Reference soil China 02: Stagnosol

CN002

Stagnosols are often related to Luvisols and occur for the greater part in humid and perhumid temperate regions in West and Central Europe, North America, Australia and Argentina.

Characteristics

Soils having within 50 cm of the soil surface reducing conditions (soil conditions with low redox potential (negative logarithm of the hydrogen potential (rH) and presence of free iron (Fe2+) on freshly broken surfaces) and in 50% of the layer a stagnic colour pattern (strong mottling of soils in such a pattern that peds surfaces are lighter (at least one Munsell value) and paler (at least one chroma) than ped interiors, which are more reddish and brighter (at least one chroma)). The stagnic color pattern develops under temporarily saturation of a perched water table from surface water, long enough to allow reducing conditions to arise. The topsoil can be bleached and concretions can occur in the subsoil. They develop often in slowly permeable, unconsolidated materials of various origins.

Distribution of Stagnosols (rough estimation supplied by soilgrids)

Reference soil CN002: Stagnosols

Very deep, poorly drained, strongly mottled yellowish brown silty clay loam in Holocene alluvial deposits derived from Pleistocene (Xia Shu) loess. The soil is artificially submerged. The topsoil is frequently puddled (a muddy layer 5-10cm thick occurs at the surface) and has a porous massive appearance. Organic carbon content is low. The subsoil has weak to moderate subangular blocky, locally prismatic structures. The overall soil reaction is slightly alkaline. PHYSIOGRAPHY: site is surrounded by undulating hills / HYDROLOGY: surface drainage is controlled by ditches and sluices / LAND USE AND HUMAN INFLUENCES: puddling; submerging; weed control by hand; the surrounding hills are used for vegetable and tea production / MORPHOLOGY: throughout the profile small brick and pottery fragments occur / SOIL FAUNA: some worms.

Classification

WRB 2006

WRB 1998

Haplic- Stagnosol (Anthric)

Calcari-Stagnic- Cambisol

17-120 cm	cambic horizon
-	reducing conditions
-	stagnic colour pattern

0-17 cm	ochric horizon
17-120 cm	cambic horizon
-	stagnic

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Gleyi-Calcaric Cambisol anthraquic

Gleyic Cambisol phreatic

0-17 cm	ochric A horizon
17-120 cm	cambic B horizon
- cm	cambic B horizon
- cm	ochric A horizon
-	calcareous

0-17 cm	ochric A horizon
17-120 cm	cambic B horizon

Local classification:	Haplic yellow brown soil; Ochri-Aquic Cambosol
Common name:	Paddy soil, loamy alluvium

Other classification

USDA-SCS (1975)

Eutrochrept aquic fine-silty mixed thermic

More images

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
0-17	-	0.1	0.1	0.1	0.3	1.1	1.7	26.6	39.3	65.9	32.3
17-40	-	0.0	0.1	0.1	0.3	0.8	1.3	29.7	37.9	67.6	31.0
40-70	-	0.0	0.0	0.1	0.1	1.2	1.4	28.8	39.2	68.0	30.6
70-95	-	0.0	0.1	0.1	0.2	0.8	1.2	28.3	39.3	67.6	31.3
95-120	-	0.1	0.1	0.1	0.1	0.5	0.9	22.5	43.2	65.7	33.4

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
6-11	1.538	-	-	-	-
0-17	-	-	-	-	32.3
17-40	-	-	-	-	31.0
27-32	1.599	-	-	-	-
53-58	1.612	-	-	-	-
40-70	-	-	-	-	30.6
70-95	-	-	-	-	31.3
97-102	1.619	-	-	-	-
95-120	-	-	-	-	33.4

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
6-11	1.538	43.2	42.7	41.7	39.9	39.2	37.7	29.9	25.7
27-32	1.599	41.4	40.5	39.2	37.1	36.2	34.6	28.9	24.9
53-58	1.612	43.3	42.1	40.2	38.0	37.1	35.4	28.2	24.3
97-102	1.619	40.7	40.5	39.5	37.8	37.0	35.7	33.6	28.5

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
0-17	7.0	5.7	0.77	-	0.96	0.11	9	-	-	12.0	4.8	0.2	0.2	17.2
17-40	7.7	6.0	0.16	3.1	0.25	0.07	4	-	-	11.2	4.9	0.2	0.2	16.5
40-70	7.7	5.7	0.13	3.3	0.16	-	-	-	-	12.0	5.5	0.2	0.2	17.9
70-95	7.6	5.6	0.12	3.8	0.25	-	-	-	-	10.7	5.6	0.3	0.2	16.8
95-120	7.5	5.6	0.13	3.4	0.25	-	-	-	-	12.0	6.4	0.3	0.0	18.7

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 %
0-17	102	16.8	52	3.4	-	-	1
17-40	120	13.8	45	0.9	-	-	1
40-70	136	13.2	43	0.6	-	-	1
70-95	120	14.0	45	0.9	-	-	1
95-120	119	15.7	47	0.9	-	-	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
0-17	-	-	-	0.13	0.06	1.27	0.16	0.08	0.02	-	0.55
17-40	-	-	-	0.13	0.04	1.50	0.25	0.04	0.03	-	0.21
40-70	-	-	-	0.11	0.06	1.44	0.17	0.03	0.02	-	0.28
70-95	-	-	-	0.11	0.06	1.43	0.20	0.04	0.02	-	0.36
95-120	-	-	-	0.12	0.04	1.50	0.18	0.04	0.02	-	0.46

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-17	-	weak	-	weak	-	-	medium to strong	medium to strong	weak	-	-	strong
17-40	-	weak	-	weak	-	-	medium to strong	medium to strong	weak	-	-	medium to strong
40-70	-	weak	-	weak	-	-	medium to strong	medium to strong	weak	-	-	medium to strong
70-95	-	weak	-	weak	-	-	medium to strong	medium to strong	weak	-	-	medium to strong
95-120	-	weak	-	weak	-	-	medium to strong	medium to strong	weak	-	-	strong

Profile description

Apg 0-17 cm	dark greyish brown (2.5Y 4/2, moist)silty clay loam,structureless porous massive,firm slightly sticky slightly plastic,many medium distinct clear mottles (7.5YR 4/4) and many coarse distinct mottles (7.5YR 4/4),few very fine fine discontinuous inped tubular pores,very few medium gravel weathered slate fragments,abrupt smooth boundary to,
Btg1 17-40 cm	light olive brown (2.5Y 5/4, moist)silty clay loam,weak medium subangular blocky,firm slightly sticky plastic,many medium distinct clear mottles (7.5YR 5/4) and many coarse distinct mottles (7.5YR 4/6),broken moderately thick clay and sesquioxide cutans,common very fine fine discontinuous inped tubular pores,very few small spherical soft manganiferous concretions,very few medium gravel weathered slate fragments,clear smooth boundary to,
Btg2 40-70 cm	yellowish brown (10YR 5/4, moist)silty clay loam,moderate medium prismatic,friable slightly sticky plastic,many medium distinct clear mottles (7.5YR 5/6) and many coarse distinct mottles (5B 4/1),broken moderately thick clay and sesquioxide cutans,common very fine fine discontinuous inped tubular pores,very few small spherical soft manganiferous concretions,very few medium gravel weathered slate fragments,gradual smooth boundary to,
Btg3 70-95 cm	yellowish brown (10YR 5/4, moist)silty clay loam,moderate medium and coarse subangular blocky,slightly sticky plastic,many medium distinct clear mottles (7.5YR 5/6) and many coarse distinct mottles (10YR 6/2),continuous moderately thick clay and sesquioxide cutans,common very fine fine discontinuous inped tubular pores,very few small spherical soft manganiferous concretions,very few medium gravel weathered slate fragments,gradual smooth boundary to,
Bg 95-120 cm	dark yellowish brown (10YR 4/4, moist)silty clay loam,weak medium subangular blocky,sticky plastic,many medium distinct clear mottles (10YR 5/6) and many coarse distinct mottles (10YR 6/3),broken moderately thick clay and sesquioxide cutans,few very fine fine discontinuous inped tubular pores,few small spherical soft manganiferous concretions,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	fluvial
Remarks on Parent Materials	derived from loess
Soil Depth	120cm
Texture of parent material	clayey

Major crops	rice
Land improvements ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	terracing
Main type of irrigation; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	paddy
Land use or vegetation in the immediate vicinity of the site	arable farming
Remarks on Land Use / Vegetation	LANDUSE: Paddy rice-wheat rotation
Rotation scheme ; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	continuous crop rotation

Altitude	20m
Physiographic Unit	terraced valley bottom surrounded by undulating hills
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.	valley
Slope	1%
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	17cm
Drainage class ; FAO (2006) - Guidelines for soil description	poor
Flooding frequency (FAO, 1986)	yearly
Nature of flood water	fresh
(Estimated) maximum (lower) depth to groundwater table	100cm
Depth to groundwater table	90cm
Kind of ground water table (USDA, 1979)	groundwater table observed
(Estimated) minimum (upper) depth to groundwater table	0cm
Moist From - To	17-90cm
Estimated permeability (class) of least permeable part of the profile	slow
Estimated run off (class)	ponded
Upper limit of a slow permeable or stagnating layer in the profile	0cm
Wet From To	0-17cm

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
Microrelief Height: variation in height	12
Micro relief type: small-scale differences in relief in the direct vicinity of the site (FAO, 1986)	artificial terracing/mounds
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 China 02: Stagnosol

Characteristics

Reference soil CN002: Stagnosols

Classification