LOCATION DUDGEN CAEstablished Series
TAXONOMIC CLASS: Clayey, smectitic, mesic, shallow Typic Durixeralfs
TYPICAL PEDON: Dudgen loam--on a 1 percent slope under a cover of low sagebrush and perennial grasses at an elevation of 3320 feet. When described on 6/4/82, the soil was slightly moist throughout. (Colors are for dry soil unless otherwise stated).
A--0 to 4 inches, light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; strong medium platy structure parting to moderate medium angular blocky; hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; many fine tubular and few medium vesicular pores; neutral (7.0); abrupt smooth boundary. (2 to 4 inches thick)
Bt1--4 to 8 inches; light brownish gray (10YR 6/2) clay loam, dark grayish brown (10YR 4/2) moist; weak fine prismatic structure parting to moderate fine subangular blocky; very hard, firm, slightly sticky and slightly plastic; few very fine and common fine roots; many very fine tubular pores; few moderately thick clay films on peds, and common thin clay films in pores; neutral (7.0); abrupt smooth boundary.
Bt2--8 to 15 inches; brown (10YR 5/3) clay, dark brown (10YR 4/3) moist; strong medium prismatic structure; extremely hard, very firm, slightly sticky and plastic; few very fine roots; common very fine tubular pores; common moderately thick clay films in pores; neutral (7.0); abrupt smooth boundary. (Combined thickness of the Bt horizons is 8 to 16 inches)
2Bqm--15 to 19 inches; duripan, indurated with a continuous 1/8 to 1/4 inch thick silica cemented capping underlain by extremely hard coarse alluvial material; platy structure; very firm moist. (2 to 12 inches thick)
2Bq--19 to 27 inches; light gray (10YR 7/2) very fine sandy loam, dark brown (10YR 5/3) moist; massive; very hard, firm, nonsticky and nonplastic; few very fine tubular pores; moderately alkaline (8.0); clear smooth boundary. (8 to 24 inches thick)
2C1--27 to 37 inches; light gray (10YR 7/2) very fine sandy loam, brown (10YR 5/3) moist; massive; very hard, friable, nonsticky and nonplastic; few very fine tubular pores; moderately alkaline (8.0); clear smooth boundary.
2C2--37 to 54 inches; light gray (10YR 7/2) loamy sand, dark brown (10YR 4/3) moist; few fine distinct yellowish red (5YR 5/6) mottles, reddish brown (5YR 4/4) moist; massive; very hard, friable, nonsticky and nonplastic; few very fine tubular pores; mildly alkaline (8.0);clear smooth boundary.
2C3--54 to 120 inches; stratified sandy loam, loamy sand, very fine sandy loam and silt loam.
TYPE LOCATION: Modoc County, California; about 1.2 miles northwest of Fall River Mills; 50 feet west and 550 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 minute series).
RANGE IN CHARACTERISTICS: Depth to duripan ranges from 10 to 20 inches and depth to stratified alluvium ranges from 12 to 34 inches. The mean annual soil temperature is 47 to 54 degrees F. The soil temperature exceeds 41 degrees F.
f.om mid February to late December and exceeds 47 degrees F. from mid April to early December. The soil moisture control section is dry in all parts from early July to early October and is moist in all parts from early November to early June. The particle size control section averages 40 to 60 percent clay. Organic carbon ranges from 0.55 to 0.40 percent to a depth of 4 to 10 inches and decreases regularly with depth. Base saturation ranges from 90 to 100 percent throughout the profile.
The A horizon color is 10YR 6/2, 6/3, 7/1 or 7/3. Moist color is 10YR 4/2, 4/3; 7.5YR 4/2, or 4/4. The clay content is 20 to 27 percent.
The Bt horizon color is 10YR 5/3, 6/2, 6/3, 7/1; 7.5YR 5/4 or 6/6. Moist color is 10YR 4/2, 4/3, 4/4; 7.5YR 4/2 or 4/4. It is clay loam in the upper part with 27 to 35 percent clay and clay in the lower part with 40 to 60 percent clay. The Bt horizon averages greater than 40 percent clay. Reaction is neutral or mildly alkaline.
The 2Bqm horizon has 1/8 to 1/4 inch thick continuous silica capping underlain by 2 to 12 inches of extremely firm or very firm coarse alluvium that is slightly or moderately brittle with platy structure or is massive.
The 2Bq and 2C horizons are stratified loamy sand to silt loam. Reaction is neutral to moderately alkaline.
COMPETING SERIES: There are no other soils in this family.
GEOGRAPHIC SETTING: Dudgen soils are on terraces. Slopes are 0 to 5 percent. These soils formed in alluvium from extrusive igneous rock. Elevation is 3,300 to 3,500 feet. The climate is semiarid with warm dry summers and cold moist winters. Mean annual precipitation is 16 to 20 inches. Snowfall is 20 to 30 inches. The mean annual temperatures is 50 to 52 degrees F. The mean January temperature is about 37 degrees F. The mean July temperature is about 66 degrees F. Frost-free period is 120 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dotta, Graven, and Pit soils. Dotta soils are fine-loamy, greater than 60 inches deep and on terraces. Graven soils are 20 to 40 inches deep and on mounds on terraces. Pit soils are greater than 60 inches and in basins.
DRAINAGE AND PERMEABILITY: Moderately well drained; slow to ponded runoff; slow permeability. The soils are occasionally flooded for periods of 2 to 7 days in January to April. A perched water table occurs at depths of 12 to 30 inches from November through June and brief periods ponding, 6 inches above the surface from December to April.
USE AND VEGETATION: This soil is used for livestock grazing and crops. The vegetation is low sagebrush, Lemmon needlegrass, and Sandberg bluegrass. Soils are cropped to pasture and alfalfa.
DISTRIBUTION AND EXTENT: Northeastern California. The soils are not extensive. MLRA is 21.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Shasta County, Intermountain Soil Survey Area, California 1994. Source of name is from Dudgen Butte, Burney Quadrangle.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the soil surface to 4 inches (A).
Argillic horizon - the zone from 4 to 15 inches (Bt1, Bt2)
Duripan - the zone from 15 to 19 inches (2Bqm)
ADDITIONAL DATA: Grab samples were sent to Lincoln Lab in 1983. Sample number is 837096 to 837098 for organic carbon and clay mineralogy, unpublished.