LOCATION TRAILHOLLOW             MT

Established Series
Rev. GFB-RJS
01/2012

TRAILHOLLOW SERIES


The Trailhollow series consists of very deep, well drained soils that formed in alluvium derived from mixed rock sources. Trailhollow soils are on stream terraces, alluvial fans and drainageways. Slopes are 0 to 15 percent. The mean annual precipitation is about 400 mm, and the mean annual air temperature is about 3 degrees C.

TAXONOMIC CLASS: Fine-loamy, mixed, superactive Ustic Haplocryolls

TYPICAL PEDON: Trailhollow loam, in rangeland on a 3 percent slope at about an elevation of 2,121 meters. (colors are for air-dry soil unless otherwise stated.)

A--0 to 15 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine and few fine roots; many very fine and fine dendritic tubular pores; neutral (pH 6.6); clear smooth boundary. (10 to 20 cm thick)

Bw--15 to 28 cm; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine and fine dendritic tubular pores; finely disseminated calcium carbonate; slightly alkaline (pH 7.8); clear wavy boundary. (8 to 20 cm thick)

BCk1--28 to 107 cm; pale brown (10YR 6/3), gravelly loam, brown (10YR 5/3) moist; massive; hard, very friable, moderately sticky and slightly plastic; few very fine roots; common very fine irregular pores; 15 percent gravel; 10 percent fine and medium soft masses of calcium carbonate, 50 percent distinct continuous calcium carbonate coatings on coarse fragments, and finely disseminated calcium carbonate; violently effervescent; moderately alkaline (pH 8.2). (64 to 90 cm thick)

BCk2--107 to 152 cm; brown (10YR 5/3), clay loam, brown (10YR 4/3) moist; massive; very hard, friable, moderately sticky and slightly plastic; few very fine roots; common very fine irregular pores; 10 percent fine and medium soft masses of calcium carbonate, and finely disseminated calcium carbonate; strongly effervescent; moderately alkaline (pH 8.2).

TYPE LOCATION: Beaverhead County, Montana; located about 396 meters south and 792 meters east of the northwest corner of sec.18, T. 13S, R. 10 W; Dixon Mountain topographic quadrangle; UTM 12T, 352296e, 4951966n, NAD 83.

RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 2 to 5 degrees C.
Mollic epipedon thickness - 18 to 30 cm
Depth to secondary calcium carbonate - 18 to 40 cm

A horizon
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3; dry or moist
Clay content: 18 to 24 percent
Rock fragments: 0 to 10 percent--0 to 10 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 0 to 1 percent
Reaction: pH 6.6 to 7.6

Bw horizon
Value: 5 or 6 dry; 3 or 4 moist
Chroma: 2 or 3; dry or moist
Clay content: 18 to 27 percent
Rock fragments: 0 to 10 percent--0 to 10 percent gravel, 0 to 5 percent cobbles
Calcium carbonate equivalent: 0 to 3 percent
Reaction: pH 7.4 to 7.9

BCk1, BCk2 horizons
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 3 or 4; dry or moist
Texture: loam or clay loam
Clay content: 18 to 35 percent
Rock fragments: 0 to 20 percent--0 to 20 percent gravel, 0 to 5 percent cobbles
0 to 20 percent gravel and cobbles
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 8.4

COMPETING SERIES:
Auzqui (WY) - do not have secondary calcium carbonate accumulation
Bynum (MT) - are moderately deep to paralithic contact
Emerald (CO) - do not have secondary calcium carbonate accumulation
Lymaning (CO) - are moderately deep to paralithic contact
Redcloud (CO) - have a horizon with greater than 15 percent exchangeable sodium
Tamp (CO) - do not have secondary calcium carbonate accumulation
Tampico (NM) - do not have secondary calcium carbonate accumulation
Teton (MT) - are moderately deep to lithic contact
Thayne (WY) - have a loamy-skeletal layer within the series control section
Tilton (CO) - do not have a BCk horizon.
Uhl (WY) - do not have secondary calcium carbonate accumulation
Wrenman (WY) - are moderately deep to lithic contact

GEOGRAPHIC SETTING:
Landform - stream terraces, alluvial fans and drainageways
Elevation - 1,980 to 2,250 meters
Slope - 0 to 15 percent
Parent material - formed in alluvium derived from mixed rock sources
Climate - long, cold winters; moist springs; short warm summers
Mean annual precipitation - 380 to 510 mm
Mean annual air temperature - 1 to 4 degrees C.
Frost-free period - 50 to 70 days

GEOGRAPHICALLY ASSOCIATED SOILS: None listed.

DRAINAGE AND PERMEABILITY: Well drained, moderate permeability.

USE AND VEGETATION: These soils are used for rangeland. Potential vegetation consists of sagebrush, western wheatgrass, basin wildrye, and bluegrass.

DISTRIBUTION AND EXTENT: The series is of small extent in southwestern Montana. MLRAs - 43B, 44B.

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 0 to 28 cm (A, Bw horizons)
Secondary calcium carbonate accumulation - from 28 to 152 cm (BCk1, BCk2 horizons)
Particle-size control section - from 25 to 100 cm (part of Bw, part of BCk1 horizons)

Trailhollow soils have a cryic temperature regime and an ustic moisture regime.

Taxonomic version: Eleventh Edition, 2010.


National Cooperative Soil Survey
U.S.A.