YONGHEUNG SERIES

Established Series PCS, JYH, UKT 10 Apr., 1977

  The Yongheung series are members of the fine, mixed, thermic family of Typic Palehumults [Cutanic Alisols (Hyperdystric Clayic) classified by WRB]. These soils have very dark grayish brown gravelly silty clay loam Ap horizons, very dark grayish brown gravelly clay BAt horizons, dark yellowish brown gravelly clay Bt1 horizons, dark yellowish brown gravelly clay Bt2 horizons, dark yellowish brown gravelly clay Bt3 horizons, and yellowish brown gravelly clay Bt4 horizons. These soils are developed on lava plains derived from pyroclastic materials.

Typifying Pedon: Yongheung gravelly silt loam-citrus ochard (Colors are for moist soil).

  Slope: 2-7%

  Elevation: 50 m above m.s.l.

  Soil moisture regime: Udic

  Soil temperature regime: Thermic

  Parent material: Pyroclastic materials

  Diagnostic features: An umbric epipedon from a depth of 0 to 32 cm and an argillic horizon from a depth of 15 to 150 cm (An umbric horizon from a depth of 0 to 32 cm and an argic horizon from a depth of 15 to 150 cm by WRB).

  Described by: Song, K. C., S. J. Jung, and D. C. Noh,  4 March, 2005.

Morphological properties of typifying pedon.

Ap - 0 to 15 cm. Very dark grayish brown (10YR 3/2) gravelly silty clay loam; weak fine to medium granular structure; friable, slightly sticky and slightly plastic; abundant fine to medium roots; common fine to medium pores; gradual smooth boundary.

BAt - 15 to 32 cm. Very dark grayish brown (10YR 3/2) gravelly clay; moderate fine to medium granular structure; firm, sticky and plastic; abundant medium to coarse roots; many fine to medium pores; clear smooth boundary.

Bt1 - 32 to 60 cm. Dark yellowish brown (10YR 4/4) gravelly clay; weak fine to medium subangular blocky structure; firm, very sticky and very plastic; thin patch clay cutans; common medium to coarse roots; many medium to coarse pores; clear smooth boundary.

Bt2 - 60 to 105 cm. Dark yellowish brown (10YR 4/6) gravelly clay; moderate fine to medium subangular blocky structure; firm, very sticky and very plastic; thick continuous clay cutans; few fine to medium roots; common fine to medium pores; gradual smooth boundary.

Bt3 - 105 to 130 cm. Dark yellowish brown (10YR 4/2) gravelly clay; strong fine to medium subangular blocky structure; firm, very sticky and very plastic; thick continuous clay cutans; no roots; few fine pores; common fine to medium yellowish red (5YR 4/6) Mn mottles; clear smooth boundary.

Bt4 - 130 to 150 cm. Yellowish brown (10YR 5/6) gravelly clay; moderate fine to medium subangular blocky structure; very sticky and very plastic; no roots; few fine pores; few fine to medium strong brown (7.5YR 4/6) Mn mottles. 

C   - 150 to 200 cm.

  The typifying pedon has an umbric epipedon from a depth of 0 to 32 cm and an argillic horizon from a depth of 32 to 150 cm. It has a base saturation (by sum of cations) of less than 35% at 125 cm below the upper boundary of the argillic horizon. That can be classified as Ultisol. It has 0.9% or more organic carbon in the upper 15 cm of the argillic horizon and keys out as Humult. It does not have a densic, lithic, paralithic, or petroferric contact within 150 cm of the mineral soil surface, and with increasing depth, does not clay decrease of 20% or more from the maximum clay content within 150 cm of the mineral soil surface. It can be classified as Palehumult. Also it meets the requirements of Typic Palehumult.

  The typifying pedon has more than 35% clay at the particle-size control section and has thermic soil temperature regime. Therefore it can be classified as fine, mixed, thermic family of Typic Palehumult.

Type Location: About 800 meters south-east of the Dosun Primary School, Dosun Dong, Seogwipo city, Jeju Do (126° 28' 55.2'', 33° 14' 31.6'').

Range in Characteristics: These soils have umbric epipedons and argillic horizons. Solum thickness ranges from 150 to 200 cm. Reaction is very strongly to medium acid. Base saturation is more than 50 percent. Ap horizons are dark brown or very dark grayish brown gravelly silt loam to silty clay loam. Bt horizons are dark yellowish brown, yellowish brown, or strong brown gravelly silty clay or clay.

Competing Series and Their Differentiae: These are the Jeju and Hawon series. The Jeju soils are Andic Subgroups and gravel free. The Hawon soils are belonged to Humic Hapludults.

Setting: The Yongheung soils occur on gently sloping low lava plains and are derived from pyroclastic materials. Slope ranges from 2 to 15 percent and dominant slopes are 2 to 7 percent.

Principal Associated Soils: The Jeju, Hawon soils are associated on similar physiographic positions.

Drainage and Permeability: Well drained. Runoff is medium and permeability is very slow.

Use and Vegetation: Most of these soils are used for upland crops such as oil vegetable or barley.

Distribution and Extent: The Yongheung soils are of small extent and are distributed on low lava plains in southwestern parts of Jeju Do.

Series Established: Seogwipo city, Jeju Do, 1975. Revised, Seogwipo city, Jeju Do, 2005.

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) - - - - - - - - - - -
0-15	Ap	38.8	50.5	10.7					3.1	2.5	1.9	2.4	0.8
15-32	BAt	59.7	33.8	6.5					2.4	1.8	0.9	0.8	0.7
32-60	Bt1	59.3	33.5	7.2					3.3	2.1	0.9	0.6	0.3
60-105	Bt2	52.4	35.8	11.8					5.1	4.5	1.5	0.6	0.1
105-130	Bt3	52.1	38.0	9.9					4.0	2.7	1.5	1.3	0.4
130-150	Bt4	58.3	31.9	9.8					4.4	2.9	1.3	0.8	0.3
150-200	C	34.1	61.8	4.1					1.0	1.1	1.1	0.9	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

0-15

2.13

15-32

1.43

32-60

0.93

60-105

0.39

105-130

0.31

130-150

0.47

150-200

0.12

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
0-15	0.61						1.21		27.1	33.9	29.2
15-32	0.29						1.42		23.4	30.2	27.7
32-60	0.28						1.29		36.1	33.0	30.4
60-115	0.31						1.33		38.6	37.5	35.0
115-130	0.31						1.29		42.9	41.5	38.0
130-150	0.31						1.30		39.4	41.3	36.7
150-200	0.56						-			47.1	41.0

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
0-15	1.1	0.4	0.33	0.1	1.9	40.0	4.7	41.9	23.6	6.6
15-32	0.5	0.3	0.36	0.1	1.3	32.5	4.1	33.8	17.1	5.4
32-60	3.8	2.2	1.48	0.1	7.6	21.5	0.2	29.1	16.9	7.8
60-115	4.5	1.8	1.23	0.1	7.6	18.0	0	25.6	16.1	7.6
115-130	4.9	2.0	0.65	0.2	7.8	18.0	0	25.8	15.9	7.8
130-150	4.2	2.0	0.43	0.2	6.8	23.5	0.1	30.3	17.9	6.9
150-200	5.4	2.5	0.51	0.1	8.5	22.5	0	31.0	19.2	8.5

Depth (cm)	(Base Sat)		CO3 as	Res	P Ret	(------ pH ------)				Acid Oxalate Extraction
	Sum	NH4-	CaCO3			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	Pct		1: 1	1: 2	1: 1		- Pct of ˂2mm -
0-15	4.6	8.2			74.4		3.3	3.8	4.2		1.62	1.87	0.43
15-32	3.7	7.4			88.4		3.5	3.9	4.0		1.58	1.54	0.47
32-60	26.1	44.9			88.1		4.3	4.8	5.1		1.48	1.54	0.37
60-115	29.8	47.4					5.0	5.3	5.4
115-130	30.1	48.7					5.1	5.4	5.5
130-150	22.5	38.2					4.5	4.9	5.0
150-200	27.4	44.3					4.9	5.3	5.4