LOCATION INKS                    CA

Established Series
Rev. SBJ/JHR/TDC/GMK/ET/AEC
03/2018

INKS SERIES

The Inks series consists of shallow, well drained soils that formed in material weathered from consolidated or cemented sediments from volcanic rocks. These soils are on undulating to hilly tabular volcanic ridges and sideslopes. The mean annual precipitation is about 30 inches and the mean annual air temperature is about 60 degrees F.

TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, thermic, shallow Ultic Argixerolls

TYPICAL PEDON: Inks very cobbly sandy clay loam, rangeland. (Colors are for dry soil unless otherwise noted.)

A--0 to 6 inches (0 to 15 cm); brown (10YR 5/3)very cobbly sandy clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and nonplastic; many very fine roots; many very fine pores; 20 percent gravel, mostly larger than 1/2 inch and 15 percent cobbles; moderately acid (pH 5.9); clear irregular boundary. (5 to 12 inches thick)

BAt--6 to 10 inches (15 to 25 cm); brown (10YR 5/3)very gravelly clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, friable, sticky and slightly plastic; common very fine roots; many very fine pores; thin, nearly continuous clay films on all face of peds and in pores; 35 percent gravel and 20 percent cobbles; moderately acid (pH 5.9); clear irregular boundary. (3 to 8 inches thick)

Bt--10 to 13 inches (25 to 33 cm); brown (10YR 4/3)very cobbly loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, firm, sticky and slightly plastic; common very fine roots; common very fine pores; thin continuous clay films on all faces of peds, in pores, and as bridges between sand grains; 10 percent gravel mostly 1/2 to 2 inches, and 25 percent cobbles; moderately acid (pH 5.9); abrupt irregular boundary. (0 to 6 inches thick)

2Cr--13 to 18 inches (33 to 46 cm); partly weathered weakly consolidated tuff from basic igneous rock sources; few roots in cracks.

TYPE LOCATION: Tehama County, California; about 3 miles northwest of Dales in the SW1/4 of the NE1/4 of sec. 30, T.29N., R.2W. 40 degrees 20 minutes 16.3 seconds North 122 degrees 7 minutes 23 seconds West, NAD83

RANGE IN CHARACTERISTICS: Depth to a paralithic contact is 10 to 20 inches. The mean annual soil temperature is about 60 degrees to 65 degrees F. and the soil temperature usually is not below 47 degrees F. at any time. The soil between depths of 4 to 20 inches is usually dry all of the time from June until October and is moist in some or all parts all the rest of the year. Coarse fragments make up 15 to 50 percent of the A horizon and 35 to 70 percent of the B horizon.

The A horizon is brown, dark brown, or yellowish brown in 10YR or 7.5YR hue and has value of 3, 4, or 5 dry, 2 or 3 moist, and chroma of 2, 3, or 4 dry and 2 or 3 moist. It is sandy clay loam, loam or fine sandy loam and is very cobbly, gravelly or cobbly. This horizon has granular or subangular blocky structure or it is massive. It ranges from soft to hard but is only slightly hard when massive. It is neutral to moderately acid.

The BAt and Bt horizons are light brown, brown, dark brown, strong brown, or reddish brown and has dry value of 3, 4, or 5 in 10YR or 7.5YR hue and 4 or 5 in 5YR hue. Chroma is usually 3 in 10YR hue, 2, 4, or 6 in 7.5YR hue, and 3 or 4 in 5YR hue. This horizon is loam or clay loam and is gravelly or very gravelly or very cobbly. It is neutral to moderately acid and commonly the reaction is constant in all horizons or the acidity increases slightly as depth increases.

COMPETING SERIES: These are the Exchequer, Friant, Pentz, Supan, Toomes, and Tuscan series. Exchequer, Pentz, and Toomes soils have ochric epipedons and lack argillic horizons. Also, Pentz soils are loamy. Friant soils lack argillic horizons. Supan soils have mollic epipedons more than 20 inches thick and have mesic soil temperatures. Tuscan soils have ochric epipedons, fine argillic horizons and duripans.

GEOGRAPHIC SETTING: Inks soils are on undulating to hilly tabular volcanic ridges and their side slopes associated with the Mehrten Formation and on rounded hills and steep slopes associated with Tuscan Formation sediments. Slopes are 2 to 50 percent. Elevations are 200 to 2,000 feet. These soils formed in colluvium and residuum from consolidated or cemented sediments from volcanic rocks. The underlying material is tuff, breccia, or conglomerate. The climate is subhumid mesothermal with hot, dry summers and cool, moist winters. Mean annual precipitation is 20 to 40 inches. Average January temperature is 46 degrees F.; average July temperature is 81 degrees F.; mean annual temperature is 58 degrees to 62 degrees F. The freeze-free season is 175 to 270 days.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Exchequer, Pentz, Supan, Toomes, ant Tuscan soils and the Guenoc, Keefers, Lobitos, and Montara soils. Guenoc soils have ochric epipedons and have fine argillic horizons with 2.5YR or 10R hue. Keefers soils have clayey-skeletal control sections, ochric epipedons, and lack a lithic or paralithic contact. Lobitos soils lack a lithic contact at depths of less than 20 inches and have mesic soil temperature. Montara soils lack argillic horizons and have serpentinitic mineralogy.

DRAINAGE AND PERMEABILITY: Well drained; medium or rapid runoff; moderate permeability.

USE AND VEGETATION: Used for grazing. Natural vegetation is mainly oaks with scattered digger pine, ceanothus, manzanita, poison oak, and annual grasses and forbs.

DISTRIBUTION AND EXTENT: The soils occur on lower slopes of the Cascade and Sierra Nevada Ranges in northern California. The soils are moderately extensive.

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

SERIES ESTABLISHED: Tehama County, California, 1962.

REMARKS: The Inks soils were formerly classified as Noncalcic Brown soil.

The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET

OSED scanned by SSQA. Last revised by state on 2/75.

Edits made after sdjr projects and the reassessment of the OSD profile:
The lithologic discontinuity was applied to the now paralithic contact to represent the gravelly and cobbly soil that is typically colluvium remobilized from the alluvium of the Red Bluff Formation over the underlying tuffaceous sediments in the Inks extent in Tehama County. Lab PSA results for the OSD profile from site ID S1955-CA-52-011 were incorporated with OSD profile rock fragment amounts for texture edits.
The R horizon in Inks in Placer County was retained as a lithic contact at this point and the Lithic Argixerolls classification was not changed. If the Lithic contact is verified by field verification in Placer and Amador counties, the reference to tabular ridges of the Mehrten Formation should be excluded. - AEC

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National Cooperative Soil Survey
U.S.A.