LOCATION CHURN CATentative Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Ultic Haploxeralfs
TYPICAL PEDON: Churn gravelly loam - pasture. (Colors for dry conditions unless otherwise noted).
A1--0 to 9 inches; light yellowish brown (10YR 6/4) gravelly loam, dark brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; plentiful micro roots; common very fine and few fine tubular pores; strongly acid (pH 5.5); gradual smooth boundary.
B1--9 to 13 inches; light yellowish brown (10YR 6/4) gravelly loam, dark brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; few very fine roots; common very fine and few fine tubular pores; common moderately thick clay films in bridges and pores and on partial ped faces; moderately acid (pH 6.0); clear smooth boundary.
B21t--13 to 29 inches; light yellowish brown (10YR 6/4) gravelly heavy loam, dark brown (7.5YR 4/4) moist; massive; slightly hard, friable, slightly sticky, slightly plastic; few very fine, medium and coarse roots; common very fine and fine tubular pores; many moderately thick clay films as bridges and pores and on partial ped faces; moderately acid (pH 6.0); gradual smooth boundary.
B22t--29 to 40 inches; light yellowish brown (10YR 6/4) gravelly clay loam, reddish brown (5YR 4/4) moist; weak coarse angular blocky structure; hard, firm, slightly sticky, slightly plastic; few fine, medium and coarse roots; common very fine and fine tubular pores; many moderately thick clay films as bridges and on partial ped faces and many thin clay films in pores; moderately acid (pH 6.0); gradual smooth boundary.
B23t--40 to 60 inches; strong brown (7.5YR 5/6) gravelly light clay loam, reddish brown (5YR 4/4) moist; strong medium angular blocky structure; hard, firm, slightly sticky, plastic; few fine and medium roots; few very fine and fine tubular pores; many moderately thick clay films as bridges and many thin clay films in pores; ped faces are coated with bleached sand grains very pale brown (10YR 7/3); moderately acid (pH 6.0).
TYPE LOCATION: Shasta County, California. About 7 miles west of Cottonwood, 180 feet north and 1,220 feet east of SW corner, sec. 2, T. 29 N., R. 5 W.
RANGE IN CHARACTERISTICS: The soils have ochric epipedons, argillic horizons with base saturation of less than 75 percent, mean annual soil temperature greater than 59 degrees F, and mineralogy is mixed. The solum thickness is over 60 inches. The soils are dry for more than 60 consecutive days.
The Churn soils have light yellowish brown, strongly acid, gravelly loam A horizons and light yellowish brown grading to strong brown gravelly clay loam, moderately acid Bt horizons. The C horizons where present are stratified gravelly alluvium.
The A horizon colors range from brown and yellowish brown to pale brown and light yellowish brown (7.5YR, 10YR) dry and dark grayish brown to dark yellowish brown and dark brown moist; textures range from loam to gravelly loam, structure from massive to weak granular and reaction from moderately acid to strongly acid.
The Bt horizons range in color from brown and strong brown to pale brown and light yellowish brown (7.5YR, 10YR) dry, and dark brown to reddish brown (7.5YR, 5YR) moist; in texture from gravelly heavy loam to clay loam, and in reaction from strongly acid to moderately acid.
The C horizons, where present, usually are moderately acid, stratified and gravelly sandy loams and loams.
COMPETING SERIES: In the same family, the Auberry soils, developed on granite, have a paralithic contact. Similar soils are the Anderson, Arbuckle, Perkins, Pleasanton and Tehama. The Anderson soils lack Bt horizons. Arbuckle soils have brown, slightly acid A horizons and slightly acid Bt horizons with base saturation greater than 75 percent. The Perkins soils have yellowish red, slightly acid heavy clay loam or clay Bt horizons. The Pleasanton soils have grayish brown A horizons and brown neutral Bt horizons with more than 75 percent base saturation. The Tehama soils have pale brown A horizons low in organic matter and light yellowish brown, slightly acid to neutral Bt horizons with more than 75 percent base saturation.
GEOGRAPHIC SETTING: The Churn soils occur on nearly level or gently sloping low terraces under oaks, shrubs and grasses. Underlying material is gravelly alluvium from various rocks. Elevations range from 400 to 800 feet. The climate is subhumid mesothermal with mean annual rainfall of 30 to 45 inches, with hot dry summers and cool moist winters. Mean annual temperature is about 62 degrees F, average January temperature about 45 degrees F, and average July temperature about 80 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: Churn soils occur in the same general area as the Anderson, Honcut, Perkins, Red Bluff and Tehama soils. Honcut soils lack argillic horizons. Red Bluff soils have red Bt horizons and abrupt A/B boundaries.
DRAINAGE AND PERMEABILITY: Well drained or moderately well drained; runoff is slow or medium and permeability is moderate to moderately slow.
USE AND VEGETATION: Dry grain, irrigated pasture and smaller areas in alfalfa, orchard, berries and truck crops. Natural vegetation is valley oaks, blue oaks, interior live oak, manzanita, annual grasses and forbs.
DISTRIBUTION AND EXTENT: Northern Sacramento Valley, California where the soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Shasta soil survey area, 1960. Name from Churn Creek.
REMARKS: The Churn series was formerly classified in the Noncalcic Brown group.
The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET
Last revised by the state on 8/66.