LOCATION EXCHEQUER CAEstablished Series
TAXONOMIC CLASS: Loamy, mixed, superactive, nonacid, thermic Lithic Xerorthents
TYPICAL PEDON: Exchequer silt loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A11--0 to 1.5 inches; yellowish red (5YR 5/6) silt loam, reddish brown (5YR 5/4) moist; massive; hard, friable, nonsticky and slightly plastic; many fine and very fine roots; many fine pores; slightly acid (pH 6.3); clear smooth boundary. (1 to 5 inches thick)
A12--1.5 to 10 inches; yellowish red (5YR 5/8) silt loam, yellowish red (5YR 5/6) moist; massive; hard, friable, nonsticky and slightly plastic; common fine and very fine roots; common fine pores, 10 percent platy rock fragments; slightly acid (pH 6.1); abrupt broken boundary. (3 to 17 inches thick)
R--10 inches; greenish hard meta - andesitic schist with near vertical dip to schistosity; upper two inches weathered on surfaces to yellow (10YR 8/6) with small amounts of yellowish red fine earth in cracks.
TYPE LOCATION: Merced County, California; 1/2 mile south of the north edge of sec. 12, T.4S., R.14E., on the east side of the road through the section.
RANGE IN CHARACTERISTICS: Depth to a lithic contact is 4 to 20 inches. The mean annual soil temperature is a 62 to 65 degrees F. and the soil temperature usually is not below 47 degrees at any time. The soil between depths of about 4 and 12 inches is usually dry all of the time from late April until November and is moist in some or all parts all the rest of the year. Rock fragments are predominantly less than 3 inches in diameter and make up 5 to 30 percent of the soil volume. Fragments are more numerous in the lower part of the profile. Reaction is from slight to moderately acid.
The A horizon has hue of 10YR, 7.5YR or 5YR, value to 3 through 5 and moist chroma of 4 through 8. Some pedons have a thin A11 with a chroma of 2. It is loam or silt loam and has up to 30 percent pebbles and cobbles. Structure is weak granular and subangular blocky or the soil is massive.
COMPETING SERIES: These are the Daulton, Friant, Gaviota, Trigo and Whiterock series. Daulton soils have ochric epipedons with moist value of 3, chroma of 2 or 3 moist throughout and are massive and hard when dry. Friant soils have mollic epipedons. Gaviota soils have epipedons with chroma of 3 or less moist and have more than 50 percent sand in the fine earth fraction. Trigo soils have a paralithic contact at depths of less than 20 inches. Whiterock soils are strongly or very strongly acid and have epipedons that have value higher than 5.
GEOGRAPHIC SETTING: Exchequer soils are on undulating to steep uplands at elevations of 400 to 2,000 feet. They formed in residuum from hard andesitic breccia, schist and metamorphosed volcanic rocks. The climate is subhumid mesothermal with warm summers and moist cool winters. Mean annual precipitation is 15 to 35 inches. Average January temperature is 44 to 51 degrees F.; average July temperature is 74 to 78 degrees F.; mean annual temperature is 59 to 64 degrees F. The frost-free season is 220 to 270 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Daulton and Whiterock soils and the Auburn, Inks and Toomes soils. Auburn and Toomes soils have cumbic horizons. Inks soils have argillic horizons.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; medium to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for rangeland. The vegetation is annual grasses with small herbaceous plants, scattered blue oaks; or dense shrubs.
DISTRIBUTION AND EXTENT: Lower foothills of the western Sierra Nevada of central and north-central California and coastal hills of southern California. The soils are moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Merced County (Merced Area), California 1959.
REMARKS: This soil would have been classified as a Lithosol.
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.