LOCATION JABU CA+NV

Established Series
Rev. JHR/GMK/WRL/ET
01/2023

JABU SERIES

The Jabu series very deep, well drained soils that formed in outwash and alluvium from granitic sources. Jabu soils are on glacial outwash terraces and moraines and have slopes of 0 to 30 percent. The mean annual precipitation is about 760 mm and the mean annual temperature is about 5 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Ultic Haploxeralfs

TYPICAL PEDON: Jabu coarse sandy loam - forested. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 3 cm; Slightly decomposed plant material consisting of pine and fir needles.

A1--3 to 8 cm; brown (7.5YR 5/4) coarse sandy loam, dark brown (7.5YR 3/2) moist; weak thick platy structure; soft, very friable, nonsticky and nonplastic; many very fine, few fine roots; common very fine interstitial pores; 13 percent gravel; moderately acid (pH 5.6); clear smooth boundary. (5 to 15 cm thick)

A2--8 to 18 cm; brown (7.5YR 5/4) coarse sandy loam, reddish brown (5YR 4/4) moist; weak medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; many very fine, common fine, medium and coarse roots; common very fine interstitial, few fine tubular pores; 14 percent gravel; moderately acid (pH 6.0); clear smooth boundary. (10 to 30 cm thick)

Bt1--18 to 28 cm; brown (7.5YR 5/4) coarse sandy loam, reddish brown (5YR 4/4) moist; weak medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; common thin clay films in bridges and coatings sand grains; 14 percent gravel; moderately acid (pH 5.8); clear smooth boundary. (10 to 38 cm thick)

Bt2--28 to 53 cm; strong brown (7.5YR 5/6) coarse sandy loam, dark reddish brown (5YR 3/4) moist; massive; hard, friable, nonsticky and nonplastic; many very fine, fine, medium and coarse roots; common very fine tubular and interstitial pores; many thin clay films in bridges and coating sand grains; clay films moderately thick in places; 14 percent gravel; strongly acid (pH 5.5); abrupt wavy boundary. (20 to 30 cm thick)

Bt3--53 to 76 cm; strong brown (7.5YR 5/6) gravelly coarse sandy loam, yellowish red (5YR 4/6) moist; brown (7.5YR 5/4) coatings; massive; hard, firm, slightly sticky and slightly plastic; few very fine, fine, medium and coarse roots; common very fine tubular and interstitial, few fine tubular pores; many thin, few moderately thick clay films in bridges and coating sand grains; few cobbles on upper boundary of horizon; 27 percent gravel; strongly acid (pH 5.5); gradual boundary. (20 to 30 cm thick)

Bt4--76 to 97 cm; strong brown (7.5YR 5/6, 5/8) gravelly coarse sandy loam, yellowish red (5YR 5/6) moist; brown (7.5YR 5/4) coatings; massive; hard, firm, slightly sticky and slightly plastic; few fine, medium and coarse roots; common very fine interstitial and tubular, few fine tubular pores; continuous thin, few moderately thick clay films in bridges and coating sand grains; 26 percent gravel; strongly acid (pH 5.5); gradual wavy boundary. (18 to 30 cm thick)

Bt5--97 to 117 cm; strong brown (7.5YR 5/6, 5/8) gravelly coarse sandy loam, yellowish red (5YR 4/8) moist; massive; hard, firm, slightly sticky and slightly plastic; very few fine, medium and coarse roots; common very fine interstitial pores; continuous moderately thick yellowish red (5YR 4/6) clay films in bridges and coating sand grains; 44 percent gravel; strongly acid (pH 5.5); abrupt wavy boundary. (18 to 25 cm thick)

Bx1--117 to 135 cm; variegated reddish yellow and strong brown (7.5YR 6/6, 5/6) loamy coarse sand, strong brown (7.5YR 5/6, 5/8) moist; brownish yellow (10YR 6/6) moist; massive; hard, firm; common very fine interstitial pores; common thin clay films line pores; 7 percent gravel; strongly acid (pH 5.5); clear wavy boundary. (13 to 18 cm thick)

Bx2--135 to 170 cm; light gray (2.5Y 7/2) coarse sandy loam, olive gray (5Y 5/2) moist; dark grayish brown (2.5Y 4/2) bands; massive; extremely hard, extremely firm; few very fine interstitial pores; 10 percent gravel; strongly acid (pH 5.5); clear wavy boundary. (13 to 36 cm thick)

C--170 to 185 cm; white (N 8/) finely stratified fine sandy loam and silty clay, light gray (N 7/) moist; black coatings dry and moist; strong medium platy structure; slightly hard, firm, nonsticky and plastic; whole horizon has horizontal bands of clay and silt with black coatings between the plates; 6 percent gravel; strongly acid (pH5.5). (0 to 15 cm thick)

Cd--185 to 257 cm; light gray (2.5Y 7/2) compacted till, grayish brown (2.5Y 5/2) moist, coarse sandy loam; horizon was augered; 10 to 20 percent gravel.

TYPE LOCATION: El Dorado County, California; 4.5 meters north of Fountain Place Road, 5 1/2 miles south of Bijou, California; 0.2 mile east of SW corner sec. 23, T.12N., R.18E.

RANGE IN CHARACTERISTICS:

Soil moisture: The soils are usually moist in some part between depths of 20 and 61 cm inches most of the year, but are dry in all parts from early July until early in October.

Soil temperature: The mean annual soil temperature is 7 to 8 degrees C. at a depth of 50 cm and the mean summer soil temperature is 15.5 to 17.2 degrees C.

Depth to fragic soil properties: 100 to 200 cm.

Depth to compacted till: greater than 150 cm.

Rock fragments: 0 to 20 percent stones and cobbles.

Base saturation: argillic horizon is between 35 and 75 percent.

Reaction: slightly or moderately acid

The A horizon:

Hue: 10YR or 7.5YR dry, 10YR, 7.5YR, 5YR moist
Value: 4 or 5 dry
Chroma: 2 through 4 dry or moist
Structure: weak platy to strong granular structure

Bt horizons:
Hue: 10YR or 7.5YR dry, 10YR, 7.5YR, 5YR moist
Value: 4 through 8 dry or moist
Chroma: 3 or 6 dry or moist.
Texture of the fine earth: loamy coarse sand and coarse sandy loam
Rock fragments: 0 to 20 percent gravel
Clay content: 3 to 6 percent more clay than the A horizon.
Structure: weak blocky structure or is massive.
Reaction: moderately or strongly acid

Bx horizons:
massive, have bleached seams, and are hard to extremely hard dry and firm to extremely firm moist.

COMPETING SERIES: This is the Lasco series. Lasco soils have weathered bedrock between 40 and 60 inches deep.

GEOGRAPHIC SETTING: Jabu soils are on gently sloping to moderately steep glacial outwash, moraines, and terraces at elevations of 1890 to 2260 meters. They formed in coarse textured alluvium derived mainly from granitic sources. The climate is cool continental. Mean annual precipitation is about 580 to 1040 inches. The mean annual temperature is 5 degrees C., mean January temperature is -3 degrees C., and the mean July temperature is 16 degrees C. The frost-free season is less than 100 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Gefo and Christopher soils. Gefo and Christopher soils lack argillic horizons.

DRAINAGE AND PERMEABILITY: Well to moderately well drained; low to medium runoff; slow permeability.

USE AND VEGETATION: Used for home sites, range, and woodland. The principal native plants are Jeffrey pine, white fir, lodgepole pine, incense cedar, mountain whitehorn, mahala mat, greenleaf manzanita, and perennial grasses.

DISTRIBUTION AND EXTENT: The Lake Tahoe Basin, California and Nevada. The series is not extensive. MLRA 22A

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

SERIES ESTABLISHED: Tahoe Basin Area, California and Nevada, 1970.

REMARKS: Jabu soils would have been formerly classified as Alluvial soils.

National Cooperative Soil Survey
U.S.A.