	-	-	0.10	0.10	1.10	0.10	-	-	-	0.10
67-90	-	-	-	0.00	0.00	0.40	0.00	-	-	-	0.00

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-6	-	-	-	weak	-	-	medium to strong	strong	-	-	-	-
6-20	-	-	-	weak	-	-	medium to strong	very strong	-	-	-	-
20-30	-	-	-	weak	-	-	medium to strong	very strong	-	-	weak	-
30-67	-	-	-	weak	-	-	strong	strong	-	-	medium to strong	-
67-90	-	-	-	weak	-	-	medium to strong	medium to strong	-	-	strong	-

Profile description

Ah 0-6 cm	light yellowish brown (10YR 6/4, dry) brown (10YR 5/3, moist)sandy loam,very weak fine subangular blocky,slightly friable non sticky non plastic,common very fine fine pores,clear smooth boundary to,
E1 6-20 cm	very pale brown (10YR 7/3, dry) (10YR 4.5/4, moist)sandy loam,very weak fine subangular blocky,slightly hard friable non sticky non plastic,common very fine fine pores,clear wavy boundary to,
E2 20-30 cm	very pale brown (10YR 7/3, dry) light yellowish brown (10YR 6/4, moist)sandy loam very gravelly,structureless,loose non sticky non plastic,abrupt wavy boundary to,
Bt 30-67 cm	(10YR 4.5/4, moist)clay,moderate medium prismatic parting to strong medium angular blocky,very hard very firm slightly P,broken pressure on pedfaces cutans,few very fine fine pores,clear wavy boundary to,
C 67-90 cm	structurelesshighly firm,very frequent fine gravel weathered gneiss fragments,

Kind 1 (parent material) ; Parker (eds), 1984	basic gneiss
Mode of accumulation or deposition of parent material	residual material
Remarks on Parent Materials	Pre-Cambrium biotite gneiss
Soil Depth	75cm
Texture of parent material	loamy
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

Major crops	fodder crops
Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: Caatinga hipoxerófila LANDUSE: Fodder crop: palma forrageira (Opuntia spp)
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	degraded
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	extremely xeromorphic dwarf shrub

Altitude	240m
Physiographic Unit	weakly dissected planation surface
Physiographic position of the site	middle slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	plain
Slope	4%
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Lower limit of a slow permeable or stagnating layer in the profile	67cm
Drainage class ; FAO (2006) - Guidelines for soil description	imperfect
Dry From - To	0-30cm
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	30-90cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	rapid
Upper limit of a slow permeable or stagnating layer in the profile	30cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Average size of stone	8
Slaking of aggregates by tillage, rainfall or frost (USDA/SCS, 1979)	surface slaked; sorted sand/silt, some clay films
Rock outcrop class (FAO (2006) - Guidelines for soil description)	little rocky
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Shape of stones (on average)	(sub-)rounded
Surface stoniness class (FAO (2006) - Guidelines for soil description)	very few stones

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Reference soil Brazil 17: Solonetz

Characteristics

Reference soil BR017: Solonetz

Classification