Reference soil China 12: Regosol

CN012

Regosols are found in areas where soil has been eroded to the extent that the underlying unconsolidated materials come near to the surface, or where soil formation has not played an important role, e.g. in desert regions. The name comes from the greek 'rhegos' :blanket meaning young soils on weathering materials.

Characteristics

Soils in medium and fine textured materials, having no distinctive horizons other than an ochric horizon at the surface.

Distribution of Regosols (rough estimation supplied by soilgrids)

Reference soil CN012: Regosols

Very deep, well drained, brown silt loam; porous massive structured, (moderately?) saline. Surface characteristics: topsoil has a soft and thin platy to massive porous structured crust with "gasbubbles" porosity, which is probably caused when the melting snow or rain turns the topsoil into an mudlayer, subsequently heating by the sun expends entrapped or liberated air; soil falls immediately apart when wetted / Vegetation: about 90% bare soil; dominant species at site: Anabasis, Peterosimonia, Reaumuria, Salsola, Suadae / Land use: incidentally grazed by camels and sheep, at some kilometers distance irrigated agriculture / Notes on profile description: probably weak, very large, columnar structure is present in C1 horizon, as present cracks or "planes of weaknes" are visible; very few tiny white spots of CaCO3 or gypsum in C2 horizon.

Classification

WRB 2006

WRB 1998

Haplic- Regosol (Calcaric Hyposalic Sodic)

Hyposali-Nudiyermic- Regosol (Gypsiric Calcaric)

0-6 cm	takyric horizon
-	calcaric

0-6 cm

takyric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Nudiyermi-Calcaric Regosol salic

Haplic Xerosol saline

0-6 cm	ochric A horizon
- cm	ochric A horizon
-	calcareous

0-6 cm

ochric A horizon

Local classification:	Haplic cold desert soil; Gypsi-Orthic Aridosol
Common name:	Brown loam on loess

Other classification

USDA-NRCS (1999)	Typic Torriorthent
USDA-SCS (1975)	Typic Torriorthent torric coarse-silty mixed frigid

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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
0-6	-	0.2	0.4	0.8	2.2	10.0	13.6	29.3	41.4	70.7	15.7
6-36	-	0.1	0.2	0.3	0.6	10.9	12.1	31.7	42.5	74.2	13.7
36-77	-	0.1	0.1	0.2	0.9	20.6	21.9	32.5	30.0	62.5	15.8
77-125	-	0.1	0.1	0.1	0.6	13.4	14.3	30.2	36.9	67.1	18.7
125-160	-	0.0	0.1	0.2	1.1	22.7	24.1	32.2	23.9	56.1	19.8

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
3-8	1.415	-	-	-	-
0-6	-	-	-	-	15.7
30-35	1.379	-	-	-	-
6-36	-	-	-	-	13.7
70-75	1.367	-	-	-	-
36-77	-	-	-	-	15.8
77-125	-	-	-	-	18.7
125-160	-	-	-	-	19.8

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	1.415	45.1	43.2	39.0	30.1	26.6	23.7	17.4	14.6
30-35	1.379	52.2	49.7	46.7	39.7	33.2	23.9	14.3	11.9
70-75	1.367	51.6	49.6	45.0	38.8	33.0	25.8	13.1	11.0

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
0-6	8.6	8.3	3.40	3.6	0.73	0.10	7	-	-	40.7	3.6	2.7	2.2	49.2
6-36	8.5	8.2	4.70	3.5	0.27	0.04	7	-	-	46.4	3.6	0.9	2.4	53.3
36-77	8.6	8.3	5.40	2.5	0.14	0.02	7	-	-	102.4	3.3	0.5	7.3	113.5
77-125	8.7	8.3	4.60	3.0	0.15	-	-	-	-	43.3	3.2	0.6	3.0	50.1
125-160	9.0	8.4	3.40	2.9	0.14	-	-	-	-	36.1	3.0	0.5	4.3	43.9

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 %
0-6	-	7.6	48	2.6	-	-	29
6-36	-	7.4	54	0.9	-	-	32
36-77	-	7.2	46	0.5	-	-	100
77-125	-	6.3	34	0.5	-	-	48
125-160	-	7.0	35	0.5	-	-	61

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
0-6	-	-	-	0.10	0.10	0.50	0.00	-	-	-	0.10
6-36	-	-	-	0.10	0.10	0.50	0.00	-	-	-	0.10
36-77	-	-	-	0.10	0.10	0.50	0.00	-	-	-	0.10
77-125	-	-	-	0.10	0.10	0.60	0.00	-	-	-	0.10
125-160	-	-	-	0.10	0.10	0.50	0.00	-	-	-	0.10

Depth (cm)	CaSO4.2H2O %	P Bray mg/kg	P Olsen mg/kg	pH CaCl2	clay_noncarbonate % w/w	clay_carbonate % w/w	phosphorus4 mg/kg	phosphorus1 mg/kg	total_sulfur % w/w
0-6	0.03	-	-	-	-	-	-	-	-
6-36	0.56	-	-	-	-	-	-	-	-
36-77	2.19	-	-	-	-	-	-	-	-
77-125	0.91	-	-	-	-	-	-	-	-
125-160	0.01	-	-	-	-	-	-	-	-

Soluble sands

Depth (cm)	Ca mmol(c)/kg	Mg mmol(c)/kg	K mmol(c)/kg	Na mmol(c)/kg	sum cations mmol(c)/kg	CO3 mmol(c)/kg	HCO3 mmol(c)/kg	Cl mmol(c)/kg	NO3 mmol(c)/kg	SO4 mmol(c)/kg	sum anions mmol(c)/kg
0-6	1.16	0.5	0.4	9.2	11.3	-	0.2	7.2	1.00	2.6	11.01
6-36	1.64	0.5	0.1	9.9	12.1	-	0.1	4.7	0.60	6.3	11.72
36-77	1.52	0.5	0.0	11.0	13.07	-	0.1	7.0	0.50	6.0	13.57
77-125	1.68	0.5	0.0	12.1	14.27	-	0.1	7.2	0.40	8.1	15.78
125-160	0.84	0.3	0.0	9.9	11.09	-	0.1	5.6	0.40	3.4	9.42

Depth (cm)	Sodium ads. ratio	pH e	EC e dS/m	EC 1 : 5 dS/m
0-6	49	7.5	13.70	-
6-36	47	6.8	14.50	-
36-77	51	7.9	14.30	-
77-125	54	6.8	15.00	-
125-160	65	6.9	14.40	-

Profile description

Ah 0-6 cm	brown (10YR 5/3, dry)silty clay loam,porous massive to weak platy,hard very friable slightly sticky slightly plastic,many fine pores,clear smooth boundary to,
C1 6-36 cm	brown (10YR 5/3, dry)silty clay loam,weak very coarse columnar,hard very friable slightly sticky slightly plastic,many very fine fine pores,gradual smooth boundary to,
C2 36-77 cm	brown (10YR 5/3, dry)silty clay loam,weak fine and medium angular blocky to subangular blocky,hard very friable slightly sticky slightly plastic,many very fine fine pores,gradual smooth boundary to,
C3 77-160 cm	brown (10YR 5/3, dry)silty clay loam,weakly coherent porous massive,slightly hard very friable slightly sticky slightly plastic,very fine fine pores,

Kind 1 (parent material) ; Parker (eds), 1984	sediment, unconsolidated
Mode of accumulation or deposition of parent material	eolian loess
Remarks on Parent Materials	Pleistocene era
Soil Depth	75cm
Texture of parent material	silty

Intensity of the soil erosion type	slight
Intensity of the soil erosion type (second entry)	slight
Soil erosion type	sheet
Soil erosion type (second entry)	gully

Land use or vegetation in the immediate vicinity of the site	semi-natural grassland, grazed
Remarks on Land Use / Vegetation	VEGETATION: About 90% bare soil; dominant species: Anabasis, Peterosimonia, Reaumuria, Salsola, Suadae LANDUSE: Incidentally grazed by camels and sheep, at some kilometers distance irrigated agriculture
Major vegetation type; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	grassland

Altitude	550m
Physiographic Unit	plain N of Tian Shan Mountains
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.	piedmont
Slope	1%
Topography; Guidelines for soil description - Fourth edition (FAO, Rome, 2006)	flat or almost flat

Drainage class ; FAO (2006) - Guidelines for soil description	well
Dry From - To	0-160cm
Flooding frequency (FAO, 1986)	never
Depth to groundwater table	750cm
Kind of ground water table (USDA, 1979)	groundwater table observed
Estimated permeability (class) of least permeable part of the profile	high
Estimated run off (class)	medium

Evidence of alkali ; Soil Survey Manual USDA, 1951	strongly alkaline
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)	surface partly slaked, round smooth aggregates
Microrelief pattern	none
Rock outcrop class (FAO (2006) - Guidelines for soil description)	none
Evidence of salt; Soil Survey Manual USDA, 1951	moderately saline
Surface stoniness class (FAO (2006) - Guidelines for soil description)	none

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Reference soil China 12: Regosol

Characteristics

Reference soil CN012: Regosols

Classification