LOCATION CHINATOWN MT
Established Series
REV. KTS-GFB
01/2012
CHINATOWN SERIES
The Chinatown series consists of moderately deep, well drained soils that formed in colluvium and residuum derived from interbedded shale, siltstone and sandstone. These soils occur on hills. Slopes are 4 to 35 percent. Mean annual precipitation is about 300 mm, and the mean annual temperature is about 5 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aridic Haplustalfs
TYPICAL PEDON: Chinatown loam, in rangeland on a 5 percent slope at an elevation of 1850 meters (Colors are for dry soil unless otherwise noted).
A--0 to 8 cm; grayish brown (10YR 5/2) loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine and fine irregular pores; 10 percent gravel; neutral (pH 6.6); clear smooth boundary. (5 to 10 cm thick)
Bt--8 to 23 cm; brown (10YR 5/3) clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; common very fine irregular pores; 95 percent distinct clay films on all faces of peds; 10 percent gravel; neutral (pH 6.8); gradual wavy boundary. (15 to 40 cm thick)
Btk--23 to 36 cm; light reddish brown (2.5YR 6/3) loam, reddish brown (2.5YR 5/3) moist; moderate medium subangular blocky structure; hard, friable, moderately sticky and moderately plastic; many very fine and fine roots; common very fine irregular pores; 20 percent faint clay films on all faces of peds; 10 percent gravel; finely disseminated calcium carbonate, and 5 percent fine and medium irregular soft masses of calcium carbonate throughout; strongly effervescent; moderately alkaline (pH 7.9); gradual wavy boundary. (0 to 18 cm thick)
Bk--36 to 56 cm; light reddish brown (2.5YR 7/3) gravelly loam, light reddish brown (2.5YR 6/4) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine irregular pores; 20 percent gravel; finely disseminated calcium carbonate, and 30 percent fine and medium soft masses and threads of calcium carbonate throughout; violently effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (15 to 35 cm thick)
BCk--56 to 71 cm; light yellowish brown (10YR 6/4) very gravelly loam, reddish brown (2.5YR 5/4) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine irregular pores; 55 percent gravel; finely disseminated calcium carbonate and 30 percent fine and medium soft masses and threads of calcium carbonate throughout; violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (0 to 20 cm thick)
R--71 to 152 cm; siltstone bedrock.
TYPE LOCATION: Beaverhead County, Montana; located about 305 feet east and 2030 feet south of the northwest corner of sec. 6, T. 10 S., R 12 W; Jeff Davis Peak topographic quadrangle; UTM 12T, 332134e, 4984511n. NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C.
Depth to top of argillic horizon - 5 to 10 cm
Depth to secondary calcium carbonate - 20 to 45 cm
Depth to a lithic contact - 50 to 100 cm
Particle-size control section - averages 20 to 35 percent clay
Note: Some pedons have a thin Cr horizon above the R.
A horizon
Value: 4 or 5 dry; 3 or 4 moist
Chroma: 2 or 3; dry or moist
Texture: loam or sandy clay loam
Clay content: 15 to 26 percent
Rock fragments: 0 to 25 percent--0 to 20 percent gravel, 0 to 15 percent cobbles
Reaction: pH 6.1 to 7.3
Bt horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: sandy clay loam, loam or clay loam
Clay content: 20 to 35 percent
Rock fragments: 5 to 30 percent--5 to 25 percent gravel, 0 to 10 percent cobbles
Reaction: pH 6.6 to 7.8
Btk horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: sandy clay loam, loam or clay loam
Clay content: 20 to 35 percent
Calcium carbonate equivalent: 1 to 10 percent
Rock fragments: 5 to 30 percent--5 to 25 percent gravel, 0 to 10 percent cobbles
Reaction: pH 7.9 to 8.4
Bk horizon
Value: 6 or 7 dry; 5 or 6 moist
Chroma: 2 to 4; dry or moist
Texture: sandy clay loam, loam or clay loam
Clay content: 20 to 35 percent
Calcium carbonate equivalent: 5 to 14 percent
Rock fragments: 5 to 35 percent--5 to 25 percent gravel, 0 to 15 percent cobbles
Reaction: pH 7.9 to 8.4
BCk horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: sandy clay loam, loam or clay loam
Clay content: 20 to 35 percent
Calcium carbonate equivalent: 5 to 14 percent
Rock fragments: 35 to 60 percent--20 to 55 percent gravel, 0 to 15 percent cobbles
Reaction: pH 7.9 to 8.4
COMPETING SERIES:
Bondoe (MT) - is very deep
Bonfri (MT) - do not have a lithic contact
Fattig (MT) - have a lithologic discontinuity
Ferball (MT) - is very deep
Foreleft (MT) - is very deep
Raghorn (MT) - is very deep
.
GEOGRAPHIC SETTING:
Landform - hills
Elevation - 1830 to 2010 meters
Slope - 4 to 35 percent
Parent material - colluvium and residuum derived from interbedded shale, siltstone and sandstone
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 250 to 360 mm
Mean annual air temperature - 4 to 7 degrees C.
Frost-free period - 70 to 90 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Chinatown soils are used mainly for rangeland. The vegetation is mainly big sagebrush, rubber rabbitbrush, bluebunch wheatgrass, Poa (species), and miscellaneous forbs.
DISTRIBUTION AND EXTENT: Chinatown soils are of small extent in southwestern Montana. MLRAs - 43B, 44B.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Horse Prairie-South Valley Area - Part of Beaverhead County, Montana, 2011; proposed in Beaverhead County, Montana, 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 8 cm (A horizon)
Argillic horizon - from 8 to 36 cm (Bt and Btk horizons)
Horizons of secondary calcium carbonate accumulation - from 23 to 71 cm (Btk, Bk and BCk horizons)
Particle-size control section - from 8 to 36 cm (Bt and BtK horizons)
Chinatown soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
Taxonomic version: Tenth Edition, 2006
National Cooperative Soil Survey
U.S.A.