LOCATION JIGGS                   CA

Established Series
Rev. RCH


The soils have thin, grayish brown to light brownish gray, medium acid, gravelly sandy loam A1 horizons; light gray, strongly acid,gravelly sandy loam B2 horizons that grade into fractured hard rhyolite bedrock at about 2 feet.

TAXONOMIC CLASS: Medial, mixed, frigid Typic Vitrixerands

TYPICAL PEDON: Jiggs gravelly sandy loam - forested. (Colors for dry conditions unless otherwise noted.)

Oi/Oe--0 to 1 inches; Forest floor composed of fresh and matted needles, leaves, and small twigs in the upper part and grades into a thin layer of partly decomposed organic matter; abrupt smooth boundary. (1 to 2 inches thick).

A1--1 to 3 inches; grayish brown (10YR 5/2) gravelly sandy loam, very dark brown (10YR 2/2) moist; moderate medium granular structure; soft, friable, nonsticky, nonplastic; few very fine roots; many very fine and fine, few medium and coarse interstitial pores; medium acid; abrupt wavy boundary. (2 to 4 inches thick).

A3--3 to 7 inches; light brownish gray (10YR 6/2) gravelly coarse sandy loam, brown (10YR 4/3) moist; moderate medium granular structure; soft, friable, nonsticky, nonplastic; abundant very fine and fine, plentiful medium, few large roots; many very fine to medium, few large pores; white mycelia common; medium acid; clear wavy boundary. (4 to 9 inches thick).

B2--7 to 21 inches; light gray (10YR 7/2) gravelly coarse sandy loam, grayish brown (10YR 5/2) moist; weak medium subangular blocky structure; slightly hard, friable, nonsticky, nonplastic; abundant very fine and fine, plentiful medium roots; many very fine to medium pores; strongly acid; clear irregular boundary. (12 to 20 inches thick).

B2/R--21 inches +; weathered and fractured hard rhyolitic rock with the interstices partially filled with soil material similar to the horizon above; few medium and large sized roots extend into this horizon to an undetermined depth; many feet thick.

TYPE LOCATION: Tehama County, California. On the NW slope of Dry Gulch between Blue Ridge and Forward Mill in the SE1/4 of Sec. 30, T. 30 N., R. 3E.

RANGE IN CHARACTERISTICS: The soils have ochric epipedons, cambic horizons, lithic contact; usually dry in all parts of 10 to 40 inch section; have soil temperatures less than 47 degrees F.; the solum is 18 to 30 inches thick. Depth to fractured bedrock ranges from 18 to 60 inches, usually 20 to 36 inches. The A1 horizons range in color from light gray to grayish brown (10YR 6/1, 6/2, 5/3, 5/2; 2.5Y 6/2, 5/1) dry and dark grayish brown to dark brown moist; in texture from gravelly sandy loam to gravelly loam and in reaction from neutral to strongly acid. The A3 horizon is medium to very strongly acid. The B2 horizons range in color from pale brown to very pale brown, light gray and white (10YR) dry and pale brown to grayish brown moist; in texture from gravelly sandy loam to gravelly sandy clay loam and in reaction from medium acid to strongly acid.

COMPETING SERIES: These include the Butte, Cone, Forward, Kidd, Laniger, and Lyonsville series. The Butte soils have fine loam Bt horizons and are ashy. The Cone soils are very gravelly loam throughout and are mesic. The Forward soils have very pale brown cambic horizons and are ashy. The Kidd soils are about 15 inches deep to rock and are thermic. The Laniger are dark colored throughout and are ashy and thermic. The Lyonsville soils have fine loamy cambic horizons.

GEOGRAPHIC SETTING: The Jiggs soils occur on sloping to steep mountainous uplands. Underlying rock is rhyolite. Elevations are 3,000 to 6,000 feet. The climate is moist subhumid mesothermal with mean annual rainfall of 45 to 55 inches, with warm nearly dry summers and cold wet winters. Mean annual temperature is about 45 degrees F., average January temperature about 32 degrees F., and average July temperature about 65 degrees F.

GEOGRAPHICALLY ASSOCIATED SOILS: Jiggs soils occur in the same general area as the Cohasset, Forward, Kidd and Spreckels soils.

DRAINAGE AND PERMEABILITY: Somewhat excessively drained to well drained, permeability is moderately rapid or rapid, and runoff is slow to medium.

USE AND VEGETATION: Used for timber production. Vegetation includes ponderosa pine, sugar pine, incense cedar, Douglas fir, white fir, Ceanothus, manzanita and oaks.

DISTRIBUTION AND EXTENT: Cascade Range and Coast Ranges of Northern California. The soils are moderately extensive.


SERIES ESTABLISHED: Soil survey of Tehama County, California, 1962. Name from Jiggs Ranch in Tehama County.

REMARKS: The Jiggs series was formerly classified in the Regosol group.

OSED scanned by SSQA. Last revised by state on 7/14/66.

National Cooperative Soil Survey