LOCATION BARVON MTEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Entic Haplustolls
TYPICAL PEDON: Barvon loam, woodland. (Colors are for dry soil unless otherwise noted)
Oi--0 to 0.5 inch; pine needles, grass, twigs and leaves.
Oe--0.5 to 0.75 inch; decomposed pine needles, grasses and leaves mixed with mineral soil (Combined O horizons 0 to 2 inches thick)
A1--0.75 to 4.75 inches; dark grayish brown (10YR 4/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine granular structure; soft, friable, slightly sticky and nonplastic; many very fine roots; many krotovinas; soil mass noncalcareous, but some pebbles lime-coated on lower sides; less than 1 percent pebbles; neutral (pH 7.0); clear smooth boundary.
A2--4.75 to 14.75 inches; grayish brown (10YR 5/2) and brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; soft, very friable, sticky and slightly plastic; common very fine roots; many very fine and common fine tubular pores; many large krotovinas; few fine masses of lime; slightly effervescent; some pebbles lime coated on lower sides; less than 1 percent pebbles; slightly alkaline (pH 7.6); clear wavy boundary. (Combined A horizons 7 to 16 inches thick)
Bk1--14.75 to 24.75 inches; pale brown (10YR 6/3) light clay loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, sticky and plastic; few very fine and medium roots; common fine and medium tubular pores; many large krotovinas; strongly effervescent; common seams and threads of segregated lime; moderately alkaline (pH 8.2); gradual wavy boundary.
Bk2--24.75 to 34.75 inches; light yellowish brown (2.5Y 6/4) clay loam, light olive brown (2.5Y 5/4) moist; massive; slightly hard, friable, sticky and slightly plastic; few very fine roots; common fine and medium tubular pores; strongly effervescent; common seams and threads of segregated lime; moderately alkaline (pH 8.2); gradual wavy boundary. (Combined Bk horizons 12 to 24 inches thick)
Cr1--34.75 to 42.75 inches; light gray (5Y 7/2) weakly consolidated sandy sedimentary beds, light olive gray (5Y 6/2) moist; few very fine roots along fracture planes; strongly effervescent; moderately alkaline (pH 8.2); clear boundary.
Cr2--42.75 to 60 inches; stratified weakly consolidated silty sedimentary beds and semi-consolidated shale.
TYPE LOCATION: Powder River County, Montana; NE 1/4 of sec. 17, T. 3 S., R. 47 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 47 degrees F.
Mollic epipedon thickness - 7 to 16 inches.
Control section - 20 to 30 percent clay and 0 to 10 percent flat angular pebbles.
Depth to bedrock - 20 to 40 inches.
Depth to K horizon - 7 to 16 inches.
A horizon:
Hue: 10YR
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3
Texture, less than 2 mm: loam or silt loam
Clay content: 20 to 27 percent
Rock fragments: 0 to 5 percent pebbles
Reaction: pH 6.6 to 7.8
Some pedons have a light colored Bw horizon in place of the A2 horizon. When present it extends to a depth of less than 10 inches.
Bk horizons:
Hue: 10YR or 2.5Y
Value: 5 to 7 dry; 4 to 6 moist
Chroma: 2 to 4
Texture, less than 2 mm: loam or clay loam
Clay content: 20 to 30 percent
Rock fragments: 0 to 10 percent flat angular pebbles
Calcium Carbonate Equivalent: 5 to 15 percent
Reaction: pH 7.4 to 8.4
Cr horizon:
Hue: 10YR, 2.5Y or 5Y
Value: 6 to 8 dry; 5 or 6 moist
Chroma: 2 to 6
Texture, less than 2 mm: weakly consolidated sandy or silty sedimentary beds or semi-consolidated shale that texture to loamy fine sand to light silty clay
COMPETING SERIES: There are the
Coulterg,
Mavreeso and
Rottulee series.
Coulterg: do not have a paralithic contact at depths of 20 to 40 inches.
Mavreeso: have hue of 7.5YR or redder.
Rottulee: have limestone bedrock at 20 to 40 inches.
GEOGRAPHIC SETTING:
Landform - sedimentary plains and hills.
Elevation - 2,300 to 4,500 feet.
Slope- 2 to 70 percent.
Parent material - residuum derived from weakly consolidated sandy and silty sedimentary beds and semiconsolidated shale.
Climate - long, cold winters; moist springs; and warm summers.
Mean annual precipitation - 12 to 20 inches.
Mean annual air temperature - 40 to 45 degrees F.
Frost-free period - 100 to 135 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arnegard, Bitton, Cabba, Campspass, Farland, Lamedeer and Ringling soils. Arnegard soils occur at the base of slopes or in beds of drainage valleys and have a mollic epipedon 20 inches or more thick. Bitton and Lamedeer sils have a loamy-skeletal particle-size control section and lack a Cr horizon. Cabba soils lack a mollic epipedon and have weakly consolidated sedimentary beds at depths of less than 20 inches. Campspass soils have an argillic horizon with more than 35 percent clay. Farland soils lack a Cr horizon and have an argillic horizon. Ringling soils have fragmental material at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: Barvon soils are used mainly for woodland. Potential native vegetation is mainly ponderosa pine with a canopy cover of 30 to 50 percent. The understory is mainly bluebunch wheatgrass, Idaho fescue, common snowberry, common chokecherry and Oregon-grape.
DISTRIBUTION AND EXTENT: Barvon soils are of moderate extent in southeastern Montana.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Powder River County (Powder River Area), Montana, 1972.
REMARKS: Soil Interpretations Record: MT0260, MT1135.
Diagnostic horizons and features recognized in this pedon are: mollic epipedon - from the mineral soil surface to 14 inches (A1 and A2 horizons); horizons of secondary carbonate accumulation - from 143/4 to 343/4 inches (Bk1 and Bk2 horizons); a paralithic contact at 343/4 inches (Cr horizon); particle-size control section - from 103/4 to 343/4 inches.