Reference soil China 42: Leptosol

CN042

Leptosols are by far the most extensive group of soils in the world. They are found mainly in mountainous regions and in areas where soil has been eroded to the extent that hard rock comes near to the surface. Other (minor) occurrences are along rivers where gravely deposits have accumulated without substantial admixture of fine earth material.

Characteristics

Soils which are either limited in depth by continuous hard rock within 25 cm from the soil surface, or overly mayerial with a calcium carbonate equivalent of more than 40 percent within 25 cm from the soil surface, or contain less than 10 percent (by weight) fine earth (mineral soil material with a diameter of 2 mm or less) to a depth of 75 cm from the soil surface. Leptosols have no diagnostic horizons other than a mollic, ochric, umbric, vertic or yermic horizon.

Distribution of Leptosols (rough estimation supplied by soilgrids)

Reference soil CN042: Leptosols

PROFILE DESCRIPTION : Deep, excessively drained, brown to black gravel derived from 270 year old volcanic ejecta. The volcanic soil material has been only slightly altered. The soil has a medium content in organic carbon and a neutral soil reaction throughout. GENERAL LANDFORM: The Heilungshan volcano erupted 1719-21, the years 58 - 60 of the reign of Qin emperor Kangsi. At the same time the Hoshoushan volcano, some 5 km NE, was active. The Heilungshan volcano is situated on a rather small basalt plateau (estimated 50 sqkm) of the same age SURFACE DRAINAGE: The disturbance of the drainage pattern by the basalt flow is reflected in the name Wu da lian chi: five-large-interconnected-lakes, which refers to the lava-forced moving of the river to the east and creating a number of natural reservoirs PARENT MATERIAL: the actual basalt plateau is situated on a larger basalt plateau (some 1600 sq km in the geological map), consisting of three known sheets dating from 1.3, 0.8-0.9 and 0.3-0.65 my ago (K Ar dating). According to its composition it is of a rather rare type, having a relatively high K and Si content and a relatively low Ca content. These older basalts are covered by loess(like) deposits. Apart from the lavaflow ash was deposited. These ashes are rather coarse and are mainly found on the lava field. The loess-like deposits bordering the volcano have only been contaminated with (finer) ash materials in the upper cm or less. This mixed layer may be the result of plowing since plowing to about 18 cm is combined with ridge and furrow cultivation of some 15 cm height / CLIMATE: additional climatic data are available for the weather stations of Keshan (48 3 N/125 52 E; 237 m a.s.l.; 77 km SW of site; relevance: poor to moderate) and Nenjiang (49 10 N/125 14 E; 242 m a.s.l.; 83 km NW of site; relevance; poor to moderate).

Classification

WRB 1998

Hyperskeleti-Vitric- Leptosol (Eutric)

0-20 cm

ochric horizon

FAO-UNESCO-ISRIC 1988

FAO-UNESCO-ISRIC 1974

Epiandi-Dystric Leptosol skeletic

Eutric Regosol petric

0-20 cm	ochric A horizon
- cm	ochric A horizon
-	andic

0-20 cm	ochric A horizon
-	exchange complex dominated by amorphous material

Local classification:	Cinderic andisol; Usti-Vitric Andosol

Other classification

USDA-SCS (1975)

Ustorthent ustic ashy-skeletal mixed frigid

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
0-20	-	34.1	24.8	13.7	9.5	2.6	84.7	5.6	3.6	9.2	6.1
20-50	-	29.6	27.9	14.2	9.2	5.9	86.8	6.0	3.0	9.0	4.2
60-110	-	38.7	28.3	12.4	8.6	4.3	92.3	4.0	1.5	5.5	2.1

Water retention characteristics

Depth (cm)	Bulk density kg/dm³	Spec. Surf. Area m²/g	COLE cm/cm	Water disp. clay %	Clay % w/w
0-20	-	-	-	-	6.1
20-50	-	-	-	-	4.2
60-110	-	-	-	-	2.1

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
0-20	6.8	6.3	0.15	0.4	1.66	0.12	14	-	-	7.9	2.0	0.7	0.3	10.9
20-50	6.8	5.9	0.04	0.3	0.30	0.05	6	-	-	3.4	1.8	0.2	0.4	5.8
60-110	7.5	6.8	0.10	1.1	0.04	0	-	-	-	0.8	0.8	0.1	0.3	2

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 %
0-20	104	10.5	172	5.8	-	-	3
20-50	70	8.3	198	1.1	-	-	5
60-110	43	4.6	219	0.1	-	-	7

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
0-20	7.5	19	-	0.23	0.15	-	-	-	-	-	0.27
20-50	8.1	60	-	1.16	0.75	0	-	-	-	-	0.15
60-110	7.5	33	-	0.31	0.33	-	-	-	-	-	0.05

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
0-20	-	-	19.5	-	-	-	-	-	-
20-50	-	-	8.5	-	-	-	-	-	-
60-110	-	-	21.8	-	-	-	-	-	-

Clay mineralogy

Depth (cm)	Chlorite	Feldspar	Gibbsite	Goethite	Halloysite	Hematite	Kaolinite	Mica / illite	Mixed-layer	Quartz	Smec	Vermiculite
0-20	-	-	-	-	-	-	weak	weak	weak	very weak	-	-

Profile description

Ah 0-20 cm	brown (7.5YR 5/2, dry) (7.5YR 2/1, moist)gravel,leaves leaves,highly porous (>60 vol%),very frequent medium gravel weathered volcanic ash very frequent fine gravel weathered volcanic ash fragments,abrupt smooth boundary to,
AC 20-50 cm	(dark) brown (7.5YR 4/2, moist)loamy coarse sand gravelly,leaves,(2.5YR 6/8) and (2.5YR 2/2),highly porous (>60 vol%),very frequent fine gravel weathered volcanic ash very frequent medium gravel weathered volcanic ash fragments,gradual smooth boundary to,
C 50-110 cm	coarse sand gravelly(2.5YR 4/6) and (2.5YR 6/8),highly porous (>60 vol%),very frequent fine gravel fresh volcanic ash very frequent medium gravel fresh volcanic ash fragments,frequent mycelium,

Mode of accumulation or deposition of parent material	ejecta ash
Remarks on Parent Materials	270 yr old volc. ash
Soil Depth	100cm

Land use or vegetation in the immediate vicinity of the site	(semi-)natural vegetation
Remarks on Land Use / Vegetation	VEGETATION: Open birch-larch forest, mosses, lichens
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)	deciduous woodland

Altitude	400m
Physiographic Unit	volcano on nearly level plain
Physiographic position of the site	lower slope
Regional landform; McDonald, R.C., Isbell, R.F. et all, 1984; Australian soil and land survey Field Handbook, Inkata Press, Melbourne.	volcano
Slope	14%
Slope Aspect	south
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	excessive
Kind of ground water table (USDA, 1979)	no groundwater table observed
Moist From - To	0-110cm
Estimated run off (class)	rapid

Evidence of alkali ; Soil Survey Manual USDA, 1951	non-alkaline
Average size of stone	50
Surface cracking	no cracks observed
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)	little rocky
Evidence of salt; Soil Survey Manual USDA, 1951	non-saline
Shape of stones (on average)	angular irregular
Surface stoniness class (FAO (2006) - Guidelines for soil description)	stony

You are here

Reference soil China 42: Leptosol

Characteristics

Reference soil CN042: Leptosols

Classification