The Jangwon series are members of the fine loamy, mixed, mesic family of Typic Fragiudalfs [Umbric Cutanic Alisols (Fragic Humic Siltic) classified by WRB]. These soils have very dark grayish brown loam Ap horizons, dark brown gravelly loam AB horizons, dark yellowish brown gravelly clay loam Bt horizons and dark yellowish brown silty clay loam Btx horizons. They are formed in dissected foot slope positions derived from granite, porphyry and shale materials.

Typifying pedon: Jangwon gravelly loam-forest (Colors are for moist soil).

  Slope: 7-15%

  Elevation: 157 m above m.s.l.

  Soil moisture regime: Udic

  Soil temperature regime: Mesic

  Parent material: Colluvium from acidic crystaline rocks

  Diagnostic features: An umbric epipedon from a depth of 0 to 20 cm, an argillic horizon from a depth of 48 to 150 cm, and a fragipan from a depth of 80 to 150 cm (An umbric horizon from a depth of 0 to 20 cm, an argic horizon from a depth of 48 to 150 cm, and a fragic horizon from a depth of 80 to 150 cm by WRB).

  Described by: Song, K. C., S. J. Jung, and D. C. Noh,  16 March, 2010.

Ap - 0 to 20 cm. Very dark grayish brown (10YR 3/2) loam; weak fine to medium subangular blocky structure; friable, slightly sticky and slightly plastic; many fine to medium roots; common fine pores; clear smooth boundary.

AB - 20 to 48 cm. Dark brown (10YR 3/3) gravelly loam; weak fine to medium subangular blocky structure; friable, sticky and plastic; common fine to medium roots; common fine pores; 15% gravels; few worm holes; clear smooth boundary.

Bt - 48 to 82 cm. Dark yellowish brown (10YR 4/4) gravelly clay loam; moderate fine to medium angular blocky structure; firm, sticky and plastic; thin continuous clay cutans; common fine to medium roots; common fine pores; 20% gravels; clear smooth boundary.

Btx - 82 to 150 cm. Dark yellowish brown (10YR 4/3) silty clay loam; strong medium to coarse angular blocky structure; very firm, very sticky and very plastic; thick continuous clay cutans; no roots; few fine pores.

  The typifying pedon has an umbric epipedon from a depth of 0 to 20 cm and an argillic horizon from a depth of 48 to 150 cm. It has a base saturation (by sum of cations) of 35% or more at 125 cm below the upper boundary of the argillic horizon. That can be classified as Alfisol. It has udic soil moisture regime, and can be classified as Udalf. It has a fragipan within 100 cm of the mineral soil surface and keys out as Fragiudalf. Also it meets the requirements of Typic Fragiudalf.

  The typifying pedon has fine loamy particle-size class and mesic soil temperature class. Therefore it can be classified as fine loamy, mixed, mesic family of Typic Fragiudalf.

Type Location: About 200 meters west of the Jeomchon Village, Daeil Ri, Gachang Myeon, Dalseong Gun, Daegu city (128^o 38' 58.0'', 35^o 45' 48.9'').

Range in Characteristics: These soils have umbric epipedo, and fragipans. Solum thickness is 100 to 200 cm and depth to hard rock is generally more than 3 meters. The fragipans generally occur between 50 and 100 cm. Base saturation is more than 35 percent. Reaction is strongly to slightly acid. Ap horizons are very dark grayish brown gravelly silt loam or loam. AB horizons are dark brown gravelly silt loam or loam. Bt horizons are dark yellowish brown gravelly clay loam. Btx horizons are very firm or extremely firm, when dry and do not soften appreciably when moist. They are dark yellowish brown, pale brown, strong brown, or brown gravelly silty clay loam or clay loam. 

Competing Series and Their Differentiae: These are the Yeongog, Pogog, and Gangreung series. The Yeongog soils are gravel free fine silty texture family. The Pogog soils have fine texture and are derived from granite gneiss. The Gangreung soils have fine textures occur on river terraces.

Setting: The Jangwon soils occur on gently sloping to moderately steep alluvial-colluvial foot slopes. Dominant slopes are 7 to 30 percent and range is from 2 to 60 percent.

Principal Associated Soils: The Mudeung, Ulsan, Daegu, and Samgag soils are associated in higher residual landscape positions. The Anryong, Gaghwa and Iwon soils are associated in similar landscape positions. The Jisan and Sangju soils may be associated below the Jangwon soils.

Drainage and Permeability: The Jangwon soils are moderately well drained and very slowly permeable. The runoff is moderate or rapid depending on the slopes.

Use and Vegetation: Most areas are used for tobacco, barley, soybean, sesame, melon, millet, red pepper, buckwheat, and similar non irrigated upland crops.

Distribution and Extent: The Jangwon soils are of small extent and occur in small areas throughout the country.

Series Established: Gwangsan Gu, Gwangju city, 1966. Revised, Dalseong Gun, Daegu city, 2010.

Laboratory data sheets of typifying pedon.