LOCATION DRYGULCH MT
Established Series
Rev. EMR/JMS/RJS
07/2013
DRYGULCH SERIES
The Drygulch series consists of very deep, somewhat excessively drained soils that formed in gravelly alluvium. These soils are on stream terraces and inset fans. Slopes are 0 to 8 percent. Mean annual precipitation is about 330 mm and mean annual air temperature is about 6 degrees C.
TAXONOMIC CLASS: Sandy-skeletal, mixed, frigid Aridic Haplustolls
TYPICAL PEDON: Drygulch coarse sandy loam, in rangeland on a 1 percent slope at 1,002 meters elevation (colors are for dry soil unless otherwise indicated.)
A--0 to 25 cm; grayish brown (10YR 5/2) coarse sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; very friable, soft, nonsticky and nonplastic; many fine roots, common medium roots; many fine irregular pores; 10 percent gravel; neutral (pH 7.0); abrupt smooth boundary. (18 to 28 cm thick)
BC--25 to 33 cm; pale brown (10YR 6/3) gravelly coarse sandy loam, brown (10YR 4/3) moist; weak fine subangular blocky structure; very friable, soft, nonsticky and nonplastic; common fine and medium roots; common fine irregular pores; 15 percent gravel; neutral (pH 7.0); gradual smooth boundary. (5 to 25 cm thick)
C1--33 to 46 cm; pale brown (10YR 6/3) very gravelly coarse sandy loam, brown (10YR 4/3) moist; massive; loose, nonsticky and nonplastic; few fine roots; common fine interstitial pores; 40 percent gravel; neutral (pH 6.8); gradual smooth boundary. (13 to 46 cm thick)
C2--46 to 152 cm; light yellowish brown (2.5Y 6/3) very gravelly loamy coarse sand, light olive brown (2.5Y 5/3) moist; single grain; loose, nonsticky and nonplastic; few fine roots; common fine interstitial pores; 40 percent gravel; neutral (pH 6.8).
TYPE LOCATION: Stevensville topographic quadrangle, Ravalli County, Montana; 660 meters north and 115 meters east of the SW corner of section 12, T. 9 N., R. 20 W. UTM Zone 11: 724962e, 5159409n, NAD 83.
RANGE IN CHARACTERISTICS:
Mean annual soil temperature - 5 to 8 degrees C
Mollic epipedon thickness - 18 to 28 cm
Gravel throughout the profile is dominantly 2 to 10 mm in size.
A horizon
Value: 4 or 5 dry; 2 or 3 moist
Chroma: 2 or 3 dry or moist
Texture: coarse sandy loam, sandy loam
Clay content: 5 to 20 percent
Rock fragments: 0 to 35 percent--0 to 35 percent gravel, 0 to 5 percent cobbles
Reaction: pH 6.6 to 7.4
BC horizon
Value: 3 or 4 moist
Chroma: 2 or 3 dry or moist
Texture: coarse sandy loam, sandy loam, loamy coarse sand
Clay content: 5 to 15 percent
Rock fragments: 15 to 35 percent--15 to 35 percent gravel, 0 to 10 percent cobbles
Reaction: pH 6.6 to 7.3
C1 horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4, dry or moist
Texture: coarse sandy loam, loamy sand, loamy coarse sand, coarse sand
Clay content: 0 to 15 percent
Rock fragments: 35 to 60 percent--25 to 60 percent gravel, 0 to 10 percent cobbles
Reaction: pH 6.6 to 7.3
C2 horizon
Hue: 10YR or 2.5Y
Value: 6 or 7 dry; 4, 5, or 6 moist
Chroma: 2, 3, or 4, dry or moist
Texture: loamy sand, loamy coarse sand, coarse sand
Clay content: 0 to 10 percent
Rock fragments: 35 to 60 percent--25 to 60 percent gravel, 0 to 10 percent cobbles
Reaction: pH 6.6 to 7.3
COMPETING SERIES:
Dominson (CO, UT) - have secondary calcium carbonate accumulation in the subsoil; are slightly alkaline to strongly alkaline
Millpoint (MT) - have a Bw horizon; have more than 10 percent rock fragments greater than 75 mm in the subsoil
Tiechute (MT) - have more than 10 percent rock fragments greater than 75 mm in the lower part of subsoil
Vendome (MT) - have a cambic horizon; have horizons of secondary calcium carbonate accumulation
GEOGRAPHIC SETTING:
Landform - stream terraces and inset fans
Elevation - 980 to 1,265 meters
Slope - 0 to 8 percent
Parent material - alluvium
Climate - long, cold winters; moist springs; warm summers
Mean annual precipitation - 305 to 380 mm, much of which falls as snow and as spring rain
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 a depth of 46 cm and rapid below.
USE AND VEGETATION: Drygulch soils are used mainly for irrigated pasture and hayland, or for dry-land pasture.
DISTRIBUTION AND EXTENT: Drygulch soils are of small extent in valleys of western Montana. MLRA 44A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana.
SERIES ESTABLISHED: Bitterroot Valley Area, Montana, 2013; proposed in Ravalli County, Montana, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from 0 to 25 cm (A horizon)
Particle-size control section - from 25 to 100 cm (BC, C1, and part of the C2 horizons)
Drygulch soils have a frigid temperature regime and an ustic moisture regime bordering on aridic.
National Cooperative Soil Survey
U.S.A.