LOCATION BINVAR MT
Established Series
Rev. JAL/EMM
07/2012
BINVAR SERIES
The Binvar series consists of very deep, poorly drained soils that formed in alluvium and have extremely gravelly loamy sand at depths of 20 to 40 inches. These soils are on flood plains, alluvial fans, and low stream terraces. Slopes are 0 to 2 percent. Mean annual precipitation is about 16 inches, and the mean annual temperature is about 43 degrees F.
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Aeric Calciaquolls
TYPICAL PEDON: Binvar cobbly loam, in grassland (colors are for moist soil unless otherwise noted).
Oi--0 inch to 0.5 inch; undecomposed root mat.
A--0.5 to 7 inches; very dark grayish brown (10YR 3/2) cobbly loam, grayish brown (10YR 5/2) dry; moderate very fine granular structure; soft, very friable, slightly sticky and slightly plastic; many fine and very fine roots; 10 percent cobbles and 5 percent gravel; strongly effervescent; moderately alkaline (pH 8.0); clear smooth boundary. (4 to 8 inches thick)
Bk1--7 to 13 inches; brown (10YR 5/3) loam, very pale brown (10YR 7/3) dry; weak medium prismatic structure parting to weak medium and fine subangular blocky; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots; many very fine tubular and interstitial pores; 10 percent gravel; continuous distinct lime casts on undersides of gravel; disseminated lime; common fine masses of lime; violently effervescent; moderately alkaline (pH 8.4); gradual smooth boundary.
Bk2--13 to 21 inches; pale brown (10YR 6/3) loam, white (10YR 8/2) dry; weak medium and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots; many very fine tubular and interstitial pores; 10 percent gravel; disseminated lime and many masses; continuous distinct coating of lime on gravel; violently effervescent; moderately alkaline (pH 8.4); gradual smooth boundary. (combined thickness Bk horizons is 8 to 18 inches)
2Bk3--21 to 25 inches; very pale brown (10YR 7/3) very gravelly loam, white (10YR 8/2) dry; weak medium and fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots; many very fine tubular and interstitial pores; 40 percent gravel and 10 percent cobbles; disseminated lime; many fine masses of lime; continuous distinct coating of lime on gravel and cobbles; violently effervescent; moderately alkaline (pH 8.4); gradual smooth boundary. (0 to 6 inches thick)
2Bk4--25 to 37 inches; very pale brown (10YR 7/3) extremely gravelly sandy loam, white (10YR 8/2) dry; massive; soft, very friable, slightly sticky and nonplastic; 45 percent gravel and 20 percent cobbles; disseminated lime; many fine masses of lime; violently effervescent; moderately alkaline (pH 8.4); gradual smooth boundary. (combined thickness of 2Bk horizons is 8 to 20 inches)
3C--37 to 60 inches; dark brown (10YR 4/3) extremely gravelly loamy sand, pale brown (10YR 6/3) dry; single grain; loose, nonsticky and nonplastic; 50 percent gravel and 15 percent cobbles; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Lewis and Clark County, Montana; 500 feet west and 30 feet south of the NE corner of sec. 23, T. 20 N., R. 6 W.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Moisture control section - between 4 and 12 inches.
Mollic epipedon thickness - 7 to 16 inches.
Depth to 3C horizon - 20 to 40 inches.
Depth to water table - 12 to 24 inches.
Some pedons have faint or prominent redox concentrations with hue of 5YR or 7.5YR and value of 4 or 5 and chroma of 6 or 8 above the 3C horizon.
A horizon
Hue: 10YR or 2.5Y
Value: 2 or 3 moist, 4 or 5 dry
Chroma: 1 or 2
Clay content: 18 to 25 percent clay
Rock fragments: 15 to 35 percent--10 to 20 percent cobbles, 5 to 15 percent gravel
Reaction: pH 7.4 to 8.4
Bk horizons
Hue: 10YR or 2.5YR
Value: 4, 5, or 6 moist, 5, 6, or 7 dry
Chroma: 2, 3, or 4
Clay content: 18 to 25 percent
Rock fragments: 5 to 15 percent--0 to 5 percent cobbles, 5 to 10 percent gravel
Calcium carbonate equivalent: 20 to 30 percent
Reaction: pH 7.9 to 8.4
2Bk horizons
Hue 10YR or 2.5YR
Value: 5 or 6 moist, 7 or 8 dry
Chroma: 2 or 3
Texture: loam or sandy loam
Clay content: 10 to 15 percent
Rock fragments: 50 to 75 percent--10 to 20 percent cobbles, 30 to 55 percent gravel
Calcium carbonate equivalent: 20 to 30 percent
Reaction: pH 7.9 to 8.4
3C horizon
Hue: 10YR or 2.5Y
Value: 4, 5, or 6 moist, 5, 6, or 7 dry
Chroma: 3 or 4
Texture: loamy sand or sand
Clay content: 0 to 5 percent
Rock fragments: 60 to 80 percent--10 to 20 percent cobbles, 50 to 60 percent gravel
Calcium carbonate equivalent: 5 to 10 percent
Reaction: pH 7.4 to 8.4
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Landform - flood plains and low stream terraces.
Elevation - 3,500 to 4,500 feet.
Slope - 0 to 2 percent.
Parent material - alluvium.
Climate - long, cold winters; moist springs; warm summers.
Mean annual precipitation - 12 to 19 inches, most of which falls as rain or snow in late fall through late spring and into early summer.
Mean annual temperature - 40 to 45 degrees F.
Frost-free period - 80 to 120 days.
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Poorly drained, moderate permeability above the 3C horizon and rapid in the 3C. These soils are rarely flooded.
USE AND VEGETATION: Binvar soils are used for irrigated and nonirrigated grass hay and for rangeland. The potential native vegetation is mainly tall reedgrass, managrass, tufted hairgrass, forbs, sedges, and shrubs.
DISTRIBUTION AND EXTENT: Binvar soils are of limited extent in the intermountain valleys of western Montana. MLRAs 44B and 46.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Lewis and Clark County Area, Montana, 1991; proposed in Lewis and Clark County, Montana 1989.
REMARKS: Soil interpretation records: MT1232.
Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 7 inches (mixed)(A, Bk1 horizons)
Calcic horizons - from 7 to 37 inches (Bk1, 2Bk2, 2Bk3, 2Bk4)
Lithological discontinuity - extremely gravelly loamy sand from 37 to 60 inches (3C horizon)
Particle size control section -from 10 to 40 inches (part of the Bk1,the 2Bk2, 2Bk3, 2Bk4, and part of the 3C horizon).
Binvar soils have a frigid temperature and an aquic moisture regime.
The Binvar series should be evaluated to fix the discrepancies in the Munsell color code vs. the true names.
National Cooperative Soil Survey
U.S.A.