LOCATION CORRALVAL CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive Aquic Haplocryolls
TYPICAL PEDON: Corralval very gravelly coarse sandy loam--rangeland. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with 25 percent gravel.
A1--0 to 3 inches; dark grayish brown (10YR 4/2) very gravelly coarse sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; common very fine roots; common very fine tubular and interstitial pores; 45 percent gravel; moderately acid; clear wavy boundary. (1 to 5 inches thick)
A2--3 to 13 inches; dark grayish brown (10YR 4/2) very gravelly coarse sandy loam, very dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine and fine roots; common very fine tubular and interstitial pores; 45 percent gravel; slightly acid; clear wavy boundary. (8 to 15 inches thick)
A3--13 to 20 inches; dark grayish brown (10YR 4/2) very gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; many very fine through medium roots; common very fine tubular and interstitial pores; 40 percent gravel; slightly acid; clear wavy boundary. (5 to 10 inches thick)
A4--20 to 26 inches; grayish brown (10YR 5/2) gravelly coarse sandy loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and nonplastic; common very fine through medium roots; common very fine tubular and interstitial pores; common fine and medium distinct dark yellowish brown (10YR 3/4) moist irregular masses of iron accumulation in the matrix; 25 percent gravel; slightly acid; clear wavy boundary. (0 to 8 inches thick)
C1--26 to 45 inches; pinkish gray (7.5YR 6/2) very cobbly coarse sandy loam, brown (7.5YR 4/2) moist; massive; soft, very friable, slightly sticky and nonplastic; few very fine and common fine and medium roots; few very fine tubular and many very fine interstitial pores; many medium and coarse distinct reddish brown (5YR 4/4) moist irregular masses of iron accumulation in the matrix; 30 percent gravel and 25 percent cobbles; slightly acid; clear wavy boundary. (10 to 25 inches thick)
C2--45 to 60 inches; 60 percent pinkish gray (7.5YR 6/2) with 40 percent yellowish red (5YR 5/6) very cobbly loamy coarse sand, 60 percent brown (7.5YR 4/3) with 40 percent yellowish red (5YR 4/6) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine interstitial pores; areas with yellowish red color are very coarse irregular masses of iron accumulation in the matrix; 25 percent gravel and 25 percent cobbles; slightly acid.
TYPE LOCATION: Alpine County, California; on the Toiyabe National Forest in Corral Valley about 2 miles south of Rodriguez Flat; approximately 350 feet north and 1,800 feet east of the southwest corner of section 33, T. 8 N., R. 22 E.; USGS Lost Cannon Peak 7.5 minute topographic quadrangle; 38 degrees 29 minutes 18.5 seconds north latitude and 119 degrees 34 minutes 02.7 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section during late fall, winter, and spring; usually dry from July through early October; Xeric moisture regime.
Mean annual soil temperature - 44 to 47 degrees F.
Mean summer soil temperature - 47 to 54 degrees F.
Mollic epipedon thickness - 16 to 30 inches.
Depth to seasonal aquic conditions - 20 to 40 inches.
Depth to sandy-skeletal material - 30 to 40 inches.
Particle-size control section - Clay content: Averages 12 to 18 percent; Rock fragments: Averages 35 to 60 percent. Lithology of fragments are granitic rocks such or granodiorite, volcanic rocks such as tuff or andesite, and minor metamorphic rocks such as quartzite.
A1 horizon - Value: 4 or 5 dry, 2 or 3 moist.
Organic matter content: 3 to 5 percent.
Reaction: Moderately acid or slightly acid.
A2, A3, and A4 horizons (when present) - Value: 4 or 5 dry, 2 or 3 moist.
Texture: Very gravelly coarse sandy loam, gravelly coarse sandy loam, or very gravelly sandy loam.
Rock fragments: 25 to 60 percent.
Organic matter content: 2 to 4 percent.
Reaction: Moderately acid or slightly acid.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation, commonly in the A3 or A4 horizon.
C1 horizon - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 2 through 6, dry or moist.
Texture: Very cobbly coarse sandy loam or very gravelly coarse sandy loam.
Clay content: 12 to 18 percent.
Rock fragments: 35 to 60 percent.
Reaction: Moderately acid or slightly acid.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation.
C2 horizon - Hue: 10YR or 7.5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 2 through 6, dry or moist.
Texture: Very cobbly loamy coarse sand, very gravelly loamy coarse sand, or very gravelly coarse sand.
Clay content: 3 to 8 percent.
Rock fragments: 35 to 60 percent.
Reaction: Moderately acid or slightly acid.
Redoximorphic features: Redox concentrations occur as masses of iron accumulation.
COMPETING SERIES: These are the Becks, Slagamelt (T), and Wishard series.
Becks soils have an ustic moisture regime, have soil reaction that is slightly alkaline or moderately alkaline, and have mollic epipedons that are less than 16 inches thick. Slagamelt soils have an ustic moisture regime. Wishard soils have a udic moisture regime.
GEOGRAPHIC SETTING: Corralval soils are on alluvial fans and low stream terraces on mountain valleys. They formed in alluvium derived from mixed sources including granodiorite, tuff, andesite, and some quartzite. Slopes are 0 to 8 percent. Elevations range from 7,500 to 9,500 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 30 to 45 inches, the mean annual temperature is 36 to 39 degrees F., and the frost-free period is 30 to 60 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buggin, Hopeval, and Sofgran soils. Buggin soils are shallow to paralithic contacts. Hopeval soils are coarse-loamy and have an aquic moisture regime. Sofgran soils are sandy-skeletal and do not have aquic conditions within 40 inches of the soil surface.
DRAINAGE AND PERMEABILITY: Moderately well drained; very low surface runoff; moderately rapid permeability (high saturated hydraulic conductivity). Endosaturation is present with an apparent seasonal high water table between 1.6 and 3.3 feet (moderately deep free water occurrence class) between January and June. Cumulative annual duration class is Common. These soils are susceptible to rare flooding for very brief periods year-round.
USE AND VEGETATION: Corralval soils are used for rangeland, recreation, watershed, and wildlife habitat. The native vegetation is mainly silver sagebrush, rushes, and sedges.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are not extensive with about 650 acres of the series mapped to date. MLRA 22A.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Alpine County (Toiyabe National Forest Area), California, 2006.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 26 inches (A1, A2, A3, and A4 horizons).
Aquic conditions - The conditions of endosaturation and reduction between 20 and 60 inches at certain times during normal years (A4, C1, and C2 horizons).
Particle-size control section - The zone from 10 to 40 inches (A3 and A4 horizons and parts of the A2 and C1 horizons).