LOCATION CHINABUTTE IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Lithic Argixerolls
TYPICAL PEDON: Chinabutte very stony loam--on a slightly concave northeast facing slope of 22 percent at 4,500 feet elevation--native rangeland. (Colors are for dry soil unless otherwise noted. When described on October 16, 1985, the soil was dry throughout.) The soil surface has about 10 percent stone cover.
A--0 to 5 inches; brown (10YR 5/3) very stony loam; dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; many very fine and fine interstitial pores; 35 percent pebbles, 10 percent cobbles, and 15 percent stones; neutral (pH 6.7); clear smooth boundary. (4 to 8 inches thick)
Bt1--5 to 8 inches; brown (10YR 4/3) very gravelly clay loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine, few medium roots; common very fine tubular pores; few distinct clay films on faces of peds; 40 percent pebbles and 15 percent cobbles; slightly acid (pH 6.3); clear smooth boundary. (3 to 7 inches thick)
Bt2--8 to 15 inches; brown (10YR 5/3) extremely cobbly clay loam, brown (10YR 4/3) moist; weak very fine and fine subangular block structure; hard, friable, moderately sticky and moderately plastic; few very fine and fine roots; few very fine tubular pores; many distinct clay films on faces of peds; 30 percent pebbles and 50 percent cobbles; slightly acid (pH 6.3); abrupt wavy boundary. (3 to 9 inches thick)
R--15 inches; slightly fractured rhyolite.
TYPE LOCATION: Owyhee County, Idaho; about 18 miles south of Murphy; 2,376 feet north and 790 feet west of the southeast corner of section 26, T.5S., R.2W.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section is dry 75 to 90 consecutive days following the summer solstice; xeric moisture regime bordering on aridic.
Soil temperature - 47 to 52 degrees F.
Mollic epipedon thickness - 7 to 11 inches
Solum thickness and depth to bedrock - 14 to 20 inches
Particle-size control section (averages) - 27 to 34 percent clay; 35 to 75 percent rock fragments
Reaction - slightly acid or neutral
A horizon
Value: 4 or 5 dry
Chroma: 2 or 3, dry or moist
Rock fragments: 20 to 60 percent
Bt horizons
Hue: 7.5YR or 10YR
Value: 4 or 5 dry, 3 or 4 moist
Chroma: 3 or 4, dry or moist
Texture: GRV-CL, CBV-CL, CBX-CL, or GRX-CL
Clay content: 27 to 38 percent
Rock fragments: 35 to 80 percent (averaging more than 10 percent cobbles)
COMPETING SERIES: These are the Argabak, Bellehelen, Brier, Clovercreek, Duco, Gwin, Horseflat, Orhood, Reywat, Upatad, and Windry series. Argabak soils are less than 10 inches to bedrock. Bellehelen and Brier soils are moist for 10 to 20 days between July and October due to convection storms. In addition Bellehelen soils have bedrock within 14 inches. Clovercreek soils have less than 10 percent cobbles in the argillic horizon. Duco, Orhood, Reywat, and Upatad soils have an aridic moisture regime. Gwin soils have a component of loess and are dry only 60 to 75 consecutive days. Horseflat soils are dry for more than half the time when the soil temperature at the lithic contact is above 40 degrees F. and they also have silica coatings over 30 percent of the surface area of the bedrock. Windry soils have mollic epipedons more than 12 inches thick. Reywat soils have a weak accumulation of lime above the bedrock. Upatad soils have Bk horizons.
GEOGRAPHIC SETTING: Chinabutte soils are on side slopes and shoulders of foothills. They formed in residuum and colluvium derived from andesite or rhyolite. Elevations range from 3,700 to 5,350 feet. Slopes are 3 to 45 percent. The climate is cool and moist in the winter and hot and dry in the summer. Mean annual precipitation is 13 to 15 inches, mean annual temperature is 45 to 50 degrees F., and the frost-free period is 90 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Alibi, Dougal, and Reywat soils. Alibi soils are greater than 20 inches deep on lower sideslopes and footslopes. Dougal and Reywat soils are usually dry on summits and exposed aspects.
DRAINAGE AND PERMEABILITY: Well drained; medium to very high surface runoff; slow permeability.
USE AND VEGETATION: Chinabutte soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is low sagebrush, bluebunch wheatgrass, Idaho fescue, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Southwestern Idaho. This series is not extensive.
MLRA OFFICE RESPONSIBLE: Reno, Nevada.
SERIES ESTABLISHED: Owyhee County Area, Idaho, 1992.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 8 inches (A and Bt1 horizons).
Argillic horizon - The zone from 5 to 15 inches (Bt1 and Bt2 horizons).
Lithic contact - The boundary at 15 inches to underlying hard bedrock (R layer).
Particle-size control section - The zone from 5 to 15 inches (Bt1 and Bt2 horizons)