LOCATION CHAIX CA
Established Series
Rev. JHR/GLA/DJE/AJT
09/2025
CHAIX SERIES
The Chaix series consists of moderately deep, somewhat excessively drained soils that formed in material weathered from acid intrusive igneous rock, mainly granite or granodiorite. Chaix soils are on mountains and have slopes of 5 to 75 percent. The mean annual precipitation is about 40 inches and the mean annual temperature is 54 degrees F.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Dystroxerepts
TYPICAL PEDON: Chaix coarse sandy loam - on a 35 percent south facing slope under ponderosa pine, sugar pine, incense-cedar, black oak, bear clover and manzanita at about 4,300 feet. (Colors are for dry soil unless otherwise stated.)
Oi--0 to 1 inches (0 to 3 cm); leaf litter.
A1--1 to 4 inches (3 to 10 cm); grayish brown (10YR 5/2) coarse sandy loam, very dark grayish brown (10YR 3/2) moist; weak medium granular structure; slightly hard, very friable, nonsticky and nonplastic; common very fine and fine roots; many very fine interstitial and few very fine tubular pores; moderately acid (pH 6.0); abrupt smooth boundary. (2 to 4 inches thick)
A2--4 to 6 inches (10 to 15 cm); brown (10YR 5/3) coarse sandy loam, dark brown (10YR 3/3) moist; weak fine granular structure; slightly hard, friable, nonsticky and nonplastic; common fine and few medium roots; many very fine interstitial and few very fine and fine tubular pores; moderately acid (pH 6.0); clear smooth boundary. (1 to 3 inches thick)
Bw--6 to 14 inches (15 to 36 cm); light yellowish brown (10YR 6/4) coarse sandy loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine, common fine and many medium and coarse roots; many very fine interstitial and few very fine tubular pores; strongly acid (pH 5.5); gradual smooth boundary. (7 to 10 inches thick)
BC--14 to 31 inches (36 to 79 cm); very pale brown (10YR 7/3) coarse sandy loam, light yellowish brown (10YR 6/4) moist; massive; slightly hard, friable, nonsticky and nonplastic; few very fine and fine and common medium and coarse roots; many very fine interstitial pores; strongly acid (pH 5.5); clear wavy boundary. (10 to 23 inches thick)
Cr--31 to 49 inches (79 to 124 cm); brownish and whitish weathered granitic rock; mineral grains retaining original rock structure.
TYPE LOCATION: El Dorado County, California; 2 miles west of Kyburz; 100 feet north or uphill from Weber Mill Road, about .75 miles west of intersection with U.S. 50; 0.3 miles northeast of the SW corner section 29, T.11 N., R.15 E.
RANGE IN CHARACTERISTICS: The soils are 20 to 40 inches deep to a paralithic contact of weathered granitic rock. The soil between a depth of about 10 to 30 inches becomes dry in all parts sometime in June or the first few days of July and remains dry until sometime in October. The mean annual soil temperature is 47 to 59 degrees F. The base saturation in the upper 30 inches ranges from 15 to 60 percent. The soil is coarse sandy loam or sandy loam. Clay content averages 5 to 15 percent. Gravel and cobbles range from 1 to 25 percent.
The A horizon is 10YR 3/3, 4/2, 4/3, 5/2, 5/3, 6/2, 6/3, 6/4, 7/2, 7/3. Moist color is 10YR 3/1, 3/2, 3/3, 4/2, 4/3, 4/4. Some pedons have thin 2.5Y 5/2 and 10YR 3/1 moist A1 horizons. It contains 2 to 6 percent organic matter. This horizon has weak or moderate granular structure. It is slightly acid or strongly acid.
The Bw horizon has dry colors of 10YR 5/3, 5/4, 5/6, 6/3, 6/4, 7/1, 7/3, 7/4; 2.5Y 6/4 or 7/4. Moist colors are 10YR 3/4, 4/2, 4/3, 4/4, 5/3, 5/4 or 5/6. The chroma and/or value is at least one unit higher than the A horizon. It has 0.25 to 0.95 percent organic matter. It is slightly acid through strongly acid.
Some pedons have a C horizon with dry colors of 10YR 6/2, 6/3, 6/4, 7/2, 7/3, 7/4, 8/2, 8/3, or 8/4.
The Cr horizon is strongly weathered granitic rock that is easily dug by hand tools but retains the original rock structure. Root penetration is restricted with only a few extending along joints or fractures.
COMPETING SERIES: These are the
Dome,
Siskiyou,
Sitkum,
Steinmetz,
Tethrick, and
Ulricher series. Dome, Steinmetz, Tethrick, and Ulricher soils are all greater than 40 inches deep. Siskiyou soils have a mean annual temperature of 45 to 54 degrees F. Sitkum soils (MLRA 5) have a mean annual temperature of 45 to 52 degrees F and are dry for less than 90 consecutive days.
GEOGRAPHIC SETTING: Chaix soils are on mountain slopes. Slopes are 5 to 75 percent. The soils formed from quartz diorite and granodiorite low in mafic materials. Elevations are 1,200 to 6.500 feet. The climate is moist subhumid with warm dry summers and cold moist winters. Mean annual precipitation is 25 to 70 inches. Seasonal snowfall is 20 to 100 inches. Mean annual temperature is about 48 to 58 degrees F. Mean January temperature is about 39 degrees F; mean July temperature is about 70 degrees F. Frost-free season is about 100 to 225 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Chawanakee,
Hoda,
Holland,
Musick,
Shaver, and
Tollhouse soils. Hoda, Holland and Musick soils have an argillic horizon. Chawanakee and
Hotaw soils occur on similar positions on ridges and mountain slopes. Holland and Shaver soils occur on backslope positions of mountain slopes. Musick soils occur on stable summits, backslopes and ridges. Tollhouse soils are shallow, occur on steep mountain slopes, and are associated with rock outcrop.
DRAINAGE AND PERMEABILITY: Somewhat excessively drained; slow to very rapid runoff; moderately rapid permeability.
USE AND VEGETATION: Used mainly for timber production with limited browse for livestock. Native vegetation is ponderosa pine, incense-cedar, sugar pine Douglas-fir, black oak, canyon oak and mountain shrubs.
DISTRIBUTION AND EXTENT: The middle mountain area of the Sierra Nevada Mountains and Shasta, Trinity and Siskiyou counties of northern California, MLRA 22A.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Nevada County Area, California 1969.
REMARKS: The Fidalgo, Kickerville and Siskiyou series descriptions are old and not properly defined to adequately differentiate.
09/2025--Competing series checked and updated. -JBB
ADDITIONAL PEDON: NSSL pedon S77CA-019-001 and one in Tuolumne County (Stanislaus NF): S90CA-109-119 (taxadjunct)
National Cooperative Soil Survey
U.S.A.