LOCATION KIYI IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Pachic Ultic Argixerolls
TYPICAL PEDON: Kiyi gravelly loam -- on a southeast facing slope of 8 percent, in native rangeland at 6,070 feet elevation. (When described on September 6, 1978, the soil was slightly moist below 17 inches. Colors are for air dry soils unless otherwise stated.)
A--0 to 2 inches; dark grayish brown (10YR 4/2) gravelly loam, very dark brown (10YR 2/2) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium roots; common very fine and fine tubular pores; 15 percent gravel; neutral (pH 6.7); clear smooth boundary. (2 to 5 inches thick)
AB--2 to 8 inches; grayish brown (10YR 5/2) gravelly loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; common very fine and fine tubular pores; 15 percent gravel; neutral (pH 6.6); gradual smooth boundary. (4 to 9 inches thick)
Bt1--8 to 16 inches; grayish brown (10YR 5/2) gravelly clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and plastic; common very fine and fine, few medium roots; common very fine and fine tubular pores; 20 percent gravel; common moderately thick clay films on faces of peds; slightly acid (pH 6.5); gradual wavy boundary. (6 to 12 inches thick)
Bt2--16 to 25 inches; brown (10YR 5/3) very gravelly clay loam, dark brown (10YR 3/3) moist; moderate medium and fine subangular blocky structure; very hard, firm, sticky and plastic; few very fine, fine and medium roots; few very fine and fine tubular pores; 30 percent gravel, 10 percent cobbles; common moderately thick clay films on faces of peds and in pores; slightly acid (pH 6.4); gradual smooth boundary. (0 to 12 inches)
Bt3--25 to 40 inches; pale brown (10YR 6/3) gravelly clay, brown (10YR 4/3) moist; strong fine and medium angular blocky structure; extremely hard, very firm, sticky and plastic; few fine roots; few very fine tubular pores; 20 percent gravel; continuous clay pressure faces on peds; slightly acid (pH 6.1); gradual wavy boundary. (10 to 15 inches thick)
C--40 to 60 inches; very pale brown (10YR 7/3) very cobbly clay, brown (10YR 5/3) moist; weak fine angular blocky structure; extremely hard, extremely firm, sticky and plastic; few very fine pores; 30 percent gravel, 30 percent cobbles; continuous clay pressure faces on peds; slightly acid (pH 6.1).
TYPE LOCATION: Owyhee County, Idaho; about 7 1/2 miles west and 3 miles north of Silver City; 1500 feet east and 1320 feet south of the northwest corner of sec. 24, T.4S., R.5W.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 47 degrees F.
Average summer soil temperature - 61 to 66 degrees F.
Thickness of mollic epipedon - 20 to 30 inches
Solum thickness - 40 or more inches
Particle-size control section - 35 to 50 percent clay; 20 to 35 percent rock fragments
A and AB horizons
Value - 3 through 5 dry, 2 or 3 moist
Chroma - 1 or 2 dry or moist
Rock fragments - 5 to 25 percent
Reaction (pH) - neutral or slightly acid
Bt horizon (upper part)
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry or moist
Texture - GR-CL or GRV-CL
Clay content - 28 to 38 percent clay
Rock fragments - 20 to 45 percent
Reaction (pH) - slightly or moderately acid
Bt horizon (lower part)
Value - 5 or 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - GR-C or CB-C
Clay content - 40 to 55 percent clay
Rock fragments - 20 to 35 percent
Structure - angular blocky or prismatic
Reaction (pH) - slightly or moderately acid
C horizon (when present)
Hue - 10YR or 2.5Y
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 3 or 4 dry or moist
Texture - CBV-C, CBV-SC, or STV-C
Clay content - 35 to 55 percent clay
Reaction (pH) - slightly or moderately acid
COMPETING SERIES: These are the Bertag, Sweiting, and Top series. Bertag soils have less than 20 percent rock fragments in the Bt horizons and have A horizons 12 to 26 inches thick. Sweiting soils are less than 40 inches to bedrock. Top soils have a solum thickness less than 40 inches thick.
GEOGRAPHIC SETTING: Kiyi soils occur on sideslopes and toeslopes of undulating to steep mountains and foothills at elevations of 5,100 to 6,600 feet. Slopes range from 3 to 40 percent. These soils formed in residuum and slope alluvium from rhyolite. The climate is cool and moist in the winter and hot and dry in the summer. Average annual precipitation ranges from 16 to 20 inches, and average annual temperature is 39 to 45 degrees F. Frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Hurryback (T), Sharesnout (T), and Snell soils. Hurryback soils have less than 35 percent clay in the texture control section. Sharesnout soils have mollic epipedons less than 20 inches thick. Snell and Sharesnout soils have greater than 35 percent rock fragments in the texture control section.
DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff; very slow permeability.
USE AND VEGETATION: Kiyi soils are used mainly for rangeland and wildlife habitat. The dominant natural vegetation is mountain big sagebrush, mountain snowberry, and Idaho fescue. mulesear wyethia commonly dominates this site.
DISTRIBUTION AND EXTENT: Southwestern Idaho. This series is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Owyhee County Area, Idaho, 1992.
REMARKS: Diagnostic horizons and other features recognized in this pedon:
Mollic epipedon - zone 0 to 25 inches (A, AB, Bt1, Bt2)
Argillic horizon - zone 8 to 40 inches (Bt1, Bt2, Bt3)
Particle-size control section - zone 8 to 28 inches (Bt1, Bt2, part of Bt3)
Base saturation (between 50 and 75 percent) - zone 8 to 30 inches (Bt1, Bt2, part of Bt3)