LOCATION GRAVEN CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Typic Durixerolls
TYPICAL PEDON: Graven silt loam--on a convex slope of 1 percent under a cover of softchess, medusahead, sandberg bluegrass and cheatgrass at an elevation of 3,320 feet. (Colors are for dry soil unless otherwise stated. When described on 6/4/82, the soil was slightly moist throughout.)
A1--0 to 3 inches; grayish brown (10YR 5/2) silt loam, dark brown (7.5YR 3/2) moist; strong medium platy structure parting to weak fine subangular blocky; very hard, friable, nonsticky and slightly plastic; common very fine roots; common very fine tubular and few vesicular pores; neutral (pH 6.6); abrupt smooth boundary. (2 to 5 inches thick)
A2--3 to 9 inches; grayish brown (10YR 5/2) silt loam, dark brown (7.5YR 3/2) moist; weak fine subangular blocky structure; very hard, firm, nonsticky and slightly plastic; common very fine, fine and few medium roots; many very fine tubular pores; neutral (pH 6.7); clear smooth boundary. (5 to 9 inches thick)
Bt1--9 to 14 inches; grayish brown (10YR 5/2) silt loam, very dark grayish brown (10YR 3/2) moist; weak fine prismatic structure parting to weak fine angular blocky; very hard, firm, slightly sticky and plastic; common very fine and few fine roots; many very fine tubular pores; common thin clay films in pores; neutral (pH 6.9); abrupt smooth boundary. (4 to 6 inches thick)
Bt2--14 to 20 inches; grayish brown (10YR 5/2) clay loam, dark brown (10YR 3/3) moist; strong medium prismatic structure parting to strong medium angular blocky structure; extremely hard, very firm, sticky and plastic; few very fine roots; many very fine tubular pores; common moderately thick clay films on peds; neutral (pH 7.0); clear smooth boundary.
Bt3--20 to 23 inches; brown (10YR 5/3) clay, dark grayish brown (10YR 4/2) moist; strong fine prismatic structure parting to strong fine angular blocky structure; extremely hard, very firm, sticky and plastic; few very fine roots; many very fine tubular pores; common moderately thick clay films on peds; slightly alkaline (pH 7.5); abrupt smooth boundary. (Combined thickness of the Bt horizon is 13 to 27 inches)
2Bqm--23 to 29 inches; Duripan, indurated, with a continuous 1/8 to 1/4 inch thick silica cemented capping, platy structure, brittle, common manganese stains. (4 to 12 inches thick)
2Bqk--29 to 35 inches; light brownish gray (10YR 6/2) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; moderate coarse subangular blocky structure, very hard, firm, nonsticky and nonplastic; few very fine roots; common very fine tubular pores; common fine irregular soft masses of lime; weakly cemented with silica; moderately alkaline (pH 8.4); clear smooth boundary. (5 to 12 inches thick)
2Bk--35 to 43 inches; light gray (10YR 7/2) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; massive, very hard, friable, nonsticky and nonplastic; few very fine roots; common very fine tubular pores; common fine irregular soft masses of lime; moderately alkaline (pH 8.5); clear smooth boundary. (4 to 12 inches thick)
3C1--43 to 54 inches; light gray (10YR 7/2) loam, dark yellowish brown (10YR 4/4) moist; massive; hard, friable, nonsticky and nonplastic; few very fine roots; common very fine tubular pores; strongly alkaline (pH 8.5); clear smooth boundary. (10 to 25 inches thick)
3C2--54 to 64 inches; light gray (10YR 7/2) very fine sandy loam, dark yellowish brown (10YR 4/4) moist; massive; hard, very friable, nonsticky and nonplastic; many very fine tubular pores; moderately alkaline. (pH 8.2)
TYPE LOCATION: Shasta County, California; about 1.2 mile northwest of Fall River Mills; 50 feet west and 530 feet south of the northeast corner of sec. 25, T. 37 N., R. 4 E., Fall River Mills SW (Fall River Mills) quadrangle (7.5 minutes series).
RANGE IN CHARACTERISTICS: Depth to duripan ranges from 20 to 40 inches and depth to unconformable stratified alluvium ranges from 25 to 52 inches. The mean annual soil temperature is 52 to 54 degrees F. The soil temperature exceeds 47 degrees F. from mid February to late December and exceeds 47 degrees F. from mid April to mid December. The soil moisture control section is dry in all parts from early July to early October (90 to 110 days) and is moist in all parts from early November to early June. Base saturation ranges from 75 to 100 percent throughout the profile.
The A1 horizon color is 10YR 5/2, 5/3, and 5/4. Moist color is 10YR 3/2, 3/3 and 7.5YR 3/2. Organic matter ranges from 1 to 2 percent. Clay content is 15 to 25 percent.
The A2 horizon color is 10YR 5/2 and 5/3. Moist color is 10YR 3/2, 3/3 and 7.5YR 3/2. Organic matter ranges from 1 to 2 percent. Clay content is 18 to 25 percent.
The Bt horizon color is 10YR 4/3, 5/2, 5/3 and 7.5YR 4/4. Moist color is 10YR 3/2, 3/3, 4/2, 4/3; 7.5YR 3/2, 4/4; and 5YR 3/4, 4/4. Organic matter in upper part ranges from 0.5 to 1.0 percent decreasing regularly with depth. The upper part of the Bt horizon is silt loam, loam, or clay loam and the clay content is 25 to 30 percent. The lower part is clay loam or clay and the clay content is 35 to 50 percent.
The 2Bqkm horizon has a 1/8 to 1/4 inch thick continuous silica capping underlain by 4 to 12 inches of firm or very firm; slightly or moderately brittle platy structure or massive. Reaction is slightly to strongly alkaline.
The 2Bqk and the 2Bk horizon is stratified loamy sand to silt loam. Reaction is slightly alkaline to strongly alkaline.
COMPETING SERIES: These are the Appledellia (ID), Oxbow (OR) series. Hibbard soils have a calcareous C horizon underlain by a calcareous duripan and a mean annual soil temperature of 47 to 51 degrees F. Oxbow soils have a calcareous duripan and greater than 50 percent clay in the textural control section. Salisbury soils have a duripan 4 to 5 feet thick and a mean annual soil temperature of 47 to 51 degrees F. Appledellia soils are ...
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dotta, Dudgen (T) and Pit soils. Dotta soils are greater than 60 inches deep and fine-loamy, Dudgen soils are 10 to 20 inches deep to duripan with an ochric epipedon, and Pit soils are greater than 60 inches deep.
GEOGRAPHIC SETTING: Graven soils are on terraces. Slopes are 2 to 5 percent. The soils formed in alluvium from extrusive igneous rocks, mainly basalt, with some influence of ash and diatamaceous earth. Elevations are 3,300 to 3,500 feet. The climate is subhumid with warm dry summers and cold moist winters. The average annual precipitation is 16 to 20 inches. Snowfall is 20 to 30 inches. Mean January temperature is 37 degrees F.; mean July temperature is 66 degrees F.; mean annual temperature is 50 to 52 degrees F. Frost-free period is 120 to 130 days.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow permeability. The soil may be occasionally flooded for periods of 2 to 7 days in January, February, March and April. A water table occurs at depths of 24 to greater than 60 inches from December through April. Water is perched above the duripan from November through March.
USE AND VEGETATION: This soil is mainly used for rangeland and cropland. Vegetation is low sagebrush, sandberg bluegrass, needlegrass, squirreltail, and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: Northeastern California. The series is not extensive. MLRA is 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Shasta County, Intermountain Soil Survey Area, California, 1983. Source of name is from Graven Ridge, Alturas Quadrange.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from the soil surface to 14 inches (A1, A2, Bt1).
Argillic horizon - the zone from about 9 to 23 inches (Bt1, Bt2, Bt3).
Duripan - the zone from 23 to 29 inches (Bqm).
ADDITIONAL DATA: This pedon was characterized by Lincoln Lab in 1984. Pedon Number is S 84CA-089-001, unpublished.