LOCATION JACKSBACK CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aquultic Haploxerolls
TYPICAL PEDON: Jacksback loam on a northwest-facing 1 percent slope under a cover of lodgepole pine, grasses and forbs at an elevation of 4870 feet. (Colors are for dry soil unless otherwise stated. When described October 18, 1989, the soil was slightly moist to 42 inches and moist below.)
A1--0 to 5 inches; brown (10YR 5/3) loam, very dark grayish brown (10YR 3/2) moist; moderate medium platy structure parting to moderate very fine subangular blocky; soft, very friable, nonsticky and nonplastic; common very fine and few fine roots; many very fine interstitial pores; 10 percent gravel; slightly acid (pH 6.0) abrupt smooth boundary.
A2--5 to 12 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak very fine subangular blocky structure; soft, very friable, nonsticky and slightly plastic; common very fine, and few fine and medium roots; common very fine interstitial pores; 10 percent gravel; slightly acid (pH 6.1); clear smooth boundary. (Combined thickness of the Al and A2 horizon is 11 to 15 inches)
Bw1--12 to 21 inches; brown (10YR 5/3) loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine interstitial pores; 5 percent gravel; slightly acid (pH 6.1); abrupt smooth boundary. (6 to 9 inches thick)
Bw2--21 to 34 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 4/3) moist; moderate fine subangular blocky structure; slightly hard, firm, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; 10 percent gravel; few fine distinct black and strong brown (N2/0 and 7.5YR 4/6) moist redox concentrations; slightly acid (pH 6.5); clear smooth boundary.
Bw3--34 to 42 inches; yellowish brown and pale brown (10YR 5/4 and 6/3) sandy clay loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and plastic; few very fine roots; many very fine tubular pores; 10 percent fine and medium irregular durinodes; 5 percent gravel; few fine distinct black and strong brown (N2/0 and 7.5YR 4/6) moist redox concentrations; slightly acid (pH 6.5) abrupt smooth boundary. (Combined thickness of the Bw2 and Bw3 horizon is 15 to 25 inches)
Bq1--42 to 52 inches; light yellowish brown (10YR 6/4) sandy loam, yellowish brown (10YR 5/4) moist; moderate medium platy structure; very hard, very firm, slightly sticky and plastic; common very fine tubular pores; few thick clay films on ped faces; 60 percent irregular durinodes; 10 percent gravel; few fine distinct yellowish brown (10YR 5/8) moist redox concentrations; neutral (pH 7.0); abrupt smooth boundary. (5 to 12 inches thick)
Bq2--52 to 61 inches; very pale brown (10YR 7/3) very fine sandy loam, yellowish brown (10YR 5/4) moist; massive; hard, firm, nonsticky and nonplastic; common very fine tubular pores; 30 percent fine and medium irregular durinodes; many medium distinct dark brown (7.5YR 3/4) moist redox concentrations; neutral (pH 7.0); abrupt smooth boundary. (8 to 12 inches thick)
C1--61 to 72 inches; very pale brown (10YR 7/4) coarse sandy loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, firm, nonsticky and nonplastic; many very fine interstitial pores; many medium distinct dark yellowish brown (10YR 4/6) moist redox concentrations; neutral (pH 7.0); abrupt smooth boundary.
C2--72 to 75 inches; very pale brown (10YR 7/4) sandy loam, yellowish brown 10YR 5/4 moist; strong fine platy structure; very hard, very firm, nonsticky and nonplastic; few very fine tubular pores; common fine rounded iron-manganese concretions; many medium distinct strong brown (7.5YR 5/8) moist redox concentrations; neutral (pH 7.0); abrupt smooth boundary. (Combined thickness of the C1 and C2 horizon is 9 to 16 inches)
C3--75 to 80 inches; very pale brown (10YR 7/4) silt loam, brown or dark brown (10YR 4/3) moist; massive; hard, firm, nonsticky and plastic; common fine tubular pores; many medium distinct, strong brown (7.5YR 4/6) moist redox concentrations; neutral (pH 7.0).
TYPE LOCATION: Shasta County, California about 10 miles southwest of Burney; 1,450 feet west and 200 feet south of the northeast corner of sec. 12, T. 33 N., R. 2 E., Manzanita Lake NW (Jacks Backbone) quadrangle (7.5 minute series).
RANGE IN CHARACTERISTICS: Thickness of the solum is 40 to 60 inches. The mean annual soil temperature is 41 to 45 degrees F. The soil temperature exceeds 41 degrees F.
from mid May to mid November (170-190 days) and exceeds 47 degrees F. from early July to early October. The soil moisture control section (7 to 20 inches) is dry in all parts from early August to early October (50 to 70 days) and is moist in all parts from late October to mid June. The particle-size control section (10 to 40 inches)averages 18 to 27 percent clay and 5 to 10 percent rock fragments. Base saturation by ammonium acetate is assumed to range from 50 to 60 percent.
The A horizon color is 10YR 4/2, 5/2 or 5/3. Moist color is 10YR 2/2, 3/2, or 3/3. Organic matter is assumed to range from 1 to 2 percent. Clay content ranges from 20 to 25 percent. Rock fragments, mostly gravel range form 5 to 10 percent. NaF pH ranges from 9.5 to 9.8.
The Bw horizon color is 10YR 5/3, 6/3, or 5/4. Moist color is 10YR 4/3, or 4/4. Moist redoximorphic color is N 2/0 7.5YR 2/0, 4/4, 4/6, 5/6 or 5/8. Texture is loam and sandy clay loam. Clay content ranges from 25 to 30 percent. Rock fragments, mostly gravel range from 5 to 10 percent. NaF pH ranges from 9.0 to 9.5.
The Bq horizon color is 10YR 6/4, 7/3, 7/4 or 8/3. Moist color is 10YR 5/4 or 6/4. Moist redoximorphic color is 10YR 5/8; 7.5YR 4/6 or 5/8. Clay content ranges from 12 to 18 percent. Rock fragments, mostly gravel range from 5 to 10 percent.
The C horizon color is 10YR 7/3, 7/4, 8/1; or 7.5YR 5/4. Moist color is 10YR 4/3, 6/3, 5/4; or 7.5YR 5/4. Moist mottle color is 7.5YR 3/4, 4/6 5/8; 10YR 4/6; 2.5Y 4/2, 6/2 or 5/4. Texture is very fine sandy loam, coarse sandy loam, sandy loam or silt loam. Clay content ranges from 12 to 20 percent. Rock fragments, mostly gravel range from 5 to 10 percent.
COMPETING SERIES: There are no other series in this family.
GEOGRAPHIC SETTING: Jacksback soils are on terraces. Slopes are 0 to 9 percent. These soils formed in alluvium from Andesitic rock. Elevation is 4700 to 5000 feet. The climate is subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 35 to 50 inches. Snowfall is 72 to 96 inches. The mean annual temperature is 39 to 41 degrees F. The mean January temperature is about 25 degrees F. The mean July temperature is about 55 degrees F. Frost-free season is 50 to 80 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Carberry, Gardens, Goulder and Stacher soils. Carberry soils are on lava plateaus and hills, are deep and are medial over loamy-skeletal. Gardens soils are in basins and have aquic moisture regime. Goulder soils are on mountains and lava plateaus, and are medial over loamy-skeletal. Stacher soils are on mountains and are medial over loamy-skeletal.
DRAINAGE AND PERMEABILITY: Poorly drained; medium to ponded runoff; moderately slow permeability. A water table occurs at depths of 0 to 36 inches from March through May and is below 40 inches from June through November.
USE AND VEGETATION: This soil is used for timber production and livestock grazing. The natural vegetation is lodgepole pine, woods rose, Douglas Sprirea blueberry, lemonade sumac Western serviceberry and some quaking Aspen.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are not extensive. MLRA is 22.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Shasta County, Intermountain Soil Survey Area, California 1990. Source of name is short for Jacks Backbone Mountain.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Base saturation data is assumed to verify Aquultic.
Mollic epipedon - the zone from the soil surface to a depth of 12 inches (A1, A2).
Cambic horizon - the zone from 12 to 52 inches (Bw1, Bw2, Bw3, Bq).