LOCATION DEMASTERS ID+OR WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Pachic Ultic Argixerolls
TYPICAL PEDON: Demasters loam--range. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 0.5 inches; relatively undecayed leaves and twigs. (0 to 1/2 inch thick)
Oe--0.5 to 2 inches; very dark grayish brown (10YR 3/2) partly decomposed leaves and twigs, black (10YR 2/1) moist; matted; neutral. (0 to 1/2 inch thick)
A1--2 to 16 inches; very dark brown (10YR 2/2) loam, slightly darker very dark brown (10YR 2/2) moist; moderate very fine granular structure; soft, very friable, slightly sticky, slightly plastic; many roots; many very fine and fine tubular pores; few very fine pebbles; few uncoated silt and very fine sand grains; neutral (pH 6.8); clear wavy boundary.
A2--16 to 23 inches; very dark grayish brown (10YR 3/2) loam, very dark brown (10YR 2/2) moist; moderate very fine granular structure; soft, very friable, slightly sticky, slightly plastic; many roots; many very fine and fine tubular pores; few fine pebbles; neutral (pH 6.7); gradual wavy boundary. (Combined thickness of the A horizon is 14 to 26 inches)
Bt1--23 to 30 inches; dark brown (10YR 3/3) loam, very dark brown (10YR 2/2) moist; weak coarse and medium subangular blocky structure; slightly hard, very friable, slightly sticky, slightly plastic; many roots; many very fine and fine tubular pores; common faint clay films on faces of peds; few angular fine pebbles; neutral (pH 6.6); gradual wavy boundary.
Bt2--30 to 37 inches; similar to Bt1 horizon except brown (10YR 4/3) dry, very gravelly loam, dark brown (10YR 3/3) moist; about 50 percent rock fragments, mostly fine gravel; clear wavy boundary. (Combined thickness of the Bt horizon is 11 to 24 inches)
C1--37 to 45 inches; brown (10YR 5/3) gravelly loam, dark brown (7.5YR 3/3) moist; massive; slightly hard, very friable, slightly sticky, slightly plastic; common roots; common very fine tubular pores; about 50 to 60 percent gravel and cobbles; neutral (pH 7.0); gradual wavy boundary. (0 to 8 inches thick)
C2--45 to 54 inches; mottled strong brown (7.5YR 5/6), brown (7.5YR 4/2), gray (N 5/0), and weak red (2.5YR 5/2) very gravelly loam; massive; slightly hard, very friable, slightly sticky, slightly plastic; common fine roots; common very fine tubular pores; common distinct clay films on some fragments; about 70 to 80 percent partially decomposed angular basalt gravel and cobbles; neutral (pH 7.0); gradual wavy boundary. (0 to 9 inches thick)
C3--54 to 63 inches; moderately weathered, disintegrated basalt; light gray (N 6/0 ) coarse sandy loam in the fractures that has light yellowish brown (10YR 6/4) and brown (7.5YR 5/4) staining; neutral (pH 6.9); gradual irregular boundary. (3 to 10 inches thick)
R--63 inches; slightly weathered basalt.
TYPE LOCATION: Gem County, Idaho; about 10 miles north of Ola; 20 feet east and 540 feet south of the center of sec. 34, T. 12 N., R. 1 E. (70 percent northerly slope at 4,000 feet elevation.)
RANGE IN CHARACTERISTICS:
Mollic epipedon - 30 to 55 inches thick
Depth to bedrock - 40 to 60 inches or more
Average annual soil temperature - 43 to 47 degrees F.
Average summer soil temperature - 59 to 65 degrees F.
Solum reaction - slightly acid to neutral
Base saturation above 30 inches - 50 to 75 percent
Rock fragments - 0 to 20 percent in the A and Bt1 horizons, 35 to 50 percent in the Bt2 horizons, average 20 to 35 percent in the Bt horizon, 50 to 80 percent in the lower part of the C horizon
A horizon:
Value - 2 through 4 dry, 1 or 2 moist
Chroma - 1 or 2, dry or moist
Organic matter - 4 to 8 percent to a depth of at least 10 inches
Bt horizon:
Hue - 10YR or 7.5YR
Value - 3 through 5 dry, 2 or 3 moist
Chroma - 2 or 3, dry or moist Textures - L, SIL, CL, SICL, GBV-L, GRV-L, CB-L, CBV-L, CBV-CL, or CB-SICL
Clay - has 3 to 6 percent more than the A horizon
COMPETING SERIES: These are the Bauscher, Brinegar, Bringmee, Oldbutte, Pinehurst, and Watchabob series.
Bauscher soils - have mollic surface less than 30 inches.
Brinegar soils - have redoximorphic features above 40 inches and are saturated with water in early spring.
Bringmee soils - have 15 to 30 percent fine sand and coarser in the upper argillic and significant amounts of volcanic ash.
Oldbutte soils - have less than 35 percent rock fragments in the lower part of the argillic horizon.
Pinehurst soils - have mollic epipedons that are 20 to 30 inches thick.
Watchabob soils - have bedrock above 40 inches.
GEOGRAPHIC SETTING: Demasters soils are usually on north exposures of undulating to very steep hills, canyons, and mountains. Slopes range from 3 to 90 percent. The soils formed in colluvium or residuum from basalt or other basic igneous rock at elevations of 3,000 to 6,000 feet. The climate is cool subhumid, with an average annual temperature of 41 to 45 degrees F, and with an average annual precipitation of 17 to 24 inches including 5 to 10 feet of snow. Summers are moderately dry. The average frost-free period is 80 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bluesprin, Boles, Gwin, Keuterville, Mehlhorn, Meland, Riggins, Suloaf, Uptmor, and Waha soils. All of these soils are mollic, but not pachic, except for the Waha series. The Waha series is pachic but not ultic. All of the above named soils, except for Suloaf, are on ridgetops, plateaus, or steep slopes with southerly aspects. Suloaf soils are on plateaus and steep northerly mountain slopes.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderate permeability.
USE AND VEGETATION: These soils are used primarily for livestock grazing. The potential natural vegetation is snowberry, mallow ninebark, Idaho fescue, prairie junegrass, bluegrass, chokecherry, serviceberry, pine reedgrass, elk sedge, lupine, and in places, scattered ponderosa pine and aspen.
DISTRIBUTION AND EXTENT: Southwestern and west-central Idaho, southeastern Washington, and northeastern Oregon; MLRA 10, 9. The series is moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gem County, Idaho, 1962.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the surface to 43 inches (A1, A2, Bt1, Bt2, and C1 horizons)
Argillic horizon - 3 to 6 percent more clay than A horizon (Bt1 and Bt2 horizons)
Base saturation - 50 to 75 percent above 30 inches
Rock fragments - average less 35 percent in control section
Moisture regime - xeric
Temperature regime - frigid