LOCATION SOFGRAN CAEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed Typic Cryorthents
TYPICAL PEDON: Sofgran gravelly loamy coarse sand--forest land. (Colors are for dry soil unless otherwise noted.) The soil surface is covered with one inch of forest duff that is undecomposed pine needles. It also is partially covered with 20 percent gravel, 5 percent cobbles, 1 percent stones, and 3 percent boulders.
A1--0 to 3 inches; brown (10YR 5/3) gravelly loamy coarse sand, dark brown (10YR 3/3) moist; weak fine subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and common fine roots; common very fine interstitial pores; 25 percent gravel and 5 percent boulders; very strongly acid; clear wavy boundary. (2 to 4 inches thick)
A2--3 to 6 inches; brown (10YR 5/3) gravelly loamy coarse sand, dark brown (10YR 3/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and common fine roots; common very fine interstitial and tubular pores; 25 percent gravel; strongly acid; clear wavy boundary. (3 to 5 inches thick)
Bw1--6 to 9 inches; pale brown (10YR 6/3) very gravelly loamy coarse sand, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine to coarse roots; common very fine interstitial and tubular pores; 35 percent gravel; strongly acid; clear wavy boundary. (3 to 8 inches thick)
Bw2--9 to 19 inches; pale brown (10YR 6/3) very gravelly loamy coarse sand, brown (10YR 4/3) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, many fine, many medium, and many coarse roots; common very fine interstitial and tubular pores; 25 percent gravel and 10 percent cobbles; strongly acid; clear irregular boundary. (5 to 15 inches thick)
Bw3--19 to 27 inches; light yellowish brown (10YR 6/4) very gravelly coarse sand, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine to coarse roots; common very fine interstitial pores; 30 percent gravel and 5 percent cobbles; strongly acid; clear irregular boundary. (7 to 15 inches thick)
Bw4--27 to 45 inches; light yellowish brown (10YR 6/4) extremely gravelly loamy coarse sand, dark yellowish brown (10YR 4/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine and common fine roots; common very fine and common fine interstitial pores; 55 percent gravel and 20 percent cobbles; strongly acid; clear wavy boundary. (10 to 20 inches thick)
Bw5--45 to 60 inches; light yellowish brown (10YR 6/4) very gravelly loamy coarse sand, yellowish brown (10YR 5/4) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, few fine, and few medium roots; common very fine interstitial pores; 40 percent gravel and 15 percent cobbles; strongly acid.
TYPE LOCATION: Alpine County, California; on the Toiyabe National Forest about 0.3 mile southeast of Horse Meadow; approximately 1,500 feet south and 2,550 feet west of the northeast corner of section 7, T. 11 N., R. 19 E.; USGS Freel Peak 7.5 minute topographic quadrangle; 38 degrees 50 minutes 2.9 seconds north latitude and 119 degrees 53 minutes 24.1 seconds west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually moist in the moisture control section; moist fall, winter, and spring; usually dry July through early October; Xeric moisture regime.
Mean annual soil temperature - 40 to 44 degrees F.
Mean summer soil temperature - 44 to 47 degrees F.
Ochric epipedon thickness - 6 to 9 inches.
Depth to bedrock - 60 to 80 inches to a paralithic contact. The paralithic materials below the contact are weathered granitic rock such as granodiorite.
Particle-size control section - Clay content: Averages less than 10 percent; Rock fragments: Averages 35 to 60 percent, mainly gravel. The upper part typically ranges from 35 to 50 percent, and the lower part ranges from 60 to 80 percent. Lithology of fragments are granitic rocks such as granodiorite.
A horizons - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3, dry or moist.
Organic matter content: 2 to 4 percent.
Reaction: Very strongly acid or strongly acid.
Bw1, Bw2, and Bw3 horizons - Value: 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Texture: Gravelly loamy coarse sand, very gravelly loamy coarse sand, or very gravelly coarse sand.
Clay content: 3 to 10 percent.
Rock fragments: 25 to 40 percent, mainly gravel.
Reaction: Very strongly acid or strongly acid.
Bw4, Bw5, or C horizons (when present) - Value: 4 or 5 moist.
Chroma: 1 or 2, dry or moist.
Texture: Very gravelly loamy coarse sand or extremely gravelly loamy coarse sand.
Clay content: 3 to 10 percent.
Rock fragments: 50 to 80 percent, mainly gravel.
COMPETING SERIES: These are the Alflack, Canlodore, Castlepeak, Chena, Cryomont, Dagget, Eklutna, Graylock, Nataga, Nizina, Obscurity, Perfecto, Ragamuffin, Stecum, Studebaker, and Whittell series.
Alflack soils are moderately deep to lithic contacts. Canlodore soils have albic E horizons and an ustic moisture regime. Castlepeak soils have mean annual soil temperature of 34 to 39 degrees F. and average 60 to 90 percent rock fragments in the particle-size control section. Chena soils have mean annual soil temperature of 25 to 37 degrees F. Cryomont soils have more than 60 percent volcanic glass in the upper 4 to 6 inches. Dagget soils are deep to paralithic contacts. Eklutna and Nataga soils have a udic moisture regime. Graylock soils are deep to lithic contacts. Nizina soils have mean annual soil temperature of 32 to 35 degrees F. Obscurity and Studebaker soils have a udic moisture regime, do not have ochric epipedons, and have 15 to 50 percent volcanic glass in the particle-size control section. Perfecto soils have albic horizons and an ustic moisture regime. Ragamuffin, Stecum, and Whittell soils are moderately deep to paralithic contacts.
GEOGRAPHIC SETTING: Sofgran soils are on mountains. They typically occur on footslope and backslope positions. They formed in colluvium and residuum derived from granitic rocks. Slopes are 8 to 50 percent. Elevations range from 8,000 to 10,000 feet. The climate is subhumid-continental with cold, moist winters and cool, dry summers. The mean annual precipitation is 30 to 55 inches, 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 Klauspeak and Temo soils. Klauspeak soils have umbric epipedons. Temo soils are sandy and shallow to paralithic contacts.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; low or medium surface runoff; rapid permeability (high or very high saturated hydraulic conductivity).
USE AND VEGETATION: Sofgran soils are used for forest land, recreation, watershed, and wildlife habitat. The native vegetation is mainly a forest canopy of lodgepole pine, California red fir, and western white pine with an understory of pinemat manzanita, snowbrush ceanothus, snowberry, currant, bluegrass, and sedge.
DISTRIBUTION AND EXTENT: Eastern California, on the east side of the Sierra Nevada Range. These soils are moderately extensive. 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:
Ochric epipedon - The zone from the soil surface to 6 inches (A1 and A2 horizons).
Particle-size control section - The zone from 10 to 40 inches (Bw3 horizon and parts of the Bw2 and Bw4 horizons).