Reference soil Brazil 23: Acrisol

BR023

Acrisols occur dominantly in the wetter parts of the tropics and subtropics and the warm temperate regions in relatively young landscapes.

Characteristics

Soils having an argic horizon (a subsurface horizon with 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 100 cm from the soil surface, or within 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 less than 50 percent in the major part between 25 and 100 cm from the soil surface

Distribution of Acrisols (rough estimation supplied by soilgrids)

Reference soil BR023: Acrisols

Moderately deep, imperfectly drained clay derived from conglomerate with a strongly mottled subsoil. The Bg1 and Bg2 horizons are multicoloured, no real matrix colour can be given. The CB horizon consisting of highly weathered conglomerate shows different texture types from sandy to clayey materials. Climate: registration period precipitation 1931-1970 *) Geomorphology: a characteristic 'demi-orange' relief ('meia laranja'). Steep hills with flat valley floor. Additional information in: thesis I.A.Gomes July 1985 Piracicaba S.Paula/Brasil. Slides no 9855-9862 *) Brazilian classification: Podzolico Vermelho-Amearelo alico Tb.

Classification

WRB 2006

WRB 1998

Haplic- Acrisol (Ferric Alumic Clayic)

Alumi-Ferric- Acrisol (Chromic)

28-88 cm	ferric horizon
8-56 cm	argic horizon

0-28 cm	ochric horizon
28-88 cm	ferric horizon
8-56 cm	argic horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Chromi-Ferric Acrisol

Ferric Acrisol

0-28 cm	ochric A horizon
8-56 cm	argic B horizon
- cm	argic B horizon
- cm	ochric A horizon
-	ferric

0-28 cm	ochric A horizon
8-56 cm	argillic B horizon
-	ferric

Local classification:	Podzólico Vermelho-Amarelo álico Tb

Other classification

USDA-NRCS (1999)	Oxyaquic Hapludult
USDA-SCS (1975)	Oxyaquic Tropudult udic clayey mixed 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
0-8	10	6.8	10.6	12.4	19.5	11.3	60.6	10.0	7.8	17.8	21.6
8-28	-	3.4	6.1	5.3	7.5	5.3	27.6	6.2	9.4	15.6	56.8
28-56	-	4.5	7.0	4.9	5.5	4.2	26.1	5.9	16.8	22.7	51.3
56-88	-	3.5	8.3	7.6	10.0	6.5	35.9	9.1	18.1	27.2	37.0
88-150	-	5.9	9.1	7.4	10.4	7.1	39.9	8.1	26.0	34.1	26.0
110-130	-	4.3	14.5	16.7	17.6	9.8	62.9	11.3	13.1	24.4	12.7
160-250	-	5.6	9.9	8.4	12.4	8.0	44.3	8.5	26.5	35.0	20.7

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-8	-	-	-	14.0	21.6
3-8	1.342	-	-	-	-
8-28	-	-	-	35.5	56.8
25-30	1.121	-	-	-	-
28-56	-	98	-	31.0	51.3
80-85	1.360	-	-	-	-
56-88	-	132	-	16.0	37.0
115-120	1.350	-	-	-	-
88-150	-	-	-	9.6	26.0
110-130	-	-	-	7.6	12.7
160-250	-	-	-	9.9	20.7

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
3-8	1.342	37.3	31.3	26.6	23.3	20.8	19.5	17.1	16.9
25-30	1.121	57.6	54.5	50.7	48.5	46.8	45.3	33.9	33.8
80-85	1.360	50.4	48.7	47.4	46.1	44.6	43.2	32.3	31.8
115-120	1.350	49.6	47.4	45.8	43.9	41.2	38.6	13.5	13.5

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
0-8	5.0	4.0	0.09	-	1.74	0.10	17	1.2	1.1	0.8	1.2	0.4	0.0	2.4
8-28	5.0	3.7	0.03	-	1.15	0.11	10	7.5	7.8	0.4	1.6	0.4	0.1	2.5
28-56	5.0	3.8	0.03	-	0.59	0.07	8	10.1	10.5	0.2	1.5	0.2	0.1	2.0
56-88	5.1	3.8	0.03	-	0.27	-	-	7	7.3	0.0	1.0	0.1	0.0	1.1
88-150	5.0	3.7	0.03	-	0.14	-	-	10.7	10.5	0.0	1.3	0.1	0.2	1.6
110-130	5.0	4.0	0.02	-	0.06	-	-	3.0	2.9	0.0	0.4	0.0	0.1	0.5
160-250	5.0	3.6	0.03	-	0.07	-	-	11.7	11.9	0.0	1.8	0.2	0.1	2.1

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 %
0-8	13	18.1	84	6.1	-	6	0
8-28	20	12.7	22	4.0	-	61	1
28-56	17	12.0	23	2.1	-	88	1
56-88	11	10.0	27	0.9	-	73	0
88-150	12	13.6	52	0.5	-	77	1
110-130	18	2.8	22	0.2	-	104	4
160-250	14	14.7	71	0.2	-	81	1

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
0-8	-	15	-	0.10	0.00	0.80	0.10	-	-	-	0.20
8-28	-	34	-	0.20	0.00	2.00	0.30	-	-	-	0.30
28-56	-	40	-	0.20	0.00	2.00	0.30	-	-	-	0.30
56-88	-	-	-	0.20	0.00	1.40	0.20	-	-	-	0.10
88-150	-	33	-	0.20	0.00	1.30	0.20	-	-	-	0.10
110-130	-	-	-	0.10	0.00	0.40	0.10	-	-	-	0.00
160-250	-	31	-	0.10	0.00	0.60	0.10	-	-	-	0.00

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-8	-	-	-	weak	-	-	very strong	medium to strong	weak	-	medium to strong	-
8-28	-	-	-	weak	-	-	very strong	medium to strong	weak	-	medium to strong	-
28-56	-	-	-	very weak	-	-	very strong	weak	weak	-	weak	-
56-88	-	-	-	very weak	-	-	very strong	very weak	weak	-	weak	-
88-150	-	-	-	very weak	-	-	strong	very weak	weak	-	weak	-
110-130	-	-	-	very weak	-	-	strong	very weak	weak	-	weak	-
160-250	-	-	-	very weak	-	-	strong	very weak	weak	-	medium to strong	-

Profile description

Ah 0-8 cm	(dark) brown (10YR 4/3, moist)sandy clay loam,weak fine and medium subangular blocky,firm sticky very plastic,common very fine pores and few pores,clear smooth boundary to,
8-28 cm	brown (10YR 5/3, moist)clay,weak to moderate fine and medium subangular blocky,firm sticky very plastic,common very fine pores and few pores,clear smooth boundary to,
Bg1 28-56 cm	light brown (7.5YR 6/4, moist)clay,moderate fine and medium subangular blocky,firm sticky very plastic,many coarse prominent mottles (2.5 YR 3/6),continuous moderately thick pressure on pedfaces cutans,few very fine pores and few inped tubular random pores,gradual smooth boundary to,
Bg2 56-88 cm	light yellowish brown (10YR 6/4, moist)clay,moderate fine and medium subangular blocky,firm sticky very plastic,many coarse prominent mottles (2.5 YR 3/6),broken moderately thick pressure on pedfaces cutans,few very fine pores and few inped tubular random pores,clear wavy boundary to,
CB 88-150 cm	reddish yellow (7.5YR 7/6, moist)loamy sand,weakly coherent porous massive,friable non sticky non plastic,frequent coarse gravel strongly weathered conglomerate fragments,

Kind 1 (parent material) ; Parker (eds), 1984	conglomerate
Mode of accumulation or deposition of parent material	colluvial
Remarks on Parent Materials	Tertiary arkosic conglomerate
Soil Depth	150cm
Texture of parent material	sandy clay
Weathering Resistance	moderate
General characterization of the status of weathering of solid rock	highly

Intensity of the soil erosion type	moderate
Soil erosion type	sheet

Major crops	sugar cane
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	medium level arable farming
Remarks on Land Use / Vegetation	VEGETATION: Floresta tropical subperenifólia LANDUSE:
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	monoculture

Altitude	80m
Physiographic Unit	typical 'demi-orange' relief ('meia laranja'); steep hills with flat valley floor
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.	hill
Slope	40%
Slope Aspect	west
Form of the slope surrounding the site	convex
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	rolling

Drainage class ; FAO (2006) - Guidelines for soil description	moderately well
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-150cm
Estimated permeability (class) of least permeable part of the profile	moderate
Estimated run off (class)	rapid

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
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 Brazil 23: Acrisol

Characteristics

Reference soil BR023: Acrisols

Classification