LOCATION BOATMAN MT

Established Series
Rev. KTS-RJS
01/2012

BOATMAN SERIES

The Boatman series consists of very deep, well drained soils that formed in colluvium derived from sedimentary, metamorphic, or igneous rock sources. Boatman soils are on fan remnants, escarpments and mountain slopes. Slopes range from 15 to 80 percent. Mean annual precipitation is about 710 mm and the mean annual temperature is about 3 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Pachic Haplocryolls

TYPICAL PEDON: Boatman very gravelly loam on a 75 percent north facing slope at about 2195 meters elevation. (Colors are for air-dry soil unless otherwise stated.)

Oi--0 to 7 cm; slightly decomposed forest litter; clear smooth boundary. (0 to 8 cm thick)

A--7 to 23 cm; dark grayish brown (10YR 4/2) very gravelly loam, very dark brown (10YR 2/2) moist; weak, fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; many very fine and fine irregular pores; 40 percent gravel and less than 1 percent cobbles; neutral (pH 6.6); clear smooth boundary. (14 to 25 cm thick)

Bw1--23 to 44 cm; dark grayish brown (10YR 4/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure parting to moderate medium and fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine, fine, and medium roots; many very fine and fine irregular pores; 40 percent gravel and 10 percent cobbles; slightly acid (pH 6.4); clear wavy boundary.

Bw2--44 to 87 cm; brown (10YR 4/3) very gravelly sandy clay loam, dark brown (10YR 3/3) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine irregular pores; 35 percent gravel, 10 percent cobbles and 5 percent stones; neutral (pH 6.6); gradual wavy boundary. (combined thickness of the Bw horizons - 40 to 100 cm)

BC--87 to 152 cm; grayish brown (10YR 5/2) extremely gravelly sandy loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine and fine irregular pores; 45 percent gravel, 15 percent cobbles and 5 percent stones; neutral (pH 7.2).

TYPE LOCATION: Beaverhead County, Montana; located about 650 meters south and 25 meters west of the northeast corner of sec. 28, T. 14 S., R 1 W; Upper Red Rock Lake topographic quadrangle; UTM 12T, 442814e., 4937220n. NAD 83.

RANGE IN CHARACTERISTICS:
Mean Annual Soil Temperature: 2 to 5 degrees C
Thickness of the mollic epipedon: 40 cm or greater
Particle-size control section: averages 18 to 27 percent clay
Note: Some pedons have a C horizon

A horizons:
Hue: 7.5YR or 10YR; dry or moist
Value: 3 or 4 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam or loam
Clay content: 16 to 24 percent
Rock fragments: 15 to 45 percent--10 to 45 percent gravel, 0 to 10 percent cobbles and stones
Reaction: pH 5.6 to 6.8

Bw horizons:
Hue: 7.5YR or 10YR; dry or moist
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam, sandy clay loam or loam
Clay content: 18 to 27 percent
Rock fragments: 35 to 70 percent--25 to 60 percent gravel, 5 to 20 percent cobbles and stones
Reaction: pH 5.6 to 6.8

BC horizon:
Hue: 7.5YR or 10YR; dry or moist
Value: 4 to 6 dry; 3 to 5 moist
Chroma: 2 or 3; dry or moist
Texture: sandy loam, sandy clay loam or loam
Clay content: 18 to 27 percent
Rock fragments: 35 to 70 percent--25 to 60 percent gravel, 10 to 25 percent cobbles and stones
Reaction: pH 6.0 to 7.4

COMPETING SERIES:
Baconcamp (OR) - has a lithic contact at depths of less than 100 cm
Badgerton (ID) - has a xeric moisture regime
Badhap (NV) - has a xeric moisture regime
Behanco (CO) - has a lithic contact at depths of less than 150 cm
Behanin (UT) - has clay films in the Bw horizons
Belsac (NV) - has a paralithic contact at depths of less than 100 cm
Boydhollow (ID) - has a xeric moisture regime
Bullrey (ID) - has an ustic moisture regime
Busterback (ID) - has a xeric moisture regime
Croesus (NV) - has a xeric moisture regime
Dressel (CO) - timing of precipitation; peak periods occur during July and August and the least amount occurs during May and June
Gateview (CO) - timing of precipitation; peak periods occur during the winter and the least amount occurs during May and June
Goodski (NV) - has a lithic contact at depths of less than 100 cm
Hapgood (NV) - has a xeric moisture regime
Harcany (NV) - has a xeric moisture regime
Hobacker (WY) - has secondary calcium carbonates
Lionhead (ID) - has secondary calcium carbonates
Lolon (MT) - has an ustic moisture regime
Marcetta (MT) - has an ustic moisture regime
Mundos (WY) - has secondary calcium carbonates
Nagitsy (ID) - has a lithic contact at depths of less than 100 cm
Namela (CO) - has a lithic contact at depths of less than 100 cm
Nazaton (ID) - has a cambic horizon
Papaspila (CO) - timing of precipitation; peak periods occur during July and August and the least amount occurs during May and June
Parkcity (UT) - averages less than 18 percent clay in the particle size control section
Poleline (UT) - has a lithic contact at depths of less than 100 cm
Povey (ID) - has a xeric moisture regime
Snacreek (NV) - has a xeric moisture regime
Snopoc (NV) - has a xeric moisture regime
Splitbutte (ID) - has a lithic contact at depths of less than 100 cm
Sweethollow (ID) - has 12 to 16 percent clay in the particle size control section
Tonigut (UT) - has secondary calcium carbonates

GEOGRAPHIC SETTING:
Landform - fan remnants, escarpments and mountain slopes
Elevation - 2130 to 2930 meters
Slope - 15 to 80 percent
Parent material - colluvium derived from sedimentary, metamorphic, or igneous rock sources
Climate - long, cold winters; moist springs; short warm summers.
Mean annual precipitation - 600 to 920 mm
Mean annual air temperature - 1 to 4 degrees C
Frost-free period - 30 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.

USE AND VEGETATION: These soils are used mainly for recreation and wildlife. The vegetation is mainly subalpine fir, whitebark pine, POA (species), mountain big sagebrush, columbine, lupine, yarrow, buckwheat, and other miscellaneous grasses and forbs. Forest canopy cover is typically less than 25 percent.

DISTRIBUTION AND EXTENT: Boatman soils are of limited extent in southwestern Montana. MLRA 43B.

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, 2011.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 7 to 87 cm. (A, Bw1 and Bw2 horizons); and a
Particle-size control section - from 32 to 107 cm (part of the Bw1, Bw2 and part of the BC horizons).

Boatman soils have a cryic temperature regime and a udic moisture regime.

Taxonomic version: Eleventh Edition, 2010.

National Cooperative Soil Survey
U.S.A.