LOCATION JORGE CA+NV

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

JORGE SERIES

The Jorge series consists of deep or very deep, well drained soils that formed in material weathered from basic volcanic rock. The Jorge soils are on hill slopes and mountain slopes. Slopes range from of 2 to 75 percent. The mean annual precipitation is 1015 milimetera and the mean annual temperature is 5 degrees C.

TAXONOMIC CLASS: Loamy-skeletal, isotic, frigid Andic Haploxeralfs

TYPICAL PEDON: Jorge series - on a northeast moderately steep slope of 20 percent under a cover of mixed conifers at 1951 meters elevation. (Colors are for dry soil unless otherwise noted.)

Oi--0 to 4 cm; litter and duff, mainly from manzanita.

A1--4 to 27 cm; brown (7.5YR 5/4) stony sandy loam, brown (7.5YR 4/4) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine, common medium and coarse roots; many very fine and fine interstitial pores; 10 percent pebbles, 5 percent stones, 1 percent cobbles; moderately acid (pH 5.6); clear smooth boundary.

A2--27 to 60 cm; brown (7.5YR 5/4) very gravelly sandy loam, brown (7.5YR 4/4) moist; weak very fine and fine subangular blocky structure; soft, friable, nonsticky and slightly plastic; many very fine and fine, common medium and coarse roots; many very fine and fine interstitial pores; 40 percent pebbles and 4 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (the combined thickness of the A horizons is 15 to 55 cm thick)

BA--60 to 85 cm; brown (7.5YR 5/4) very gravelly loam, brown (7.5YR 4/4) moist; weak fine subangular blocky structure; soft, friable, nonsticky and slightly plastic; common very fine, fine, medium and coarse roots; many very fine and fine interstitial and common very fine vesicular pores; 35 percent pebbles and 3 percent cobbles; moderately acid (pH 5.6); clear wavy boundary. (25 to 65 cm thick)

Bt--85 to 126 cm; brown (7.5YR 5/4) very gravelly loam, brown (7.5YR 4/4) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine, common medium and coarse roots; many very fine and fine interstitial and few very fine vesicular pores; few thin clay films as bridges; 40 percent pebbles, 2 percent cobbles; moderately acid (pH 5.8); gradual wavy boundary. (38 to 79 cm thick)

C--126 to 217 cm; dark yellowish brown (10YR 4/4) very gravelly sandy loam, dark yellowish brown (10YR 3/4) moist; massive; soft, very friable, nonsticky and nonplastic; few very fine roots; common very fine and fine interstitial pores; 45 percent pebbles and 2 percent cobbles; moderately acid (pH 5.8); gradual wavy boundary. (25 to 102 cm thick)

Cr--217 cm; weathered vesicular andesitic agglomerate.

TYPE LOCATION: Placer County, California (4 miles north of Tahoe City), 366 meters west of NE corner sec. 19, T.16N., R.17E. MDB&M.

RANGE IN CHARACTERISTICS:

The mean annual soil temperature varies from 4 to 8 degrees C. and the mean summer temperature varies from 10 to 12 degrees C. at 50 cm depth. The soils are moist between depths of 23 and 86 cm and are dry in all parts from late July until early October.

Thickness of the solum is 100 to 165 cm

Depth to weathered bedrock: 127 to 254 cm

Cobbles, stones and rock outcrops cover 5 to 15 percent of the surface area.

Mineralogy is influenced by vitric pyroclastic material.

0 horizons are 3 to 8 cm thick.

Base saturation: less than 50% and typically less than 30 due to the high amount of aluminum in the parent material.

A horizon:
Hue: 10YR, 7.5YR, 5YR
Value: 4, 5 or 6 dry, 2, 3 or 4 moist
Chroma: 2, 3 or 4 dry or moist
Texture of the fine earth fraction: coarse sandy loam, sandy loam or loam
Organic matter: 2 to 15 percent
Rock fragments: 15 to 45 percent consisting of gravel, cobbles and stones
Structure: single grained or has weak granular or weak subangular blocky
Reaction: neutral to moderately acid

Ba or Bw horizons:
Hue: 10YR or 7.5YR
Value: 5, 6 or 7 dry, 3 or 4 moist
Chroma: 3 or 4 dry or moist
Texture of the fine earth fraction: sandy loam, loam, sandy clay loam or clay loam
Rock fragments: 35 to 65
Clay content: 5 to 13 percent
Reaction: neutral to strongly acid

Bt horizon:
Hue: 10YR 7.5YR
Value: 5, 6 or 7 dry, 3 or 4 moist
Chroma: 3 or 4 dry or moist
Texture of the fine earth fraction: sandy loam, loam, sandy clay loam or clay loam
Rock fragments: 35 to 65
Clay content: 15 to 35 percent and averages 4 to 12 percent more than the A horizon
Reaction: slightly to very strongly acid

C horizon:
Hue: 10YR
Value: 5, 6 or 7 dry, 3 or 4 moist
Chroma: 3 through 6 dry or moist
Texture of the fine earth fraction: loamy sand, sandy loam
Rock fragments: 35 to 65
Clay content: 11 to 27 percent
Reaction: slightly to very strongly acid

COMPETING SERIES: There are no other series in this family at this time.

GEOGRAPHIC SETTING: Jorge soils are on gently sloping to strongly sloping plateaus and hills and moderately steep and steep mountains at elevations of 1830 to 2745 meters. They formed in colluvium over residuum from volcanic flow rock of andesite, basalt, and latite. The climate is cool continental with mean annual precipitation which varies from 580 to 1450 mm. The mean annual temperature is 5 degrees C., mean January temperature is -5 degrees C., and mean July temperature is 14 degrees C. The average frost-free season is less than 90 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Tahoma, and Waca soils. Tahoma soils have less than 35 percent rock fragments. Waca soils have volcanic bedrock at depths of 50 to 100 cm.

DRAINAGE AND PERMEABILITY: Well drained; low to high runoff; moderate permeability.

USE AND VEGETATION: Woodland; principal species are red fir, white fir, Jeffrey pine, western white pine, mountain whitethorn, greenleaf manzanita, prostrate manzanita, and squawcarpet.

DISTRIBUTION AND EXTENT: The higher elevations of the Sierra Nevada Mountains of California and Nevada. The soils of this series are of moderate extent. MLRA 22A

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

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

REMARKS: The Jorge soils were formerly classified as members of the loamy-skeletal, mixed family of Typic Cryoboralfs. The cryic soil temperature regime was based upon a thumb rule that 0 horizons are not considered unless the thickness is greater than 3 inches. This concept is not considered to be valid in California and conflicts with Soil Taxonomy. Some pedons are described as having Bw horizons in the upper colluvial part of the profile.

Classification was changed from Ultic Haploxeralfs after reviewing lab data, NSSL Pedon Number 00P0046

National Cooperative Soil Survey
U.S.A.