LOCATION LOSTTRAIL MT
Established Series
Rev. EMR/JMS/RJS
07/2013
LOSTTRAIL SERIES
The Losttrail series consists of very deep, somewhat excessively drained soils formed in alluvium from mixed sources. These soils are on alluvial fans, fan remnants, and stream terraces in intermountain valleys. Slopes are 0 to 25 percent. Mean annual precipitation is about 368 mm and mean annual temperature is about 6 degrees C.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Typic Haplustolls
TYPICAL PEDON: Losttrail loam, in rangeland on a 20 percent slope at 1,130 meters elevation (Colors are for dry soil unless otherwise indicated).
A--0 to 20 cm; dark grayish brown (10YR 4/2) loam, very dark brown (10YR 2/2) moist; moderate coarse granular structure; friable, slightly hard, slightly sticky, nonplastic; common very fine and fine roots; many very fine and fine tubular pores; 5 percent gravel; neutral (pH 6.8); clear smooth boundary. 18 to 30 cm thick)
Bw--20 to 51 cm; light yellowish brown (10YR 6/4) sandy loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; common very fine and fine roots; common fine tubular pores; 5 percent gravel; slightly alkaline (pH 7.4); gradual smooth boundary. (20 to 46 cm thick)
Bk--51 to 79 cm; light gray (10YR 7/2) sandy loam, dark grayish brown (10YR 4/2) moist; moderate medium subangular blocky structure; friable, slightly hard, nonsticky, nonplastic; common very fine and fine roots; common fine interstitial pores; 10 percent gravel; finely disseminated carbonates throughout; strongly effervescent, moderately alkaline (pH 8.1); gradual smooth boundary. (10 to 28 cm thick)
C1--79 to 124 cm; light gray (10YR 7/2) gravelly loamy sand, grayish brown (10YR 5/2) moist; single grain; loose, nonsticky, nonplastic; few fine roots; common fine interstitial pores; 20 percent gravel; very slightly effervescent; slightly alkaline (pH 7.8) gradual wavy boundary.
C2--124 to 152 cm; light gray (10YR 7/2) very gravelly sand, grayish brown (10YR 5/2) moist; single grain; loose, nonsticky, nonplastic; common fine interstitial pores; 40 percent gravel, 5 percent cobbles; neutral (pH 7.0).
TYPE LOCATION: Grayhorse Creek topographic quadrangle, Ravalli County, Montana; 370 meters north and 405 meters west of the SE corner section 10, T 9 N, R 19 W; UTM zone 12, 272547e, 5159175n, NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C
Mollic epipedon thickness - 18 to 30 cm
Depth to secondary calcium carbonate accumulation - 38 to 76 cm
Depth to sandy-skeletal material - 75 to 124 cm
A horizon
Value: 4 or 5 dry; 3 or 2 moist
Texture: loam or sandy loam
Clay content: 14 to 24 percent
Content of rock fragments: 0 to 15 percent-- 0 to 15 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.6 to 7.8
Bw horizon
Chroma: 2 to 4 dry or moist
Texture: sandy loam or loam
Clay content: 12 to 18 percent
Content of rock fragments: 0 to 15 percent--0 to 15 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.6 to 7.8
Bk horizon
Value: 7 dry; 4 or 5 moist
Texture: sandy loam or fine sandy loam
Clay content: 12 to 18 percent
Content of rock fragments: 0 to 35 percent--0 to 20 percent gravel, 0 to 10 percent cobbles
Calcium carbonate equivalent: 4 to 10 percent
Reaction: pH 7.9 to 8.2
C horizon(s)
Value: 6 or 7 dry; 4 or 5 moist
Texture: sand, loamy sand, loamy coarse sand
Clay content: 2 to 14 percent
Content of rock fragments: 15 to 60 percent--15 to 50 percent gravel, 0 to 15 percent cobbles
Calcium carbonate equivalent: 0 to 5 percent
Reaction: pH 6.6 to 8.0
COMPETING SERIES:
Baggs (MT) - do not have a horizon of secondary calcium carbonate accumulation; do not have more than 15 percent rock fragments throughout the subsoil
Baxton (MT) - have a paralithic contact at depths of 50 to 102 cm; have a lithic contact at depths of 102 to 152 cm
Belain (MT) - have a lithic contact at depths of 50 to 102 cm
Bitterroot (MT) - have a calcic horizon; have a paralithic contact at depths of 50 to 102 cm
Burnt Fork (MT) - have a calcic horizon; do not have sandy-skeletal material in the lower part of the subsoil
Chincap (WY) - have a lithic contact at depths of 50 to 102 cm
Hopley (MT) - have a paralithic contact at depths of 102 to 152 cm
Mott (ND) - do not have a horizon of secondary calcium carbonate accumulation; do not have more than 10 percent rock fragments
Relan (MT) - have hue redder than 10YR
Tally (MT) - do not have more than 15 percent rock fragments in the particle-size control section; have hue redder than 10YR
Unaweep (CO) - do not have more than 10 percent rock fragments; have hue redder than 10YR
Vebar (ND) - have a paralithic contact at depths of 50 to 102 cm
Victor (MT) - do not have a horizon of secondary calcium carbonate accumulation; are slightly acid to strongly acid
Weedzunit (MT) - do not have a horizon of secondary calcium carbonate accumulation; have a lithic contact at depths of 50 to 102 cm
GEOGRAPHIC SETTING:
Landform - alluvial fans, fan remnants, and stream terraces
Elevation - 995 to 1,460 meters
Slope - 0 to 25 percent
Parent material - alluvium from mixed sources
Climate - Long, cold winters; moist springs; warm summers
Mean annual precipitation - 330 to 432 millimeters
Mean annual air temperature - 4 to 7 degrees C
Frost-free period - 90 to 120 days
GEOGRAPHICALLY ASSOCIATED SOILS: None listed.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; moderately rapid permeability to 79 cm and rapid to very rapid below.
USE AND VEGETATION: Losttrail soils are mainly used for irrigated pasture and hayland, or for dryland pasture.
DISTRIBUTION AND EXTENT: Losttrail soils are of small extent in the intermountain valleys of southwest Montana. MLRA 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 2013; proposed in Ravalli County, Montana, 2008.
REMARKS: Diagnostic features and horizons recognized in this pedon are:
Mollic epipedon - from the surface to 20 cm (A horizon)
Cambic horizon - from 20 to 51 cm (Bw horizon)
Horizon of secondary calcium carbonate accumulation - from 51 to 79 cm (Bk horizon)
Particle-size control section - from 25 to 100 cm (part of the Bw horizon, Bk, and part of the C1)
Losttrail soils have a frigid temperature regime and an ustic moisture regime.
National Cooperative Soil Survey
U.S.A.