Reference soil Philippines 05: Vertisol

PH005

Vertisols occur dominantly in level landscapes under climates with a pronounced dry season. Vast areas are found in Australia, India, northeastern Africa (Sudan, Ethiopia), southern Latin America and the USA.

Characteristics

Soils having a vertic horizon (a clayey subsurface horizon with polished and grooved ped surfaces ("slickensides") or wedge-shaped or parallelepiped structural aggregates) within 100 cm from the soil surface. They have 30 percent or more clay in all horizons to a depth of 100 cm or more, or to a contrasting layer (lithic or paralithic contact, petrocalcic, petroduric or petrogypsic horizons, sedimentary discontinuity, etc.) between 50 and 100 cm, after the upper 20 cm have been mixed. In addition, Vertisols exhibit wide cracks, which open and close periodically.

Distribution of Vertisols (rough estimation supplied by soilgrids)

Reference soil PH005: Vertisols

A poorly drained dark gray soil (5 Y 4/1) derived from older alluvial deposits with many mottles of different colours (n mottles in Bg3 horizon). Due to irrigated paddy culture, there are paddy dikes as mesorelief; slope gradient 0-2 %. (FAO classification: anthraquic pellic Vertisol)

Classification

WRB 2014

Vertisol

FAO-UNESCO-ISRIC 1974

Pellic Vertisol

Local classification:	Bigaa series

Other classification

USDA-SCS (1975)

Pellustert ustic clayey montmorillonitic 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
0-13	-	0.1	0.2	1.3	11.4	14.1	27.1	18.6	22.4	41	32
13-24	-	0	0.1	0.1	0.5	0.9	1.6	5.9	26.5	32.4	66
24-60	-	0	0.2	1.1	9.4	10.5	21.2	15.5	18.6	34.1	44.7
60-103	-	0	0	0	0.1	0.5	0.6	3.9	25.3	29.2	70.1
103-	-	0	0.2	1.7	7	8.8	17.7	17.4	22.9	40.3	42

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-13	-	-	-	-	32
0-11	0.94	-	-	-	-
13-24	1.166	-	-	-	66
24-60	1.161	-	-	-	44.7
60-103	1.242	-	-	-	70.1
103-	-	-	-	-	42

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
0-11	0.94	63.2	62	61.7	60.6	58.6	56.1	21.8	18.8
13-24	1.166	57.9	56.4	55.8	54.6	53.7	52.4	42.1	35.1
24-60	1.161	59.5	58.2	57.5	56.7	56.2	54.7	43.6	36.5
60-103	1.242	59.9	58.8	58.4	57.6	57	54.8	48.6	41

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
0-13	5.8	4.4	0.16	-	1.36	-	-	-	-	11.7	5.3	0.2	0.2	17.4
13-24	6.8	5.4	0.24	-	0.87	-	-	-	-	33.1	13.1	0.2	0.7	47.1
24-60	7.0	5.5	0.16	-	0.31	-	-	-	-	23.1	11.8	0.3	0.5	35.7
60-103	7.1	5.3	0.21	-	0.57	-	-	-	-	38.7	16.7	0.3	2.5	58.2
103-	7.5	5.4	0.15	-	0.14	-	-	-	-	30.0	13.8	0.2	1.3	45.3

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 %
0-13	58	30.1	94	4.8	-	-	-
13-24	77	61.5	93	3.0	-	-	-
24-60	87	41.1	92	1.1	-	-	-
60-103	88	66.4	95	2.0	-	-	-
103-	100	45.4	108	0.5	-	-	-

Profile description

Apg 0-13 cm	dark grey (5Y 4/1, moist)clay,strong coarse angular blocky,firm very sticky very plastic,many fine distinct clear mottles (2.5 YR 3/6) and many fine distinct mottles (5 YR 3/4),abrupt wavy boundary to,
Bg 13-24 cm	grey (5Y 5/1, moist)clay,weak to moderate medium angular blocky,firm very sticky very plastic,many fine mottles (5 YR 3/3),very few small soft manganiferous concretions,gradual wavy boundary to,
Bgi1 24-60 cm	dark grey (10YR 4/1, moist)clay,weak to moderate coarse angular blocky,firm very sticky very plastic,common fine distinct mottles (5 YR 3/4),broken slickensides cutans,very few small soft manganiferous concretions,gradual wavy boundary to,
Bgi2 60-103 cm	dark grey (10YR 4/1, moist)clay,weak coarse angular blocky parting to fine and medium angular blocky,firm very sticky very plastic,broken slickensides cutans,gradual wavy boundary to,
Bgi3 103- cm	dark grey (5Y 4/1, moist)clay,weak medium angular blocky,firm very sticky very plastic,many fine distinct mottles (5 Y 5/3),continuous slickensides cutans,very few small soft manganiferous concretions,

Major crops	rice
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	paddy
Remarks on Land Use / Vegetation	Additionally some vegetable crops

Altitude	10m
Physiographic Unit	alluvial plain
Physiographic position of the site	flat
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	alluvial plain
Slope	0%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	poor
Kind of ground water table (USDA, 1979)	no groundwater table observed
Estimated run off (class)	medium

Surface cracking	small cracks (width less than 1 cm, or depth less than 50 cm)
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
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none

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Reference soil Philippines 05: Vertisol

Characteristics

Reference soil PH005: Vertisols

Classification