LOCATION PLUMAS CAEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, mesic Pachic Haploxerolls
TYPICAL PEDON: Plumas very gravelly sandy loam - on a 2 percent slope at about 3,500 feet elevation. (Colors are for dry soil unless otherwise stated. When decribed August 26, 1982 the soil was dry to 27 inchs and slightly moist below.)
A1--0 to 7 inches; grayish brown (10YR 5/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, friable, nonsticky and slightly plastic; many very fine roots; common very fine tubular pores; 20 percent 2 to 5 mm pebbles; 20 percent 5 to 75 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (4 to 16 inches thick)
A2--7 to 13 inches; dark grayish brown (10YR 4/2) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; common very vine roots; common very fine tubular pores; 20 percent 2 to 5 mm pebbles; 25 percent 5 to 75 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (6 to 18 inches thick)
A3--13 to 29 inches; brown (10YR 5/3) very gravelly sandy loam, very dark grayish brown (10YR 3/2) moist; massive; slightly hard, very friable, nonsticky and slightly plastic; common very fine roots; common very fine tubular pores; 20 percent 2 ot 5 mm pebbls; 20 percent 5 to 75 mm pebbles; slightly acid (pH 6.5); clear wavy boundary. (8 to 26 inches thick)
C--29 to 60 inches; brown (10YR 5/3) very gravelly sandy loam, dark brown (10YR 3/3) moist; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine roots; common very fine tubular pores; 20 percent 2 to 5 mm pebbles; 40 percent 5 to 75 mm pebbles; slightly acid (pH 6.5).
TYPE LOCATION: Plumas County, California; in the north arm of Indian Valley, 500 feet southwest of County Road 213 where it crosses Cooks Creek; about 400 feet east and 2,400 feet north of the southeast corner of section 2, T.26N., R.10E.
RANGE IN CHARATERISTICS: The mean annual soil temperature at a depth of 20 inches varies from 47 degrees to 50 degrees F. The mean summer soil temperature at 20 inches varies from 63 degrees to 65 degrees F and the mean winter soil temperature varies from 32 to 34 degrees F. The soil moisture control section is moist in all parts from December 1 to May 15. It is dry in all parts from about July 15 to September 15. The soil temperature at a depth of 20 inches exceeds 41 degrees F from about April 15 to November 15. Thickness of the mollic epipedon is 38 to 60 inches. The 10 to 40 inch control section has a weighted avrage content of 10 to 18 percent clay, 55 to 65 percent sand and 35 to 60 percent rock fragments, mostly gravel. Reaction is slightly acid or neutral. Base saturation is assumed to be greater than 75 percent throughout.
The A horizon is 10YR 4/2, 4/3, 5/2 or 5/3. Moist color is 10YR 2/1, 2/2, 3/2 or 3/3.
The C horizon is 10YR 5/3, 5/4, 6/4 or 2.5Y 6/4. Moist color is 10YR 3/3, 4/4 or 2.5Y 4/4. Texture is sandy loam, coarse sandy loam or stratified sandy loam and loamy sand and is modified by 40 to 70 percent rock fragments, mostly gravel.
COMPETING SERIES: These are the Dehlinger, Drit, Gamboa, Langrell, Packard (T) and Wrentham soils. The Dehlinger soils have a mollic epipedon that is 20 to 35 inches thick and have 18 to 30 percent clay in the control section. The Drit soils have a mollic epipedon that is 20 to 38 inches thick and the moisture control section is dry 90 consecutive days. The Gamboa soils are 40 to 60 inches deep to a lithic contact and havea mean annual soil temperature of 54 degrees to 58 degrees F. Langrell soils are only dry for 60 to 80 days following the summer solstice and are very cobbly or extremely cobbly. The Packard soils have a mean annual soil temperature of 52 degrees to 57 degrees F and have 25 to 35 percent clay in the control section. The Wrentham soils are 20 to 40 inches deep to hard bedrock.
GEOGRAPHIC SETTING: Plumas soils are on alluvial fans. Elevation is 3,400 to 3,550 feet. Slopes are 0 to 5 percent. These soils formed in mixed allvuium predominantly from metasedimentary rock. The climate is subhumid with warm dry summers and cool moist winters. Mean annual precipitation is about 35 inches. Mean January temperature is about 34 degrees F, mean July temperature is about 66 degrees F and the mean annual temperature is about 50 degrees F. Frost-free season is 80 to 100 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Forgay and Keddie soils. The Forgay soils have an ochric epipedon. Keddie soils are poorly drained and are fine-loamy.
DRAINAGE AND PERMEABILITY: Well drained; slow to medium runoff; moderately rapid permeability.
USE AND VEGETATION: Used mainly for dryland pasture with some area becoming urbanized. Vegetation is mostly grasses and forbs with the variety and composition determined by past and present use.
DISTRIBUTION AND EXTENT: Western Plumas County, California in American and Indian Valleys. These soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Plumas National Forest Area, California 1984.
REMARKS:
The superactive cation exchange activity class was added in 03/2003 to the taxonomic classification by the National Soil Survey Center on request of the Reno MLRA office, without review of the soil series property data. The remainder of this document has not been updated.