LOCATION REDDING                 CA

Established Series
Rev. SBJ/DJL/DJE/MAV/AJT/SBS/AEC
03/2018

REDDING SERIES


The Redding series consists of moderately deep to duripan, well or moderately well drained soils that formed in alluvium derived from mixed sources. They are on nearly level or dissected fan remnants. Slopes are 0 to 30 percent. The average annual precipitation is about 24 inches (630 mm) and the average annual temperature is about 63 degrees F (17 degrees C).

TAXONOMIC CLASS: Fine, mixed, active, thermic Abruptic Durixeralfs

TYPICAL PEDON: Redding gravelly loam - on an east facing slope of 1 percent with mound and swale micro topography, about halfway between a mound and a swale, under annual grasses and forbs, at 315 feet elevation (96 m). (Colors are for dry soil unless otherwise noted. When described on April 2, 1945, the soil was moist throughout.)

A1--0 to 8 inches (0 to 20 cm); yellowish red (5YR 5/6) gravelly loam, dark reddish brown (2.5YR 3/4) moist; weak medium granular structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine roots, many very fine pores; 17 percent gravel; moderately acid (pH 5.7); gradual smooth boundary.

A2--8 to 19 inches (20 to 48 cm); yellowish red (5YR 5/6) gravelly loam, red (2.5YR 4/6) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; common very fine roots; many very fine, few fine pores; 15 percent gravel; moderately acid (pH 5.6); abrupt wavy boundary. (Combined thickness of the A horizon is 4 to 30 inches, 10 to 76 cm)

2Bt--19 to 22 inches (48 to 56 cm); yellowish red (5YR 4/6) clay, red (2.5YR 4/6) with dark red (2.5YR 3/6) coatings moist; weak medium prismatic structure parting to moderate, medium subangular blocky; extremely hard, extremely firm, sticky and very plastic; few very fine roots, common very fine tubular pores; 10 percent gravel; thick continuous clay films on vertical faces of peds; colloid nearly fills all voids; numerous iron-manganese masses on faces of peds; strongly acid (pH 5.3); abrupt wavy boundary. (3 to 12 inches thick, 8 to 30 cm)

3Bqm--22 to 35 inches (56 to 89 cm); yellowish red (5YR 4/6) duripan; massive, indurated with iron-silica; red (2.5YR 4/6) moist with dark red (2.5YR 3/6) clay films and iron-manganes masses on fracture faces; very few fine pores; 35 percent gravel, very strongly acid in upper part, neutral below.

TYPE LOCATION: Tehama County, California; 0.42 miles north of benchmark 311, about 5 miles south of Red Bluff. 40 degrees, 6 minutes, 17 seconds N latitude and 122 degrees, 13 minutes, 55 seconds W longitude, Gerber Quad.

RANGE IN CHARACTERISTICS: Depth to the duripan is 20 to 40 inches (51 to 102 cm). The mean annual soil temperature is about 62 to 67 degrees F (17 to 19 degrees C). The soil between depths of 4 and 18 inches (10 to 46 cm) is usually dry all of the time from June until September or early October, and is moist in some or all parts all the rest of the year. Weighted average clay content of the upper 20 inches (51 cm) of the argillic horizon is 35 to 60 percent. Some pedons have a BA horizon.

The A horizon has dry colors of 7.5YR 6/4, 6/6, 5/4, 4/4, 5/8, 5/6, 5YR 6/4, 6/3, 5/8, 5/6, 5/4, 5/3, 4/8 or 4/6 and moist color of 7.5YR 4/6, 4/4, 3/4, 3/3 5YR 3/3, 5YR or 2.5YR 3/4, 3/5, 3/6, 4/2, 4/3, 4/4, 4/5, 4/6, 5/4, 5/5 or 5/6, 10YR 3/4. It is loam, sandy loam gravelly sandy loam, gravelly loam, gravelly clay loam, cobbly sandy loam, cobbly loam or cobbly clay loam, sandy clay loam, or gravelly sandy clay loam. Clay content ranges from 10 to 30 percent. Coarse fragments range from 5 to 30 percent. Base saturation (sum) is 35 to 75 percent. Reaction is neutral slightly acid to strongly acid.

Some pedons have a Bt horizon with 18 to 30 percent clay above the 2Bt horizon. Where present, it has dry color of 5YR 5/4, 4/6, 5/6, 5/8, 6/6, 6/8; or 2.5YR or 4/6, 7.5YR 5/4 and moist color of 5YR 3/4, 4/4, 4/6; 2.5YR 3/4, 3/6, 4/6. It is loam, gravelly loam, cobbly loam, sandy clay loam, gravelly sandy clay loam, cobbly sandy clay loam, gravelly clay loam, cobbly clay loam, or clay loam. Content of coarse fragments is 0 to 35 percent with 0 to 15 percent cobbles. Base saturation (SUM) is 35 to 75 percent. It is strongly acid to neutral. The lower boundary is abrupt.

In some pedons a thin E or AB horizon is present above the argillic.

The 2Bt horizon has dry colors of 7.5YR 6/4, 5/6, 5/4, 4/4; 5YR 6/8, 6/6, 5/8, 5/6, 5/4, 4/6, 4/4; 2.5YR 5/8, 5/6, 5/4, 4/8, 4/6 or 4/4 and moist color of 7.5YR 4/4, 4/2; 5YR 3/4, 4/6, 4/4, 4/3; 2.5YR 3/4, 3/6, 4/3, 4/4, 4/6 or 4/8. It is clay loam, clay, gravelly clay loam, gravelly clay, cobbly clay loam or cobbly clay with 35 to 60 percent clay. It has an abrupt upper boundary with an absolute clay increase of 15 to 40 percent. Coarse fragments range from 5 to 35 percent. Base saturation (sum) is 75 to 95 percent. Reaction is strongly acid to slightly acid to neutral.

The 3Bqm horizons have colors of 10YR 7/6, 5/3, 7.5YR 7/6, 4/4, 4/6, 5/4, 5/6, 6/6, 7/4, 7/6; 5YR 4/6, 5/6 or 6/6. Moist color is 10YR 4/3, 3/4; 7.5YR 4/4, 5/4; 5YR 4/6, 4/4, 5/4, 5/6; 2.5YR 3/6, 4/6, or 4/8. Coarse fragments range from 15 to 75 percent. Strength of cementation decreases with depth.

Stratified 2C or 3C horizons underlie the duripan in some pedons.

COMPETING SERIES: These are the Eastbiggs (CA), San Joaquin (CA) and Yuvas (CA) series. Eastbiggs soils have a perched water table (seasonal wetness) above the duripan. San Joaquin soils have base saturation (sum) of 75 to 100 percent in some part of the soil above the argillic. Yuvas soils have a paralithic contact at 20 to 40 inches (51 to 102 cm).

GEOGRAPHIC SETTING: Redding soils are on nearly level or dissected fan remnants. Microrelief may be hummocky. Gravel and cobbles tend to concentrate in the swales in hummocky areas. Vernal pools are common in areas with slopes of 0 to 3 percent. Slopes are 0 to 30 percent. Elevations are 40 to 2,000 feet (12 to 610 m). The soils formed in alluvium of mixed rocks. Climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation is 10 to 35 inches (254 to 889 mm). Average January temperature is 45 degrees F (7 degrees C); average July temperature is 80 degrees F (27 degrees C); mean annual temperature is 60 to 63 degrees F (16 to 17 degrees C). The frost-free season is 230 to 320 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing San Joaquin soils and the Anderson, Auburn, Corning, Kimball, Newton, Newville, Perkins and Red Bluff. San Joaquin soils are on lower, relatively younger terraces. Auburn soils have bedrock at 10 to 20 inches (25 to 51 cm) and are usually on foothills above Redding soils. Anderson soils lack a duripan and are on flood plains. Corning soils lack a duripan and are in similar landscape positions, often in complex with Redding. Kimball soils lack a duripan and are on lower, relatively younger terraces. Newton, Newville, Perkins and Red Bluff soils lack a duripan.

DRAINAGE AND PERMEABILITY: Well or moderately well drained, very low to high runoff, except for local ponding in intermound areas; very slow to slow permeability.

USE AND VEGETATION: Used for rangeland and dryland small grain. A few areas are used for irrigated pasture. Natural vegetation is annual grasses and forbs.

DISTRIBUTION AND EXTENT: Fan remnants along the northern and eastern edge of the Central Valley in California. The soils are extensive in MLRA-17.

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

SERIES ESTABLISHED: Redding Area, California, 1907.

REMARKS: The Redding soils were formerly classified as having kaolinitic mineralogy.



Diagnostic horizons and features recognized in this pedon are:

Ochric epipedon - the zone from the surface to a depth of 19 inches (0 to 48 cm) (A1, A2).

Argillic horizon - the zone from 19 to 22 inches (48 to 56 cm)(2Bt).

Duripan - the zone from 22 to 35 inches (56 to 89 cm) (3Bqm).

Abruptic subgroup - the argillic horizon has an abrupt upper boundary with an absolute clay increase of 15 to 40 percent.

Edit log: 5/04/2003 edits for use in Butte County: change hardpan to duripan, expand thickness of the A horizon from 10 to 4 inches; Range in Characteristics-added some pedons have a BA horizon, to the A horizon added 7.5YR 4/6, 3/3, and 10YR 3/4 moist, added sandy clay loam or gravelly sandy clay loam; expanded reaction from slightly acid to neutral; in the Bt horizon added 7.5YR 5/4 dry, 5YR 4/6, 2.5YR 3/4 moist, added gravelly loam, cobbly loam, sandy clay loam, gravelly sandy clay loam, cobbly sandy clay loam, gravelly clay loam, and cobbly clay loam, expanded reaction from slightly acid to neutral; in the 2 Bt horizon expanded reaction from slightly acid to neutral; in the 3 Bqm added 10YR 3/4 moist; Drainage and Permeability; expand range to include very slow to slow permeability. In Butte County, Redding will be used only on mounds.

Edits made after sdjr projects - AEC

ADDITIONAL DATA: Data from the type location (sampled as reference project) established mineralogy as mixed. Redding mapped in San Diego County is outside the range for the series.

Other lab data to support this classification are samples S45CA-57-005 and S79CA-067-001. This data is in the NSSL data base. NSSL pedon S45CA-103-005 is the type location. Typical pedon for Northen Stanislaus Soil Survey area was NSSL pedon 05N0393.

National Cooperative Soil Survey
U.S.A.