LOCATION VALCREEK CAEstablished Series
TAXONOMIC CLASS: Sandy-skeletal, mixed, mesic Typic Xerorthents
TYPICAL PEDON: Valcreek very gravelly loamy coarse sand--on a southeast facing convex slope of 65 percent under ponderosa pine, canyon live oak, greenleaf manzanita, and sugar pine at an elevation of 3,175 feet. (Colors are for dry soil unless otherwise stated. When described on July 7, 1981, soil was very slightly moist below 10 inches).
Oi--3 to 0 inches; needles, leaves, twigs and cones.
A1--0 to 3 inches; pale brown (10YR 6/3) very gravelly loamy coarse sand, dark grayish brown (10YR 4/2) moist; weak very fine subangular blocky structure; loose, nonsticky and nonplastic; many very fine roots; common very fine interstitial pores; 35 percent gravel; moderately acid (pH 6.0); clear wavy boundary. (2 to 4 inches thick).
A2--3 to 8 inches; pale brown (10YR 6/3) gravelly loamy coarse sand, dark grayish brown (10YR 4/2) moist; weak very fine granular structure; loose, nonsticky and nonplastic; common fine many very fine roots; common very fine interstitial pores; 25 percent fine gravel; moderately acid (pH 6.0); clear wavy boundary. (0 to 5 inches thick).
C1--8 to 16 inches; very pale brown (10YR 8/3) gravelly loamy coarse sand, yellowish brown (10YR 5/4) moist; single grained; loose, nonsticky and nonplastic; few fine and very fine roots; common very fine interstitial pores; 30 percent fine gravel; moderately acid (pH 6.0); gradual wavy boundary. (5 to 9 inches thick).
C2--16 to 31 inches; very pale brown (10YR 8/3) extremely gravelly loamy coarse sand, yellowish brown (10YR 5/4) moist; single grained; loose, nonsticky and nonplastic; few very fine roots; common very fine interstitial pores; 65 percent fine gravel; moderately acid (pH 6.0); clear irregular boundary. (5 to 22 inches thick).
Cr--31 inches; soft, weathered granitic rock; can be dug with a spade, with difficulty; material separates into individual coarse sand and fine gravel size particles when crushed; no roots.
TYPE LOCATION: Trinity County, California; about 1 mile south of Buckhorn Summit; 0.1 mile west of the entrance to Shingle Shanty, on Highway 299, turn south onto dirt road across Grass Valley Creek, take the left fork, go 1.2 miles south, and west off road 250 feet out spur ridge, and 50 feet downhill; 500 feet west and 1600 feet south of the northeast corner section 22, T.32N. R.8W. Shasta Valley Quadrangle. 40 degrees North latitude, 36 minutes, 14 seconds, 122 degrees West longitude, 44 minutes, 50 seconds.
RANGE IN CHARACTERISTICS: Depth to weathered granitic rock ranges from 20 to 40 inches. Some pedons have 10 to 30 percent of the surface covered with fine gravel. The soil moisture control section is dry in all parts from mid July to mid October (about 85 to 95 days). The soil temperature at 20 inches exceeds 41 degrees F from about mid April to late November (about 210 to 230 days), and exceeds 47 degrees F from early June to late October. The mean annual soil temperature is 47 to 52 degrees F. Rock fragments average 35 to 65 percent in the particle-size control section. Base saturation (ammonium acetate) ranges from 55 to 100 percent, with each pedon dominantly above 75 percent in the zone from 10 to 30 inches depth.
The A horizon is 10YR 6/3, 4/2, 5/3, 3/2, 4/1, 6/2, 5/1, 6/1 or 7/3. Moist color is 10YR 4/2, 2/1, or 3/1. It is moderately or strongly acid. The A horizon has 3 to 8 percent clay and 20 to 50 percent fine gravel. It is less than 7 inches thick in pedons where colors meet Mollic epipedon requirements.
The C horizon is a mixture of the following colors; 10YR 8/3, 6/4, 6/3, 6/2, 7/2, 8/2, 7/3, 5/2, 5/1, 8/1 or 5/3. Moist color is 10YR 5/4, 5/3, 2/2, 4/2, 3/2, 5/2, 6/4, 3/1, 4/1, 4/4, 6/3, 6/2, 8/1 or 7/3. It is gravelly loamy coarse sand, very gravelly loamy coarse sand, extremely gravelly loamy coarse sand, or extremely gravelly coarse sand. The C horizon has 25 to 65 percent fine gravel, and 2 to 6 percent clay. It is moderately to very strongly acid.
COMPETING SERIES: These are the Atter, Carlsborg, Cowlitz, Hoypus, and Spens series. These soils are greater than 60 inches deep to bedrock.
GEOGRAPHIC SETTING: The Valcreek soils are on mountains. Slopes are 30 to 75 percent. Elevation is 2,500 to 5,000 feet. These soils formed in residuum from weathered granitic rocks of the Shasta Bally Batholith. The climate is characterized by warm, dry summers and cool, moist winters. Mean annual precipitation is 55 to 65 inches. Snowfall ranges from 10 to 36 inches. Mean January temperature is 34 degrees F. Mean July temperature is about 68 degrees F. Mean annual temperature is about 45 to 50 degrees F. The frost-free season is 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Tallowbox, Minersville, and Choop soils. Minersville soils are greater than 40 inches deep over bedrock. Tallowbox soils have cambic horizons, and are coarse-loamy. Choop soils have weathered granitic rock at 10 to 20 inches.
DRAINAGE AND PERMEABILITY: Excessively drained; rapid to very rapid runoff; rapid permeability.
USE AND VEGETATION: The Valcreek soils are used mainly for timber production, water supply, and wildlife habitat. The vegetation is ponderosa pine, canyon live oak, tanoak, squawcarpet, greenleaf manzanita, and some sugar pine.
DISTRIBUTION AND EXTENT: The Valcreek soils are not extensive, and are in the Klamath Mountains of northern California. MLRA 5.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Trinity County, California, Weaverville Area, 1990. Soil name is coined from Grass Valley Creek.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon--the zone from the surface to a depth of 8 inches (A1, A2 horizons).
Particle-size control section--the zone from 10 inches to 31 inches (C1, C2 horizons).
Paralithic contact - the boundary at 31 inches (Cr).
ADDITIONAL DATA: NSSL pedon S83CA-105-009 (type location).
Field estimate by sieving for percent rock fragments, during NSSL characterization sampling was 65 percent in the C2 horizon. Fine pebbles were crushed during preparation and measured rock fragment content was lower.