LOCATION LEHUNT MT

Established Series
Rev: GFB-KTS-RJS
03/2012

LEHUNT SERIES

The Lehunt series consists of very deep, somewhat poorly drained soils that formed in alluvium or lacustrine deposits. These soils occur on stream terraces and lakebeds. These soils are subject to prolonged saturation from flood irrigation. Slopes are 0 to 2 percent. Mean annual precipitation is about 15 inches, and mean annual air temperature is about 37 degrees F.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive Oxyaquic Haplocryalfs

TYPICAL PEDON: Lehunt fine sandy loam, in irrigated grass hay and pasture (colors are for dry soil unless otherwise noted).

A--0 to 3 inches; dark grayish brown (10YR 4/2) fine sandy loam, very dark brown (10YR 2/2) moist; weak fine and medium granular structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and fine dendritic tubular pores; moderately alkaline (pH 8.2); abrupt smooth boundary. (0 to 4 inches thick)

E--3 to 7 inches; light brownish gray (10YR 6/2) fine sandy loam, dark grayish brown (10YR 4/2) moist; moderate very coarse angular blocky structure; hard, friable, nonsticky and nonplastic; many very fine and fine roots; many very fine and common fine dendritic tubular pores; very strongly alkaline (pH 9.8); abrupt smooth boundary. (3 to 12 inches thick)

Btn--7 to 11 inches; brown (10YR 5/3) sandy clay, dark brown (10YR 3/3) moist; strong medium and coarse columnar structure; extremely hard, firm, moderately sticky and moderately plastic; common very fine roots; common very fine and few fine dendritic tubular pores; many continuous prominent very dark gray (10YR 3/1) clay films on faces of peds; very strongly alkaline (pH 10.0); clear smooth boundary. (4 to 8 inches thick)

Btkn--11 to 15 inches; pale brown (10YR 6/3) loam, brown (10YR 5/3) moist; moderate very coarse prismatic structure; extremely hard, firm, very sticky and very plastic; few very fine roots; common very fine and few fine dendritic tubular pores; many continuous distinct clay films on faces of peds; strongly effervescent; finely disseminated calcium carbonate and many medium and fine patchy soft masses and threads of calcium carbonate; very strongly alkaline (pH 10.3); clear wavy boundary. (4 to 10 inches thick)

BCn1--15 to 32 inches; pale brown (10YR 6/3) sandy loam, yellowish brown (10YR 5/4) moist; weak coarse and very coarse prismatic structure; hard, friable, slightly sticky and nonplastic; few very fine roots; common very fine dendritic tubular pores; slightly effervescent; very strongly alkaline (pH 10.3); clear wavy boundary.

BCn2--32 to 40 inches; light yellowish brown (10YR 6/4) sandy clay loam, brown (10YR 5/3) moist; weak medium and coarse subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine roots; few very fine dendritic tubular pores; few medium prominent irregular, strong brown (7.5YR 5/6) masses of oxidized iron; very strongly alkaline (pH 9.8); clear wavy boundary. (combined thickness of BCn horizons - 20 to 30 inches)

2C--40 to 60 inches; pale brown (10YR 6/3) extremely gravelly sand, grayish brown (10YR 5/2) moist; single grain; loose, nonsticky and nonplastic; 65 percent gravel; slightly alkaline (pH 7.5).

TYPE LOCATION: Beaverhead County, Montana; approximately 1500 feet north and 1800 feet west of the SE corner of sec. 4, T. 3S, R. 15W, Wisdom topographic quadrangle, NAD 83, UTM 12T, 308144e, 5042729n.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 35 to 40 degrees F.
Depth to top of natric horizon - 4 to 16 inches
Depth to seasonal high water table - 24 to 42 inches.
Depth to lithologic discontinuity - 40 to 60 inches
Soil phases - saline

Note: A thin (less than 3 inches) Oe horizon may be present.

A horizon
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 12 to 20 percent
Texture: fine sandy loam or loam
Rock fragments: 0 to 15 percent gravel
Reaction: pH 7.4 to 8.4
Electrical conductivity: 0 to 3 mmhos/cm
Sodium adsorption ratio: 13 to 30

E horizon
Value: 6 or 7 dry; 4 or 5 moist
Chroma: 2 or 3; dry or moist
Texture: fine sandy loam, sandy loam or loam
Clay content: 5 to 15 percent
Reaction: pH 8.5 to 10.0
Electrical conductivity: 0 to 4 mmhos/cm
Sodium adsorption ratio: 13 to 40

Saline phase
Reaction: pH 9.5 to 11.0
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 40 to 100

Btn horizon
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3; dry or moist
Texture: sandy clay, clay loam or sandy clay loam
Clay content: 27 to 40 percent
Reaction: pH 9.0 to 10.5
Electrical conductivity: 4 to 8 mmhos/cm
Sodium adsorption ratio: 40 to 100

Btkn horizon
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 or 3; dry or moist
Texture: loam, clay loam or sandy clay loam
Clay content: 25 to 35 percent
Calcium carbonate equivalent: 1 to 10 percent
Reaction: pH 9.0 to 10.5
Electrical conductivity: 4 to 8 mmhos/cm
Sodium adsorption ratio: 40 to 100

BCn1, BCn2 horizons
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 2 to 4; dry or moist
Texture: sandy loam, loam or sandy clay loam
Clay content: 15 to 25 percent
Rock fragments: 0 to 15 percent gravel
Calcium carbonate equivalent: 0 to 1 percent
Reaction: pH 8.5 to 10.5
Electrical conductivity: 1 to 4 mmhos/cm
Sodium adsorption ratio: 40 to 100

2C horizon
Chroma: 1 to 3; dry or moist
Texture: sand or loamy sand
Clay content: 1 to 6 percent
Rock fragments: 35 to 80 percent gravel
Reaction: pH 6.6 to 7.8

COMPETING SERIES: There are no competing series.

GEOGRAPHIC SETTING:
Landform - stream terraces and lakebeds
Elevation - 5900 to 7,400 feet
Slope - 0 to 2 percent
Parent material - alluvium or lacustrine deposits
Climate - long, cold winters; cool, moist springs; short, cool summers
Mean annual precipitation - 14 to 19 inches
Mean annual air temperature - 34 to 39 degrees F.
Frost-free period - 30 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bighole, Shewag and Wisdom soils. Bighole soils are not salt and sodium effected and are on similar landforms. Shewag soils are sandy-skeletal and are on outwash plains. Wisdom soils are fine-loamy over sandy or sandy-skeletal and are on outwash plains.

DRAINAGE AND PERMEABILITY: Somewhat poorly drained; moderately slow over very rapid permeability.

USE AND VEGETATION: Lehunt soils are used for irrigated grass hay and irrigated pasture. The vegetation is mainly basin wildrye, alkali cordgrass, alkali sacaton, western wheatgrass, inland saltgrass and greasewood.

DISTRIBUTION AND EXTENT: Lehunt soils are not extensive in the intermountain valleys of southwestern Montana. MLRA - 44B.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.

SERIES ESTABLISHED: Beaverhead County, Montana, Big Hole Valley Area, 2005.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - from 0 to 7 inches (A, E horizons)
Albic horizon - from 3 to 7 inches (E horizon)
Natric horizon - from 7 to 15 inches (Btn, Btkn horizons)
Lithologic discontinuity - at 40 inches (2C horizon)
Particle-size control section - from 7 to 15 inches (Btn, Btkn horizons)

Lehunt soils have a cryic temperature regime and an ustic moisture regime and an oxyaquic moisture subclass.

ADDITIONAL DATA: NSSL data S03MT-001-001

National Cooperative Soil Survey
U.S.A.