The Nogsan series are members of the medial, ferrihydritic, thermic family of Typic Melanudands [Melanic Silandic Andosols (Dystric Siltic) classified by WRB]. These soils have black silt loam A horizons, very dark brown silt loam AB horizons, dark brown silt loam Bw1 horizons, dark reddish brown silt loam Bw2 horizons, and dark reddish brown silty clay loam BC horizons. They are developed on cinder cones and are derived from pyroclastic materials.

Typifying Pedon: Nogsan silt loam-forest (Colors are for moist soil).

  Slope: 30-60%

  Elevation: 344 m above m.s.l.

  Soil moisture regime: Udic

  Soil temperature regime: Thermic

  Parent material: Pyroclastic materials

  Diagnostic features: A melanic epipedon from a depth of 0 to 42 cm, a cambic horizon from a depth of 42 to 100 cm, and andic soil properties from a depth of 0 to 180 cm (A melanic horizon from a depth of 0 to 42 cm, a cambic horizon from a depth of 42 to 100 cm, and andic properties from a depth of 0 to 180 cm by WRB).

  Described by: Song, K. C., D. C. Noh, and B. K. Hyun,  22 Feb., 2012.

Morphological properties of typifying pedon.

A - 0 to 21 cm. Black (10YR 2/1) silt loam; moderate fine to medium granular structure; friable, slightly sticky and slightly plastic; many fine to medium roots; few fine pores; few worm holes; 5% gravels; gradual wavy boundary.

AB - 21 to 42 cm. Very dark brown (10YR 2/2) silt loam; moderate medium to coarse subangular blocky structure; friable, slightly sticky and slightly plastic; common fine to medium roots; common fine to medium pores; few worm holes; few stones; clear wavy boundary.

Bw1 - 42 to 78 cm. Dark brown (7.5YR 3/2) silt loam; moderate medium to coarse subangular blocky structure; friable, sticky and plastic; few fine to medium roots; common medium to coarse pores; few worm holes; clear wavy boundary.

Bw2 - 78 to 100 cm. Dark reddish brown (5YR 3/3) silt loam; weak coarse subangular blocky structure; friable, sticky and plastic; few fine roots; few medium pores; few worm holes; few cinders; clear wavy boundary.

BC - 100 to 180 cm. Dark reddish brown (5YR 3/3) silty clay loam; weak coarse subangular blocky structure; slightly firm, sticky and plastic; thin patch clay cutans; no roots; few medium pores; few worm holes; 5% cinders.

  The typifying pedon contains 2.4-5.4% oxalate extractable (Al + 1/2 Fe), over 85% phosphate retention, and lower bulk density than 0.90 g/m³ from the depth of 0 to 160 cm. It has andic soil properties and keys out as Andisol. The typifying pedon has an udic soil moisture regime and can be classified as Udand. A and BA horizons (0-42 cm) have a color value, moist, and chroma of 2 or less, melanic index of 1.70 or less, and 6% or more organic carbon. It meets the requirements of Typic Melanudand.

  The typifying pedon has a fine-earth fraction that has a water content at 1,500 kPa tension of 12% or more on air-dried samples and has less than 35% (by volume) rock fragments. Thus, the substitute for particle-size class is medial. It has a sum of 8 times the Si (percent by weight extracted by ammonium oxalate from the fine-earth fraction) plus 2 times the Fe (percent by weight extracted by ammonium oxalate from the fine-earth fraction) of 5 or more, and 8 times the Si is less than 2 times the Fe. It has ferrihydritic mineralogy class and thermic soil temperature class. Therefore it can be classified as medial, ferrihydritic, thermic family of Typic Melanudand.

Type Location: Southern slope of the Ujinjebi Oreum, Seonheul Ri, Gujwa Eub, Jeju city, Jeju Do (126° 42' 14.0'', 33° 27' 54.4'').

Range in Characteristics: These soils have melanic epipedons, cambic horizons, and andic soil properties. The solum thickness ranges from 100 to 200 cm and depth to hard rock is more than 3 meters. Soil reaction is strongly to slightly acid. Base saturation is less than 50 percent. A horizons are black or very dark brown silt loam or silty clay loam. Cambic B horizons are reddish brown, yellowish red, or red silt loam or silty clay loam. C horizons are reddish brown, yellowish red, yellowish brown, or strong brown fine sandy loam or loam with some cinders.

Competing Series and Their Differentiae: These are the Byeongag, Euigwi, and Geumag soils. The Byeongag soils have medial over cindery texture class. The Euigwi soils occur on lava plains. The Geumag soils are Pachic Subgroups.

Setting: The Nogsan soils occur on cinder cones and are derived from pyroclastic materials.  Slope ranges from 7 to 60 percent. Dominant slopes are 15 to 30 percent.

Principal Associated Soils: The Byeongag, Geumag, Miag, and Songag soils are associated on similar physiographic positions.

Drainage and Permeability: Well drained. Permeability is moderately rapid. Runoff is medium to rapid.

Use and Vegetation: Most of these soils are used for grass land.

Distribution and Extent: The Nogsan soils are of small extent and are distributed on cinder cones of Jeju Do.

Series Established: Jeiu city, Jeju Do, 1975. Revised, Jeiu city, Jeju Do, 2012.

Laboratory data sheets of typifying pedon.

Depth (cm)	Horizon	( --- Total ---)			(-- Clay --)		(-- Silt --)		(------- Sand -------)
		Clay	Silt	Sand	Fine	Coarse	Fine	Coarse	VF	F	M	C	VC
		LT	.002	.05	LT	LT	.002	.02	.05	.10	.25	.5	1
		.002	- .05	- 2	.0002	.002	- .02	- .05	- .10	- .25	- .50	- 1	- 2
		- - - - - - - - - - - Pct of ˂ 2mm (3A1) - - - - - - - - - - -
0-21	A	28.0	66.8	5.2			39.0	27.8	1.0	1.8	1.2	0.9	0.3
21-42	AB	28.8	59.4	11.8			36.1	23.3	4.5	4.6	1.5	0.9	0.3
42-78	Bw1	23.2	65.9	10.9			30.3	35.5	3.7	4.1	1.7	1.0	0.5
78-100	Bw2	25.2	66.8	8.0			29.1	37.7	2.6	2.9	1.2	0.9	0.3
100-180	BC	28.9	63.7	7.4			23.4	40.3	2.7	3.2	0.9	0.5	0.1

Depth (cm)

Coarse Fractions(mm)

˃2mm

Orgn

Total

Extr

Total

(-- Dith -Cit --)

Weight

Wt

C

N

P

S

Extractable

2-5

5-20

20-75

.1-75

Pct of

Fe

Al

Mn

Whole

6A1c

6B3a

6S3

6R3a

6C2b

6G7a

6D2a

Pct of ˂ 75mm (3B1)

Soil

Pct ˂ 2mm

g/kg

Pct of ˂ 2mm

0-21

12.34

21-42

6.97

42-78

4.64

78-100

3.27

100-180

1.09

Depth (cm)

Ratio/Clay

Atterberg

( Bulk Density )

COLE

(- Water Content -)

WRD

CEC

1500

Limits

Field

33

Oven

Whole

Field

10

33

1500

Whole

kPa

LL

PI

Moist

kPa

Dry

Soil

Moist

kPa

kPa

kPa

Soil

8D1

8D1

4P1

4P

4A3a

4A1d

4A1h

4D1

4B4

4B1c

4B1c

4B2a

4C1

Pct ˂0.4mm

- - g/cc - -

cm/cm

-- Pct of ˂2mm --

cm/cm

0-21

1.7

0.51

114.9

21-42

1.4

0.56

115.4

42-78

1.6

0.68

94.6

78-100

1.3

0.71

86.4

100-180

0.9

Depth (cm)	( NH4OAc Extractable Bases )					Acid-	Extr	(----- CEC -----)			Al
	Ca	Mg	K	Na	Sum	ity	Al	Sum	NH4-	Bases	Sat
	5B5a	5B5a	5B5a	5B5a	Bases			Cats	OAc	+ Al
	6N2e	6O2d	6Q2b	6P2b		6H5a	6G9a	5A3a	5A8b	5A3b	5G1
	- - - - - - - - - - - - meq / 100g - - - - - - - - - - - -										Pct
0-21	1.5	1.2	0.7	0.3	3.7	74.8	3.4	78.6	48.3	7.1	48.4
21-42	0.5	0.9	0.2	0.3	2.0	53.6	0.6	55.6	40.7	2.6	23.7
42-78	0.7	1.5	0.1	0.4	2.8	44.8	0	47.7	36.3	2.8	0
78-100	1.6	2.5	0.1	0.7	4.9	33.3	0	38.2	32.7	4.9	0
100-180	1.8	4.6	0.2	0.6	7.1	22.7	0.1	29.8	24.9	7.2	1.2

Depth (cm)	(Base Sat)		CO3 as	Res	P	(------ pH ------)				Acid Oxalate Extraction
	Sum	NH4-	CaCO3		Ret	NaF	KCl	CaCl2	H2O	Opt	Al	Fe	Si
		OAc	˂2mm					.01M		Den
	5C3	5C1	6E1g	8E1		8C1d		8C1f	8C1f	8J	6G12	6C9a	6V2
	---- Pct ----			ohms/cm	%		1: 1	1: 2	1: 1		- Pct of ˂2mm -
0-21	4.7	7.6			99.2		4.4	4.8	5.3		3.8	3.2	0.33
21-42	3.6	4.9			99.4		4.7	4.9	5.6		3.4	3.1	0.48
42-78	5.9	7.7			99.2		4.9	5.0	5.8		3.1	3.5	0.69
78-100	12.9	15.1			98.3		4.8	5.1	6.0		2.8	3.6	0.66
100-180	23.9	28.6			91.8		4.7	5.1	6.1		1.3	2.2	0.33