LOCATION CHECKERBOARD MT

Tentative Series
Rev. SPV/EMM
07/2012

CHECKERBOARD SERIES

The Checkerboard series consists of shallow, well drained soils that formed in residuum and colluvium derived from limestone and dolomite. Checkerboard soils are on ridges, mountains and hills. Slopes are 2 to 75 percent. The mean annual precipitation is about 480 mm and the mean annual temperature is about 3 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, carbonatic Lithic Calcicryolls

TYPICAL PEDON: Checkerboard very gravelly silt loam--rangeland. (Colors are for dry soil unless otherwise noted).

A1--0 to 12 cm; dark gray (10YR 4/1) very gravelly silt loam, very dark gray (10YR 3/1) moist; weak very fine and fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine irregular pores; 35 percent gravel; 25 percent carbonate coating around rock fragments; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary.

A2--12 to 28 cm; dark grayish brown (10YR 4/2) very gravelly silt loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine irregular pores; 35 percent gravel and 5 percent cobbles; 60 percent carbonate coating around rock fragments; strongly effervescent; moderately alkaline (pH 8.0); clear wavy boundary. (combined thickness of the A horizon is 18 to 28 cm)

Bk--28 to 47 cm; grayish brown (10YR 5/2) extremely gravelly silt loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine and fine roots; common very fine irregular pores; 50 percent gravel and 10 percent cobbles; 60 percent secondary carbonate coating on bottom of rock fragments; violently effervescent; moderately alkaline (pH 8.2); abrupt wavy boundary. (10 to 27 cm thick)

R--47 cm; hard fractured limestone.

TYPE LOCATION: Meagher County, Montana; about 5 miles southwest of the village of Checkerboard; 1,630 feet west and 730 feet south of the northeast corner of section 34, T. 9N., R9E; Checkerboard topographic quadrangle, MT; UTM 12T 0532745E, 5149987N, NAD 83.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature: 1 to 4 degrees C.
Mollic epipedon thickness: 18 to 50 cm
Depth to bedrock: 25 to 50 cm to a lithic contact
Depth to calcic horizon: 10 to 28 cm
Particle-size control section - Clay content: 15 to 27 percent
Rock fragments: average 35 to 75 percent in the particle-size control section, mainly limestone or dolomite gravel.

A1 horizon
Hue: 10YR or 7.5 YR dry or moist
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3, dry or moist
Texture: loam or silt loam
Clay content: 15 to 27 percent
Rock Fragments: 20 to 45 percent--0 to 15 cobbles and stones, 10 to 35 percent gravel
Calcium Carbonate Equivalent: 3 to 15 percent, including coarse fragments less than the 20 mm fraction.
Reaction: pH 7.7 to 8.0

A2 horizon (where present)
Hue: 10YR or 7.5 YR dry or moist
Value: 3 to 5 dry; 2 or 3 moist
Chroma: 1 to 3, dry or moist
Texture: loam or silt loam
Clay content: 15 to 27 percent
Rock Fragments: 40 to 70 percent--0 to 25 percent cobbles and stones, 40 to 60 percent gravel
Calcium Carbonate Equivalent: 15 to 40 percent, including coarse fragments less than the 20 mm fraction.
Reaction: pH 8.0 to 8.2

Bk horizon
Hue: 10YR or 7.5 YR, dry or moist
Value: 4 to 6 dry; 2 to 4 moist
Chroma: 2 or 3, dry or moist
Texture: loam or silt loam
Clay content: 15 to 27 percent
Rock Fragments: 40 to 75 percent--15 to 30 percent cobbles and stones, 15 to 45 percent gravel
Calcium Carbonate Equivalent: 40 to 60 percent, including coarse fragments less than the 20 mm fraction.
Reaction: pH 8.0 to 8.4

COMPETING SERIES: These are the Adobe and Jimbee soils.
Adobe (NV)- has a xeric soil moisture regime
Jimbee (ID)- has Bkq horizons

GEOGRAPHIC SETTING:
Landform - ridges, hills and mountain slopes
Elevation - 1,450 to 2,425 meters
Slope - 2 to 75 percent
Parent Material - colluvium over residuum from limestone and dolomite
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 380 to 610 mm
Mean annual air temperature - 1 to 4 degrees F
Frost-free period - 30 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Farlin and Hardhart soils. Farlin soils occur in concave positions, are very deep and have a neutral surface horizon. Hardhart soils are on linear slope positions and are moderately deep to a lithic contact.

DRAINAGE AND PERMEABILITY: Well drained; high surface runoff; moderate permeability.

USE AND VEGETATION: Checkerboard soils are used for rangeland and wildlife habitat. Native vegetation is mainly blue bunch wheatgrass, Idaho fescue, Cussick's bluegrass, prairie Junegrass, phlox, western yarrow, vetch, and arrowleaf balsamroot. Checkerboard may support a scattered overstory of Douglas-fir, ponderosa pine, limber pine, and Rocky Mountain juniper.

DISTRIBUTION AND EXTENT: Western and Central Montana. These soils are moderately extensive. MLRAs 46 and 43B.

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

SERIES PROPOSED: Meagher County, Montana, 2010. Checkerboard is named after the village of Checkerboard.

REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 28 cm (A1 and A2 horizons).
Calcic horizon - The zone from 28 to 47 cm (Bk horizon).
Lithic contact - The boundary at 47 cm to underlying hard bedrock (R horizon).
Particle-size control section - The zone from 25 to 47 cm (part of the A2 horizon and the Bk horizon).

Taxonomic version: Eleventh Edition: 2010

National Cooperative Soil Survey
U.S.A.