LOCATION BECKWOURTH CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Oxyaquic Argixerolls
TYPICAL PEDON: Beckwourth loamy coarse sand--on a nearly level flood plain under silver sagebrush and perennial grasses at an elevation of 4,880 feet--rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 2.5 inches; very dark gray (10YR 3/1) loamy coarse sand, black (10YR 2/1) moist; moderate very thin platy structure; soft, very friable, nonsticky and nonplastic; many very fine, few fine and medium roots; many very fine tubular and interstitial pores; moderately acid (pH 5.7); clear wavy boundary.
A2--2.5 to 15 inches; dark grayish brown (10YR 4/2) loamy coarse sand, very dark brown (10YR 2/2) moist; weak thick platy structure; soft, very friable, nonsticky and nonplastic; few fine, medium and coarse roots; many very fine interstitial and common very fine and fine tubular pores; slightly acid (pH 6.5); clear wavy boundary. (Combined thickness of the A horizons is 9 to 18 inches.)
BA--15 to 23 inches; brown (10YR 5/3) loamy coarse sand, brown (10YR 4/3) moist; massive; slightly hard, friable, nonsticky and nonplastic; few fine, medium and coarse roots; many very fine interstitial and common very fine and fine tubular pores; few faint clay films lining pores; neutral (pH 7.0); clear smooth boundary. (4 to 6 inches thick)
Btk--23 to 34 inches; pale brown (10YR 6/3) coarse sandy loam, brown (10YR 5/3) moist; massive; hard, firm, slightly sticky and slightly plastic; few fine, medium and coarse roots; common very fine interstitial and common very fine and fine tubular pores; common faint clay films lining pores and bridging sand grains; strongly effervescent; secondary carbonates segregated in common medium distinct very pale brown (10YR 8/2) masses; very strongly alkaline (pH 9.1); clear smooth boundary. (6 to 12 inches thick.)
Bk1--34 to 48 inches; light yellowish brown (10YR 6/4) loamy coarse sand, brown (10YR 4/3) moist; massive; soft, friable, nonsticky and nonplastic; few fine roots; common fine interstitial pores; common fine faint very dark grayish brown (10YR 3/2) moist zones of iron depletion; slightly effervescent; secondary carbonates segregated in masses; strongly alkaline (pH 8.7); gradual smooth boundary. (8 to 16 inches thick)
Bk2--48 to 60 inches; pale brown (10YR 6/3) coarse sand, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; many very fine interstitial pores; very slightly effervescent; secondary carbonates segregated in masses; moderately alkaline (pH 8.2).
TYPE LOCATION: Plumas County, California; about 5.5 miles northwest of Loyalton and 530 feet north of a secondary road; approximately 3,120 feet north and 990 feet west of the southeast corner of section 21, T. 22 N., R. 15 E.; USGS Antelope Valley 7.5 minute topographic quadrangle; 39 degrees 44 minutes 46 seconds north latitude and 120 degrees 17 minutes 56 seconds, west longitude, NAD27.
RANGE IN CHARACTERISTICS:
Soil moisture - The soil moisture control section (12 to 32 inches) is dry in all parts from July 15 through November 15 (123 days). It is moist throughout from December 1 through April 15. The soil temperature exceeds 41 degrees F from March 15 through November 30 (260 days) and exceeds 47 degrees F. from April 1 through October 30; Aridic moisture regime that borders on xeric.
Mean annual soil temperature - 48 to 52 degrees F.
Mollic epipedon thickness - 10 to 15 inches; does not include the BA horizon.
Depth to base of argillic horizon - 30 to 40 inches.
Depth to redoximorphic features - 28 to 36 inches.
Particle-size control section - Clay content: 10 to 18 percent.
A horizons - Dry color: 10YR 3/1, 3/2, 3/3, 4/1, 4/2, 4/3, or 5/3.
Moist color: 10YR 2/1, 2/2, 3/1, 3/2, or 3/3.
Texture: Loamy coarse sand, loamy sand, or coarse sandy loam.
Reaction: Moderately acid through neutral.
Organic matter content: 1 or 2 percent.
Btk horizon - Dry color: 10YR 5/3, 5/4, 6/3, or 7/2.
Moist color: 10YR 3/3, 3/4, 4/3, or 5/3.
Texture: Coarse sandy loam or sandy loam.
Clay content: 10 to 18 percent.
Reaction: Slightly alkaline to very strongly alkaline (up to pH 9.6).
Effervescence: Very slightly effervescent or slightly effervescent.
Calcium carbonate equivalent: 1 to 5 percent.
Bk horizons - Dry color: 10YR 6/3, 6/4; 2.5Y 6/3 or 6/4.
Moist color: 10YR 4/3, 4/4; 2.5Y 4/3 or 4/4.
Texture: Loamy sand, loamy coarse sand, coarse sand, or sand.
Clay content: 0 to 10 percent.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Very slightly effervescent or slightly effervescent.
Redoximorphic features: Faint to distinct zones of iron depletion with chroma of 2 moist.
Calcium carbonate equivalent: 0 to 1 percent.
COMPETING SERIES: There are currently no other series in this family.
GEOGRAPHIC SETTING: Beckwourth soils are on flood plains and low stream terraces. These formed in alluvium derived from mixed rock sources. Slopes are 0 to 2 percent. Elevations range from 4,000 to 5,350 feet. The climate is semiarid with cool, moist winters and warm, dry summers. The mean annual precipitation is 12 to 18 inches much of which falls as snow. The mean annual temperature is 44 to 49 degrees F., the mean January temperature is about 30 degrees F., and the mean July temperature is about 69 degrees F. The frost-free period is 60 to 90 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Calpine, Ormsby, Loyalton, and Ramelli soils. Calpine, Ormsby, and Ramelli soils lack argillic horizons. Loyalton soils have a natric horizon.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; very low or low surface runoff; moderate permeability. Endosaturation is present with an apparent seasonal high water table within 3 feet of the soil surface (moderately deep free water occurrence class) between March and May. Cumulative annual duration class is Transitory. These soils are susceptible to rare flooding for very brief periods year-round or occasional flooding for brief periods between January and May.
USE AND VEGETATION: Beckwourth soils are used rangeland and irrigated hay crops. The natural vegetation is mainly silver sagebrush, dryland sedge, shoestring, and grasses.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are moderately extensive. The series concept and main acreage is in MLRA 21, while other acreage occurs in MLRA 26.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California.
SERIES ESTABLISHED: Plumas County (Sierra Valley Area), California, 1954.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - The zone from the soil surface to 15 inches (A1 and A2 horizons).
Argillic horizon - The zone from 23 to 34 inches (Btk horizon).
Identifiable secondary carbonates - The zone from 23 to 60 inches (Btk, Bk1, and Bk2 horizons).
Endosaturation feature - The condition of ground water with an upper boundary between 36 and 40 inches from March through May during normal years (parts of the Bk1 and Bk2 horizons).
Particle-size control section - The zone from 23 to 34 inches (Btk horizon).
ADDITIONAL DATA: The typical pedon at the series type location has full characterization by the Soil Survey Laboratory (SSL), as soil survey sample number S61CA-063-015 (pedon # 40A3022). Laboratory data shows the organic matter content to be marginal in the A2 horizon for a mollic epipedon. Data from other pedons in the same vicinity indicate organic matter is more than 1 percent.