LOCATION COOLBRITH CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Pachic Argixerolls
TYPICAL PEDON: Coolbrith loam - cultivated (Colors are for dry soil unless otherwise noted.)
Apl--0 to 4 inches; dark gray (10YR 4/1) loam, very dark grayish brown (lOYR 3/2) moist; moderate very thick platy structure; soft, friable, slightly sticky, slightly plastic; many very fine and fine roots; many very fine and fine vesicular pores; medium acid (pH 5.8); abrupt smooth boundary. (4 to 5 inches thick)
Ap2--4 to 10 inches; dark gray (lOYR 4/1) loam, very dark grayish brown (lOYR 3/2) moist; strong fine angular blocky structure; slightly hard, friable, sticky, slightly plastic; many very fine, fine and common medium roots; many very fine and fine tubular and interstitial pores; slightly acid (pH 6.2); clear wavy boundary. (6 to 8 inches thick)
B21t--10 to 17 inches; dark grayish brown (lOYR 4/2) clay loam, very dark grayish brown (lOYR 3/2) moist; strong fine and medium angular blocky structure; hard, friable, sticky, plastic; many very fine, fine and common medium roots; common very fine and fine tubular and interstitial pores; common thin clay films lining pores and bridging mineral grains; slightly acid (pH 6.3); clear wavy boundary. (7 to 8 inches thick)
B22t--17 to 26 inches; dark brown (lOYR 4/3) heavy sandy clay loam, dark brown (lOYR 3/3) moist; moderate medium prismatic parting to strong medium angular blocky structure; hard, firm, sticky, plastic; common very fine and medium roots; many very fine and fine tubular pores; many thin clay films lining pores and on faces of peds; slightly acid (pH 6.3); gradual wavy boundary. (8 to 9 inches thick)
B31--26 to 35 inches; dark grayish brown (lOYR 4/2) gravelly sandy clay loam, brown (lOYR 4/3) moist; few fine faint dark yellowish brown (lOYR 4/4) mottles moist; massive; very hard, very firm, sticky, slightly plastic; few fine and medium roots; many fine interstitial and common very fine tubular pores; many thin clay films lining pores and bridging mineral grains; slightly acid (pH 6.3); gradual wavy boundary. (8 to 10 inches thick)
B32--35 to 43 inches; dark grayish brown (lOYR 4/2) gravelly sandy clay loam, brown (lOYR 4/3) moist, few fine dark yellowish brown (lOYR 4/4) mottles moist; very hard, firm, slightly sticky, nonplastic; common fine and medium roots; many fine interstitial and common very fine tubular pores common thin clay films lining pores and bridging mineral grains; slightly acid (pH 6.4); clear smooth boundary. (8 to 12 inches thick)
IIC--43 to 68 inches; light olive brown (2.5Y 5/4) coarse gravelly sand, dark grayish brown (2.5Y 4/2) moist; common medium distinct light olive brown (2.5Y 5/6) mottles moist; massive, hard, firm, nonsticky, nonplastic; few fine roots; slightly acid (pH 6.4).
TYPE LOCATION: Sierra County, California; approximately 3 miles west of Loyalton; 1,320 feet east and 990 feet south of center of sec. 9, T.21N., R.15E.
RANGE IN CHARACTERISTICS: The soil is moist from about November 15 until June 15. It is dry in the moisture control section all the rest of the year. The soil is saturated to within 25 to 40 inches of the surface during the spring. The mean annual soil temperature is about 48 degrees to 50 degrees F, and usually the soil temperature is above 41 degrees F, from about March 15 and above 47 degrees F. from about April 1 to November 1. The soils are medium acid to neutral and become less acid with depth. The base saturation exceeds 75 percent in all parts to a depth of 30 inches or more.
The A horizon is gray, dark gray, grayish brown or dark grayish brown (lOYR) dry. Chroma is 1 or 2 moist and dry.
The B2t horizon is grayish brown, dark grayish brown, brown or dark brown in lOYR hue. It is clay loam, sandy clay loam or silty clay loam, and has 27 to 35 percent clay. Rock fragments mostly gravel make up 15 to 24 percent of the volume.
The C horizon may be similar in texture to the B2t horizon or it may be unrelated.
COMPETING SERIES: These are the Dotta, Gorman, Miramar, Supan, Van Dusen, and Waha series. Dotts soils lack mottles and have 18 to 27 percent clay in the argillic horizon. Gorman and Van Dusen soils lack mottles and are not saturated at any time. Miramar soils have a parslithic contact at a depth of less than 40 inches. Supan soils have a lithic contact and have 7.5YR or redder hue in the argillic horizon. Waha soils have a lithic contact at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: The Coolbrith soils are nearly level to gently sloping and are in margins of basins at elevations of 4,500 to 5,500 feet. They formed in alluvium from mixed sources. The climate is cool semiarid with moist cold winters and warm dry summers. Mean annual precipitation is 14 to 20 inches. Average January temperature is 28 degrees F., average July temperature is 69 degrees F., and mean annual temperature is 48 degrees to 50 degrees F. The freeze-free season is 80 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Beckwourth, Bidwell, Bieber, Correco, and Ramelli soils. Beckwourth soils have less than 18 percent clay in the argillic horizon. Bidwell soils have calcareous horizons at depths of less than 40 inches. Bieber soils have duripans at a depth of less than 20 inches. Correco and Ramelli soils have clay texture in the argillic horizon. Ramelli soils lack argillic horizons.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow or very slow runoff; moderately slow permeability.
USE AND VEGETATION: Coolbrith soils are used for growing hay, improved pasture, and alfalfa. The vegetation in uncultivated areas is silver sagebrush, perennial and annual grasses, and forbs.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are of small extent.
MLRA OFFICE RESPONSIBLE: Reno, Nevada
SERIES PROPOSED: Sierra County, California, 1973.
REMARKS: These soils were formerly classified as Prairie soils.
OSED scanned by SSQA. Last revised by state on 8/73.
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.