LOCATION CUPPY CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Chromic Durixererts
TYPICAL PEDON: Cuppy cobbly clay on a south facing 8 percent slope under a cover of mountain big sagebrush and scattered western juniper at an elevation of 4380 feet. (Colors are for dry soil unless otherwise stated. When described August 31, 1979, the soil was dry throughout.)
A1--0 to 2 inches; dark brown (10YR 3/3) cobbly clay, very dark grayish brown (10YR 3/2) moist; weak very fine granular structure; slightly hard, very friable, sticky and plastic; common very fine roots; many very fine interstitial pores; 15 percent cobbles; mildly alkaline (pH 7.6); abrupt smooth boundary. (1 to 3 inches thick)
A2--2 to 6 inches; dark grayish brown (10YR 4/2) clay, dark brown (10YR 3/3) moist; moderate fine and medium prismatic structure parting to moderate fine subangular blocky; hard, friable, sticky and plastic; common very fine, fine and medium roots; common very fine tubular pores; thin continuous pressure faces; 10 percent cobbles; mildly alkaline (pH 7.6); clear smooth boundary. (3 to 6 inches thick)
Ass--6 to 18 inches; dark grayish brown (10YR 4/2) clay, dark brown (10YR 3/3) moist; moderate medium and coarse prismatic structure parting to moderate medium subangular blocky; hard, friable, sticky and plastic; common very fine, fine and few medium roots; common very fine and medium tubular pores; continuous pressure faces; few intersecting slickensides; 5 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.0); gradual wavy boundary. (9 to 15 inches thick)
Bss--18 to 27 inches; brown (7.5YR 4/4) clay, dark brown (7.5YR 3/4) moist; moderate and coarse prismatic structure parting to moderate medium subangular blocky; extremely hard, firm, sticky and plastic; common very fine, fine and medium roots; common very fine, fine and medium tubular pores; continuous pressure faces; common intersecting slickensides; 5 percent gravel and 5 percent cobbles; moderately alkaline (pH 8.0); clear wavy boundary. (5 to 9 inches thick)
Bw--27 to 29 inches; strong brown (7.5YR 5/6) clay loam, brown (7.5YR 4/4) moist; massive; slightly hard, friable, sticky and slightly plastic; common medium very fine and medium roots; few very fine tubular pores; moderately alkaline (pH 8.0); abrupt wavy boundary. (2 to 5 inches thick)
2Bqm--29 to 31 inches; 1 cm indurated silica capping over cemented fine textured ash and few fine manganese concretions with platy structure. (1 to 2 inches thick)
3R--31 inches; hard basalt.
TYPE LOCATION: Lassen County, California; about 4 miles east of Dixie Valley Ranch headquarters on Dixie Ranch Rd.; 700 feet north and 700 feet west of the southeast corner of sec. 14, T. 35 N., R. 8 E., Little Valley NE (Dixie Peak) quadrangle (7.5 minute series)
RANGE IN CHARACTERISTICS: Depth to duripan is 20 to 38 inches and depth to bedrock is 21 to 40 inches. The mean annual soil temperature is 47 to 52 degrees F. The soil temperature exceeds 41 degrees F. from mid March to late November (260 days) and exceeds 47 degrees F. from mid May to early November. The soil moisture control section (7 to 20 inches) is dry in all parts from early July to early November (125 to 130 days) and is moist in all parts from mid November to early May. The particle size control section (10 inches to duripan) averages 35 to 60 percent clay and 0 to 25 percent rock fragments, mostly gravel and cobbles. Rock fragments, mostly cobbles on the soil surface, range from 15 to 25 percent. Base saturation by Hach Kit ranges from 95 to 100 percent. Vertical cracks 1/2 to 4 inches wide extend from the surface to a depth of 23 to 29 inches when the soil is dry from early July to early November (125 days). Few to common intersecting slickensides are in the lower part of the A horizon and upper part of the Bss horizon.
The A horizon color is 10YR 3/3, 4/2, 4/3, 5/2, 5/3; 7.5YR 3/2, or 4/2. Moist color is 10YR 2/2, 3/2, 3/3; 7.5YR 2/2, or 3/2. Rock fragments, mostly cobbles and gravel, range from 15 to 25 percent in the upper part and 0 to 15 percent in the lower part. Reaction is neutral or mildly alkaline.
The Bss horizon color is 7.5YR 4/4 or 5/4. Moist color is 7.5YR 3/4 or 4/4. Clay content ranges from 40 to 60 percent. Rock fragments, mostly cobbles or gravel, range from 0 to 10 percent. Reaction is mildly or moderately alkaline. Wedge shaped tilted aggregates occur in this horizon.
The Bw horizon color is 7.5YR 4/6 or 5/6. Moist color is 7.5YR 4/4 or 5/4. It is clay loam or clay with 35 to 60 percent clay and 0 to 10 percent rock fragments.
COMPETING SERIES: These are the Aikman (ID), Carney (OR), Cupvar (T CA), Gerlach (T CA), Getrail (T CA), Jenny (CA), Lassen (CA), Lecrag (CA), Montague (CA) and Peasley (ID) soils. Aikman, Carney, Gerlach, Getrail, Jenny and Lassen soils do not have a duripan. Gerlach, Jenny, and Lecrag are greater than 40 inches deep. Montague soils have a petrocalcic and gravelly loamy sand to gravelly loam textures below the duripan and have a lithic contact of basalt at 40 to 60 inches. Peasley soils have a duripan cemented with silica and calcium underlain with stratified alluvium. Cupvar soils are ...
GEOGRAPHIC SETTING: Cuppy soils are on lava plateaus. Slopes are 2 to 15 percent. These soils formed in alluvium from basalt and tuff. Elevation is 4400 to 5400 feet. The climate is semiarid with warm dry summers and cold moist winters. Mean annual precipitation is 14 to 16 inches. Snowfall is 12 to 36 inches. The mean annual temperature is 45 to 50 degrees F. The mean January temperature is about 27 degrees F. The mean July temperature is about 62 degrees F. Frost-free period is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Jellycamp (T), Longcreek, Ollierivas (T), and Vansickle (T) soils, and competing Lassen soils. Jellycamp soils are on intermounds on lava plateaus, are 10 to 20 inches deep with an abrupt textural change. Longcreek soils are on ridges of lava plateaus, 10 to 20 inches deep underlain by unweathered bedrock. Ollierivas soils are on mounds of lava plateaus, are not fine throughout. Vansickle soils are on intermounds, 10 to 20 inches deep and clayey skeletal.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; slow permeability.
USE AND VEGETATION: This soil is mainly used for livestock grazing. The vegetation is mountain big sagebrush, bottlebrush squirreltail, bluebunch wheatgrass, thurber needlegrass, and scattered western juniper.
DISTRIBUTION AND EXTENT: Northeastern Modoc Plateau, California. The soils are not extensive. MLRA is 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Lassen County, Intermountain Soil Survey rea, California 1994. Source of name is from a spring on the Little Valley Quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Duripan - the zone from 29 to 31 inches (2Bqm)
Lithic contact- the boundary at 31 inches (3R)
ADDITIONAL DATA: Reference samples were analyzed by BLM in 1979 for mineralogy.