LOCATION FOUR STAR               CA+NV

Established Series
Rev. LNL/LW/JEB/TM
01/2019

FOUR STAR SERIES

The Four Star series consists of very deep, poorly drained and very poorly drained soils on flood plains and narrow canyon bottoms in mountainous areas. Slopes are 0 to 5 percent. Four Star soils formed in somewhat stratified ashy alluvium derived from tuffs or ignimbrites with some admixture from rhyolite, basalt, and andesite. The mean annual temperature is about 7 degrees C. and the mean annual precipitation is about 360 mm.

TAXONOMIC CLASS: Ashy, glassy, frigid Aquandic Endoaquolls

TYPICAL PEDON: Four Star ashy loam - meadow pastureland. (Colors are for moist soil unless otherwise stated.)

Oi--0 to 6 cm; very dark brown (10YR 2/2) slightly decomposed plant material, dark grayish brown (10YR 4/2) dry; massive; soft, very friable; many very fine roots; many very fine interstitial pores; neutral (pH 6.8); clear smooth boundary. (0 to 8 cm thick)

A1--6 to 20 cm; very dark gray (10YR 3/1) ashy loam, gray (10YR 5/1) dry; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; many very fine and fine roots; many very fine interstitial pores; common fine distinct dark brown (7.5YR 3/2) iron concentrations; neutral (pH 6.6); clear wavy boundary. (13 to 46 cm thick)

A2--20 to 76 cm; very dark grayish brown (10YR 3/2) ashy sandy loam, grayish brown (10YR 5/2) dry; massive; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine and few fine tubular pores; many fine and medium faint dark brown (7.5YR 3/3) and distinct yellowish brown (10YR 5/6) iron concentrations, and few coarse prominent dark greenish gray (5BG 4/1) redox depletions in the lower part; neutral (pH 6.6); diffuse smooth boundary. (18 to 69 cm thick)

Cg--76 to 152 cm; dark greenish gray (5BG 4/1) ashy sandy loam, grayish brown (2.5Y 5/2) dry; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine and fine roots; common very fine tubular and many very fine interstitial pores; 5 percent 2 to 5 millimeter gravel; common fine prominent dark brown (7.5YR 3/2) and common coarse prominent very dark grayish brown (10YR 3/2) iron concentrations in the upper part; slightly acid (pH 6.5).

TYPE LOCATION: Modoc County, California; on the Four Star ranch approximately 1,300 feet east and 1,300 feet south of the NW corner of sec. 1, T. 40 N., R. 16 E., Mount Diablo base line and meridian; USGS Eagleville 7.5 minute topographic quadrangle; latitude 41 degrees 21 minutes 56.1 seconds N and longitude 120 degrees 06 minutes 48.4 seconds W; WGS84 Decimal Degrees 41.3655833 latitude, -120.1134444 longitude..

RANGE IN CHARACTERISTICS:

Soil moisture: Saturated for one month or more within 46 cm of the surface during most years, unless drained.
Mean annual soil temperature: 6.5 to 8.0 degrees C.
Mollic epipedon thickness: 61 to 122 cm.
Profile reaction: Slightly acid to neutral; surface layer may range to moderately alkaline where carbonates are present.
Carbonates: Usually noncalcareous throughout, but is weakly effervescent or strongly effervescent in the upper 15 to 25 cm in some pedons.
Organic matter: These soils have an irregular decrease in organic matter.

Particle-size control section - Clay content: Averages 7 to 18 percent.
Rock fragments: 0 to 15 percent gravel.

A horizons
Hue: Neutral, 10YR or 2.5Y.
Value: 4 or 5 dry and 2 or 3 moist.
Chroma: 0 through 2.
Structure: Weak or moderate, fine to coarse subangular blocky structure or is massive. It is never both massive and hard when dry.
Redoximorphic features: Prominent high-chroma iron concentrations may occur in any part of the mollic epipedon; faint to prominent low chroma or yellowish or bluish hued depletions are common in the lower part.

Cg horizon
Hue: neutral, 2.5Y or 5Y dry, and neutral of 2.5Y to 5BG moist.
Value: 5 or 6 dry and 3 through 5 moist.
Chroma: 0 through 2.
Redoximorphic features: Distinct or prominent iron or manganese concentrations are in most pedons.
Other features: Buried A horizons are common.

COMPETING SERIES: These are the Middleres and Paulina series.
The Middleres soils have mollic epipedons that are 18 to 50 cm thick and ashy sandy textures below a lithologic discontinuity within the particle-size control section. Paulina series have 25 to 50 cm mollic epipedons and have 18 to 30 percent clay in the particle-size control section.

GEOGRAPHIC SETTING: Four Star soils are on nearly level to gently sloping flood plains and narrow canyon bottoms in mountainous areas at elevations of 1,340 to 1,980 meters. Slopes are 0 to 5 percent. The soils formed in somewhat stratified ashy alluvium derived from tuffs or ignimbrites with some admixture from rhyolite, basalt, and andesite. The climate is cool continental. The mean annual temperature ranges from 5.5 to 7.0 degrees C., and mean summer temperature from 15 to 17 degrees C. The mean annual precipitation ranges from 250 to 400 mm with most of it coming as snow. The frost-free period is 60 to 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Buntingville, Bidwell, Holtle, Hovey, and Tica soils and the competing Hussa soils. Buntingville soils have clay loam argillic horizons. Bidwell soils are well drained and have clay loam argillic horizons. Holtle soils are well drained and contain durinodes in a friable matrix. Tica soils have stony and gravelly clay argillic horizons and are 28 to 50 cm deep to bedrock. Hovey soils have clay loam control sections and prominent Ck horizons.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Poorly drained and very poorly drained; surface runoff is very slow; permeability is moderately rapid; saturated hydraulic conductivity class is moderately high. The water table fluctuates at depths less than 46 cm and may be at or near the surface in the very poorly drained areas. Drained phases are recognized.

USE AND VEGETATION: Used for either the production of meadow hay or to provide livestock grazing. Some areas have been plowed and seeded to clover grass hay mixtures and oats. The meadow vegetation is mainly sedge, carex, clover, bentgrass, and redtop with bluegrasses in better drained areas. Coarse sedges and carex grow in the more poorly drained areas.

DISTRIBUTION AND EXTENT: Northeastern California and northern Nevada. These soils are not extensive. MLRA 21, 23 and 25. (Areas of this soil mapped in MLRA 28A and MLRA 29 in southern Nevada are considered outside the concept and range of the Four Star series.)

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California

SERIES ESTABLISHED: Surprise Valley-Home Camp Area, California-Nevada; Modoc County, California, 1971.

REMARKS: Four Star soils were formerly classified as Humic Gley soils.
The 2006 reclassification is based on optical grain counts from the recovered type location and update to the current version of Soil Taxonomy.

Diagnostic horizons and features recognized in this pedon:
Mollic epipedon - The zone from the soil surface 6 to 76 cm (A1 and A2 horizons).
Aquandic feature - The mineral horizons in the upper 75 cm have 30 to 60 percent volcanic glass and ash in the coarse silt to sand fraction.
Particle-size control section - The zone from 25 to 100 cm (A2, Cg horizons).

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National Cooperative Soil Survey
U.S.A.