Reference soil Colombia 08: Acrisol

CO008

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 CO008: Acrisols

PHYSIOGRAPHY: Local relief: 10 - 15 m. CLIMATE: Available data of the Araracuara area are incomplete. The rainfall is estimated between 3000-3500 mm/year (closer to 3000 mm) with a minumum in January between 150-200 mm (closer to 150 mm). A maximum is recorded in July between 200-250 mm (closer to 250 mm). The evaporation is estimated to be about half of the precipitation, e.g. about 1600 mm/year. The relative humidity is more than 75% with a maximum in January and February. ADDITIONAL NOTES ON PROFILE DESCRIPTION: Ah - also many coarse roots; AB - also common coarse roots; - coprogenic elements: fecal pellets. Charcoal from 8 to 75 cm; a rootmat is expressed from 0-8 cm; all very coarse roots are confined to the top 21 cm; Land use: hunting and food gathering;

Classification

WRB 2006

WRB 1998

Cutanic- Acrisol (Alumic Humic Profondic)

Profondi-Humic- Acrisol (Alumic Chromic)

21-150 cm

argic horizon

0-21 cm	ochric horizon
21-150 cm	argic horizon
-	strongly humic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Humi-Haplic Acrisol

Ferric Acrisol

0-21 cm	ochric A horizon
21-150 cm	argic B horizon
- cm	argic B horizon
- cm	ochric A horizon
-	strongly humic

0-21 cm	ochric A horizon
21-150 cm	argillic B horizon
-	ferric

Other classification

USDA-NRCS (1999)	Ustic Kanhaplohumult
USDA-SCS (1975)	Ustic Paleudult udic clayey kaolinitic isohyperthermic

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	-	0.7	1.7	7.9	21.1	6.2	37.6	5.5	10.1	15.6	46.7
8-21	-	0.2	0.7	4.2	17.3	6.3	28.7	6.9	11.1	18.0	53.2
21-50	-	0.3	0.6	3.7	13.5	5.4	23.5	4.8	11.5	16.3	60.2
50-75	-	0.1	0.7	2.8	12.1	4.8	20.5	5.0	10.6	15.6	63.9
75-100	-	0.2	0.5	2.5	11.5	4.3	19.0	3.0	12.8	15.8	65.3
100-150	-	0.6	0.5	2.5	10.2	4.0	17.8	6.9	12.8	19.7	62.5

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
20-28	1.010	-	-	-	-
0-8	-	-	-	10.7	46.7
60-68	1.100	-	-	-	-
8-21	-	-	-	10.4	53.2
105-113	1.150	-	-	-	-
21-50	-	-	-	0.2	60.2
50-75	-	-	-	0.4	63.9
75-100	-	-	-	0.0	65.3
100-150	-	-	-	0.0	62.5

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
20-28	1.010	59.8	54.6	50.2	47.3	45.7	44.6	38.2	36.0
60-68	1.100	56.6	55.6	53.4	50.9	49.8	48.7	44.8	42.7
105-113	1.150	58.0	57.3	55.0	52.9	51.8	50.6	47.3	45.5

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	3.7	3.6	0.21	-	6.46	0.40	16	8.4	6.7	0.0	0.0	0.0	0.1	0.1
8-21	4.2	3.9	0.13	-	1.56	0.14	11	4.5	3.6	0.4	0.0	0.0	0.0	0.4
21-50	4.5	3.9	0.04	-	0.89	0.09	10	4.2	3.6	0.0	0.0	0.0	0.3	0.3
50-75	4.9	3.9	0.02	-	0.63	0.03	21	3.5	3.1	0.0	0.1	0.1	0.0	0.2
75-100	4.9	3.9	0.02	-	0.47	-	-	3.7	3.1	0.0	0.0	0.0	0.0	0.0
100-150	5.0	3.9	0.01	-	0.36	-	-	4.8	4.1	0.0	0.0	0.1	0.0	0.1

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	0	31.0	66	22.6	-	22	0
8-21	3	14.4	27	5.5	-	25	0
21-50	2	13.3	22	3.1	-	27	2
50-75	2	10.8	17	2.2	-	29	0
75-100	0	9.9	15	1.6	-	31	0
100-150	1	13.2	21	1.3	-	31	0

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	-	-	-	0.37	0.01	2.69	0.95	-	-	-	0.29
8-21	-	-	-	0.24	0.03	3.14	0.90	-	-	-	0.27
21-50	-	-	-	0.31	0.04	3.61	0.84	-	-	-	0.09
50-75	-	-	-	0.17	0.03	3.76	0.86	-	-	-	0.05
75-100	-	-	-	0.23	0.06	4.07	0.81	-	-	-	0.04
100-150	-	-	-	0.20	0.03	4.88	0.72	-	-	-	0.04

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-8	-	medium to strong	-	-	-	-	very strong	-	-	medium to strong	-	weak
8-21	-	-	-	-	-	-	very strong	-	-	weak	-	medium to strong
21-50	-	-	-	-	-	-	very strong	-	-	very weak	-	medium to strong
50-75	-	-	-	-	-	-	very strong	-	-	very weak	-	weak
75-100	-	-	-	-	-	-	very strong	-	-	very weak	-	weak
100-150	-	-	-	-	-	-	very strong	-	-	very weak	-	weak

Profile description

Ah 0-8 cm	dark brown (7.5YR 3/2, moist)sandy clay loam,weak fine subangular blocky,soft friable slightly sticky slightly plastic,many fine to coarse tubular pores,gradual smooth boundary to,
8-21 cm	(dark) brown (7.5YR 4/4, moist)sandy clay loam,weak fine subangular blocky,slightly hard friable sticky plastic,common many fine to coarse tubular pores,charcoal inclusions,few fine gravel charcoal fragments,frequent coprogenic elements,gradual smooth boundary to,
Bt1 21-50 cm	reddish brown (5YR 4/4, moist)clay,moderate fine subangular blocky,friable sticky plastic,patchy moderately thick cutans,common fine tubular pores and common pores,charcoal inclusions,few charcoal fragments,frequent pedotubules,gradual smooth boundary to,
Bt2 50-75 cm	(5YR 4/8, moist)clay,moderate fine angular blocky,friable sticky very plastic,broken moderately thick cutans,few fine tubular pores and common pores,charcoal inclusions,charcoal,few charcoal fragments,frequent pedotubules,gradual smooth boundary to,
Bto 75-100 cm	red (2.5YR 4/6, moist)clay,weak to moderate fine angular blocky,friable sticky very plastic,broken moderately thick cutans,few few fine medium tubular pores and common common tubular pores,few quartz grain fragments,few pedotubules,diffuse smooth boundary to,
Bo 100-150 cm	red (2.5YR 4/8, moist)clay,weak to moderate fine angular blocky,friable sticky very plastic,broken moderately thick cutans,few few fine medium tubular pores and common common tubular pores,few pedotubules,

Mode of accumulation or deposition of parent material	unconsolidated, unspecified
Remarks on Parent Materials	Plio-Pleistocene sediment
Texture of parent material	clayey

Land use or vegetation in the immediate vicinity of the site	(semi-)natural vegetation
Remarks on Land Use / Vegetation	VEGETATION: Palm trees LANDUSE: Hunting and food gathering
Status of vegetation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	primary
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	evergreen forest

Altitude	230m
Physiographic Unit	denud.sedimentary upland plain
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.	plain
Slope	3%
Slope Aspect	north-east
Form of the slope surrounding the site	straight
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	undulating

Drainage class ; FAO (2006) - Guidelines for soil description	well
Moist From - To	0-150cm

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline

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Reference soil Colombia 08: Acrisol

Characteristics

Reference soil CO008: Acrisols

Classification