LOCATION MUG IDEstablished Series
TAXONOMIC CLASS: Clayey-skeletal, smectitic, frigid Ultic Palexerolls
TYPICAL PEDON: Mug very cobbly loam - on a slope of 4 percent under rangeland vegetation at 5,600 feet elevation. When described on November 11, 1981, the soil was dry throughout. (Colors are for dry soil unless otherwise noted.)
A--0 to 5 inches; grayish brown (10YR 5/2) very cobbly loam, very dark grayish brown (10YR 3/2) moist; weak medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; many roots; many very fine tubular pores; 20 percent cobbles, 20 percent gravel; slightly acid (pH 6.4); abrupt smooth boundary. (4 to 7 inches thick)
Bt1--5 to 14 inches; grayish brown (10YR 5/2) extremely gravelly clay loam, very dark grayish brown (10YR 3/2) moist; strong fine angular blocky structure; hard, firm, sticky and plastic; common very fine and fine roots; many very fine tubular pores; common distinct clay films on faces of peds and in pores; 30 percent cobbles, 40 percent gravel; slightly acid (pH 6.3); abrupt smooth boundary. (0 to 9 inches thick)
2Bt2--14 to 25 inches; brown (7.5YR 5/4) gravelly clay, dark brown (7.5YR 4/4) moist; strong coarse prismatic structure; extremely hard, very firm, very sticky and very plastic; few very fine or fine roots; few very fine tubular pores; many prominent clay films on faces of peds and in pores; 20 percent gravel, 5 percent cobbles; neutral (pH 6.7); abrupt smooth boundary. (9 to 20 inches thick)
2R--25 inches; gray (10YR 6/1) welded tuff, dark gray (10YR 4/1) moist; thin inconsistent calcium carbonate-silica coating on the rock surface.
TYPE LOCATION: Twin Falls County, Idaho about 21 miles southwest of Rogerson, Idaho; in the southwest 1/4, southwest 1/4, southwest 1/4, section 6, T. 15 S., R. 13 E.
RANGE IN CHARACTERISTICS:
Depth to the welded tuff - 20 to 40 inches
Mollic epipedon - 7 to 15 inches
Average clay percent in the control section - 35 to 60
Base saturation upper 20 inches of argillic horizon - 65 to 75 percent Rock fragments in the control section - 40 to 80 percent
Average annual soil temperature - 44 to 46 degrees F.
Moisture, soil - dry for more than 90 consecutive days during the summer
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 through 3 dry or moist
Bt1 horizon
Chroma - 2 or 3 dry or moist
Texture - GRV-C, GRX-CL
Gravel - 35 to 50 percent
Cobbles - 5 to 30 percent
2Bt2 or Btb horizons
Hue - 10YR or 7.5YR
Value - 4 to 6 dry
Chroma - 2 through 4 dry or moist
Texture - GR-C, CB-C, GBX-SICL, CBX-SIC, and CBV-SIC
Gravel - 5 to 25 percent
Cobbles - 5 to 60 percent
Stones - 0 to 20 percent
Reaction - moderately acid to neutral
COMPETING SERIES: This is the Boiler, Hudspeth, and the Player series. Boiler and Player soils are greater than 60 inches deep to bedrock. Hudspeth soils are usually moist and are dry between a depth of 4 and 12 inches for less than 90 consecutive days during the summer.
GEOGRAPHIC SETTING: Mug soils are on terraces basalt plains and foothills. The slope ranges from 1 to 12 percent. The soils formed in colluvium and residuum from welded tuff and loess over weathered loess and residuum from welded tuff or basalt. Elevations are 5,000 to 6,300 feet. The average annual precipitation ranges from 12 to 16 inches. The average annual temperature is 43 to 45 degrees F. The frost free season is 60 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Amboat, Arness, Brose, Eep, and Dehana soils. Amboat and Brose soils occur on summits. Amboat soils are deep. Brose soils are shallow, and are not skeletal. Arness soils occur on lower terraces, and have sandy clay loam or sandy clay argillic horizons. Dehana and Eep soils are deep, and occur on sideslopes or breaks.
DRAINAGE AND PERMEABILITY: Well drained, medium runoff; very slow permeability.
USE AND VEGETATION: Mug soils are used for rangeland. Native vegetation is bluebunch wheatgrass, Idaho fescue, and low sagebrush.
DISTRIBUTION AND EXTENT: Mug soils are of small extent in south central Idaho.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - 0 to 14 inches (A and Bt1 horizons)
Argillic horizon - 5 to 25 inches (Bt1 and 2Bt2 horizons)
Particle-size control section - 5 to 25 inches (Bt1 and 2Bt2 horizons)
Ultic feature - BS less than 75 percent in some part of upper 20 inches
Pale feature - abrupt boundary to a clayey Bt horizon
Lithic contact - at 25 inches
ADDITIONAL DATA: Clay percent by hydrometer: 0-5 inches-20 percent; 5-14 inches-36 percent; 14-25 inches-58 percent; base saturation: 0-5 inches-76 percent; 5-14 inches-67 percent; 14-25 inches-78 percent.