Reference soil Sri Lanka 04: Acrisol

LK004

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 LK004: Acrisol

CLASSIFICATION: 1. Classification by collectors: Udult or Humult. 2. FAO-UNESCO: Nitosol (Nitisol 1988) or Acrisol depending on clay distribution within profile; probably Acrisol because the horizon >104 cm is named B? indicating a lower clay content ( probably more than 20% less than maximum). 3. USDA: Difference between Udult and Humult depends on organic matter content; between Tropudult and Paleudult see point 2. FAO-UNESCO: Humic Nitisol or Humic Acrisol USDA: Tropudult or Sombrihumult (sombric horizon), Paleudult PARENT MATERIAL: Highland series; hard dark basic rocks. GEOLOGICAL FORMATION: Metamorphic rocks of precambrian age. MINERALOGY: Quartz. Watertable: Highest >6 m. Surface drainage: Dendritic, medium textured. Vegetation type: Tropical mountain (small extent of left natural vegetation). Land use: Tea in adjoining crest. Human influence: Burning. Soil fauna: Worm casts. Additional notes on profile description: Ah: Few coarse roots. Bth: Clay/humus and clay/iron cutans. Climate data: Relative humidity = maximal relative humidity below = minimal relative humidity

Classification

WRB 2014

Acrisol

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
0-7	-	6	7.3	6.5	6.9	2.7	29.4	3.4	13.7	17.1	53.5
7-18	-	7.5	9.2	7.1	7	3	33.8	3.9	9.5	13.4	52.8
18-45	-	4.2	7.4	7.1	7.1	2.7	28.5	1.7	11.9	13.6	57.9
45-85	-	7.1	7.2	6.3	6.3	2.6	29.5	2	10.3	12.3	58.2
85-104	-	6.4	6.1	5.1	5.9	2.7	26.2	2.2	11.9	14.1	59.8
104-	-	4.9	5.6	5.1	6.5	3.7	25.8	4.4	20.2	24.6	49.6

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
1-18	1.02	-	-	-	-
0-7	-	-	-	-	53.5
7-18	-	-	-	-	52.8
18-45	1.22	-	-	-	57.9
45-85	1.2	-	-	-	58.2
102-107	1.35	-	-	-	-
85-104	-	-	-	-	59.8
104-	-	-	-	-	49.6

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
1-18	1.02	57	55	48.2	40.5	37.3	34.9	20.7	20.1
18-45	1.22	43.9	40.6	31.3	25.5	23.2	21.1	24.1	24
45-85	1.2	62.3	57.4	52.9	48.6	47.1	45.8	24.4	24.1
102-107	1.35	49.6	48.9	46.5	43.9	42.6	41.4	31.5	30.9

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
0-7	4.5	3.9	0.6	-	10.27	0.76	14	-	-	3.4	1.7	0	0.4	5.5
7-18	4.4	3.9	0.14	-	2.94	0.29	10	-	-	1.0	0.1	0	0.1	1.2
18-45	4.7	4.0	0.08	-	1.69	0.17	10	-	-	0.4	0.1	0	0.1	0.6
45-85	4.9	4.2	0.08	-	1.13	0.11	10	-	-	1.0	0.1	0	0.1	1.2
85-104	4.9	4.3	0.02	-	0.97	0.11	9	-	-	0.4	0.1	0	0.1	0.6
104-	5.5	5.1	0.02	-	0.23	0.04	6	-	-	0.6	0.0	0	0.1	0.7

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 %
0-7	13	43.5	81	35.9	-	-	-
7-18	6	21.8	41	10.3	-	-	-
18-45	4	16.9	29	5.9	-	-	-
45-85	8	14.9	26	4	-	-	-
85-104	4	14.7	25	3.4	-	-	-
104-	9	8.2	17	0.8	-	-	-

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
0-7	-	-	-	0.45	0.03	5.08	1.49	3.13	1.96	-	0.49
7-18	-	-	-	0.41	0.04	5.71	1.55	3.48	2.15	-	0.61
18-45	-	-	-	0.39	0.01	6.38	1.78	4.43	3.86	-	0.51
45-85	-	-	-	0.38	0.01	6.55	1.78	4.23	3.94	-	0.29
85-104	-	-	-	0.32	0.02	8.32	1.92	4.78	4.08	-	0.2
104-	-	-	-	0.15	0.03	10.42	1.59	0.97	0.71	-	0.08

Elemental composition of the soil

Depth (cm)	Al2O3 % w/w	CaO % w/w	Fe2O3 % w/w	K2O % w/w	MgO % w/w	Na2O % w/w	SiO2 % w/w	TiO2 % w/w
0-7	17.4	0.23	10.7	0.50	0.48	-	40.5	2.13
7-18	19.3	0.04	12.5	0.51	0.43	-	49.0	2.37
18-45	22.0	0.05	13.8	0.56	0.5	-	46.5	2.49
45-85	22.6	0.01	14.1	0.59	0.48	-	46.0	2.3
85-104	24.9	0.01	15.4	0.63	0.43	-	43.2	2.26
104-	28.6	0.01	18.9	0.28	0.14	-	34.4	2.66

Depth (cm)	Al2O3/Fe2O3 mol/mol	LOI % w/w	MnO2 % w/w	P2O5 % w/w	SiO2 / Al2O3 mol/mol	SiO2/Fe2O3 mol/mol	SiO2 / R mol/mol
0-7	2.6	27.9	0.03	0.11	4	10.1	2.8
7-18	2.4	15.9	0.03	0.08	4.3	10.4	3.0
18-45	2.5	14.4	0.04	0.08	3.6	9.0	2.6
45-85	2.5	13.6	0.04	0.10	3.5	8.7	2.5
85-104	2.5	13.4	0.04	0.13	2.9	7.5	2.1
104-	2.4	15.1	0.03	0.16	2	4.8	1.4

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-7	-	-	strong	weak to medium	-	-	strong	-	-	-	weak to medium	very weak to weak
7-18	-	-	strong	weak to medium	-	-	strong	-	-	-	weak to medium	very weak
18-45	-	-	strong	weak to medium	-	-	medium to strong	-	-	-	weak to medium	-
45-85	-	-	strong	weak to medium	-	-	medium to strong	-	-	-	weak to medium	-
85-104	-	-	strong	weak to medium	-	-	strong	-	-	-	weak to medium	-
104-	-	-	strong	weak to medium	-	-	strong	-	-	-	weak	-

Profile description

Ah 0-7 cm	very dark greyish brown (10YR 3/2, moist)moderate fine crumb,friable non sticky non plastic,many fine continuous exped and inped interstitial pores,clear smooth boundary to,
E 7-18 cm	yellowish brown (10YR 5/6, moist)clay loam,weak coarse subangular blocky,friable slightly sticky slightly plastic,no cutans,few fine continuous inped tubular pores and many continuous inped tubular pores,no inclusions,very few fine gravel fresh Quartz very few medium gravel fresh Quartz fragments,gradual smooth boundary to,
EB 18-45 cm	(10YR 4.5/6, moist)clay loam,weak coarse subangular blocky,friable slightly sticky slightly plastic,patchy thin clay and sesquioxide cutans,many micro continuous exped and inped interstitial pores and many continuous exped and inped tubular pores,no inclusions,very few fine gravel fresh Quartz very few medium gravel fresh Quartz fragments,clear smooth boundary to,
Bth 45-85 cm	dark yellowish brown (10YR 4/6, moist)clay loam,weak coarse subangular blocky,friable slightly sticky slightly plastic,broken moderately thick unspecified cutans,many very fine continuous exped and inped interstitial pores and few continuous exped and inped tubular pores,no inclusions,very few fine gravel fresh Quartz very few medium gravel fresh Quartz fragments,clear smooth boundary to,
Bt 85-104 cm	strong brown (7.5YR 5/8, moist)clay loam,weak medium subangular blocky,friable slightly sticky slightly plastic,broken moderately thick clay and sesquioxide cutans,many very fine fine continuous exped and inped interstitial pores and common continuous exped and inped tubular pores,no inclusions,very frequent medium gravel fresh Quartz very frequent coarse gravel fresh Quartz fragments,clear smooth boundary to,
B 104- cm	red (2.5YR 5/8, moist)clay loam,moderate coarse subangular blocky,friable slightly sticky slightly plastic,broken moderately thick clay and sesquioxide cutans,common very fine fine continuous exped and inped interstitial pores and common fine continuous exped and inped tubular pores,no inclusions,frequent fine gravel weathered Quartz, gneiss frequent medium gravel weathered Quartz, gneiss fragments,

Kind 1 (parent material) ; Parker (eds), 1984	metamorphic rock
Mode of accumulation or deposition of parent material	solid rock
Texture of parent material (second entry)	clayey

Major crops	tea
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	high level mixed farming
Remarks on Land Use / Vegetation	See remarks
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	crop rotation scheme not relevant

Altitude	1500m
Physiographic Unit	upper slope of a hill
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.	hill
Slope	2%
Slope Aspect	south
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	steeply dissected

Drainage class ; FAO (2006) - Guidelines for soil description	somewhat excessive
Flooding frequency (FAO, 1986)	never
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-104cm
Estimated run off (class)	medium

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
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	level
Microrelief pattern	none
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

You are here

Reference soil Sri Lanka 04: Acrisol

Characteristics

Reference soil LK004: Acrisol

Classification