LOCATION CENTENNIAL CA
Established Series
Rev. AFF/ET/CEJ/MAV
04/2015
CENTENNIAL SERIES
The Centennial series consists of moderately deep, well drained soils formed in alluvium weathered from mixed sources including calcareous lacustrine sediments. Centennial soils are on fan terraces. Slope is 2 to 9 percent. The mean annual precipitation is about 6 inches and the mean annual temperature is about 59 degrees F.
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, thermic Argic Petrocalcids
TYPICAL PEDON: Centennial loamy sand, on a south facing slope of 3 percent under shadscale, bud sagebrush, and spiny menodora at an elevation of 3,980 feet. (When described on May 9, 1983 the soil was dry to 6 inches and slightly moist below to the hardpan. Colors are for dry soil unless otherwise stated).
A1--0 to 1 inch; light brownish gray (2.5Y 6/2) loamy sand, brown (10YR 4/3) moist; moderate medium and thick platy structure; soft, very friable, nonsticky and nonplastic; few very fine roots; common very fine and fine interstitial and common medium vesicular pores; slightly effervescent; 10 percent angular and subrounded pebbles; moderately alkaline (pH 8.1); abrupt wavy boundary. (1 to 2 inches thick)
A2--1 to 6 inches; light brownish gray (2.5Y 6/2) loamy sand, brown (10YR 4/3) moist; weak fine and medium subangular blocky structure; soft, very friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine and fine interstitial and common fine and medium tubular pores; slightly effervescent; 5 percent angular and subrounded pebbles, moderately alkaline (pH 8.2); gradual wavy boundary. (0 to 5 inches thick)
Btk1--6 to 16 inches; light yellowish brown (2.5Y 6/4) loamy sand, light olive brown (2.5Y 5/4) moist; moderate medium and coarse subangular blocky structure; slightly hard, friable, nonsticky and nonplastic; common very fine, fine and medium roots; common very fine and fine interstitial and common fine and medium tubular pores; few thin clay films bridging mineral grains; strongly effervescent; carbonates segregated as common fine concretions and soft masses; 10 percent angular and subrounded pebbles and 2 percent cobbles; moderately alkaline (pH 8.4); clear irregular boundary. (2 to 15 inches thick)
Btk2--16 to 22 inches; light yellowish brown (10YR 6/4) sandy loam, yellowish brown (10YR 5/4) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine, fine and medium roots; common very fine interstitial and common fine and medium tubular pores; common thin clay films bridging mineral grains and few thin clay films on peds; strongly effervescent carbonates segregated as common fine concretions and soft masses; 10 percent angular and subrounded pebbles and 2 percent cobbles, moderately alkaline (pH 8.4); abrupt irregular boundary. (7 to 18 inches thick)
2Bkml--22 to 29 inches; variegated light gray (2.5Y 7/2) and white (10YR 8/1) fractured petrocalcic horizon, variegated light yellowish brown (2.5Y 6/4), and white (10YR 8/1) moist; indurated laminar carbonate layers (18 to 75 mm thick) make up 60 percent of the volume and the remaining matrix is weakly to strongly cemented loamy sand with disseminated carbonates and segregated masses; fractures are 5 to 30 cm apart and less than 2 mm wide; the weakly to strongly cemented loamy sand matrix is massive and very hard; few very fine, fine and medium roots in fractures; strongly effervescent, carbonates segregated in many medium and large seams and masses; strongly alkaline (pH 8.6); gradual irregular boundary. (6 to 10 inches thick)
2Bkm2--29 to 60 inches; variegated light gray (2.5Y 7/2) and white (10YR 8/1) strongly cemented loamy sand, variegated light yellowish brown (2.5Y 6/4), and white (10YR 8/1) moist; indurated laminar carbonate layers make up 50 percent of the volume; few very fine, fine and medium roots in fractures; strongly effervescent, carbonates segregated in many medium and large seams and masses; strongly alkaline (pH 8.8).
TYPE LOCATION: Inyo County, California; about 7 miles southeast of Olancha; 1.6 miles south of Cactus Flat Road on dirt road and 150 feet southwest of dirt road; 1,100 feet east and 2,600 feet south from the NW corner of section 14., T.20 S., R.37 E., Haiwee Reservoir quadrangle.
RANGE IN CHARACTERISTICS: Depth to petrocalcic is 20 to 40 inches. The mean annual soil temperature is 61 to 65 degrees F. The soil temperature is below 47 degrees F. from about December 1 to March 1 and is below 41 degrees F. from about January 1 to February 1. The soil between the depths of 11 and 22 inches is dry throughout for 210 days to 235 days from about May 1 to December 15. It is moist throughout for 40 to 60 days from about January 15 to March 15 and is moist in some or all parts for 40 to 60 consecutive days from about March 1 to May 1 when the soil temperature exceeds 47 degrees F. The surface is covered with 10 to 15 percent subangular and subrounded (2 to 50 mm) gravel. It is slightly effervescent to violently effervescent with disseminated carbonates throughout. Electrial conductivity is 2 to 8 dS/m throughout. Reaction is slightly alkaline to strongly alkaline throughout.
The A horizon color is 2.5Y 6/2, 7/2; 10YR 6/2, 6/3, 7/2, or 7/3. Moist color is 2.5Y 4/4, 5/2, 5/3, 5/4; 10YR 4/3, 4/4, 5/2, or 5/3. It averages 3 to 6 percent clay. It has 5 to 15 percent fine and coarse (2 to 50 mm) gravel.
The Btk1 horizon color is 2.5Y 6/4, 7/2; 10YR 6/4, 7/3 or 7/4. Moist color is 2.5Y 4/4, 5/4; 10YR 4/4, 5/3, or 5/4. It is loamy sand, gravelly loamy sand or sandy loam averaging 3 to 10 percent clay. It has 5 to 30 percent coarse fragments with 5 to 30 percent (2 to 75 mm) gravel and 0 to 5 percent (75 to 150 mm) cobbles. Carbonates are segregated as soft masses or concretions.
The Btk2 horizon color is 2.5Y 6/4, 7/2; 10YR 6/4, 7/3 or 7/4. Moist color is 2.5Y 4/4, 5/4; 10YR 4/4, 5/4 or 6/4. It is sandy loam, gravelly sandy loam or cobbly sandy loam averaging 10 to 18 percent clay. It has 5 to 30 percent coarse fragments with 5 to 25 percent (2 to 75 mm) gravel and 0 to 10 percent (75 to 150 mm) cobbles. Carbonates are segregated as soft masses or concretions.
The 2Bkm horizon color is N8/0; 2.5Y 6/4, 7/2, 7/4, 8/2; 10YR 6/4, 7/2, 7/4, 8/1, or 8/2. Moist color is 2.5Y 5/4, 6/4, 8/2; 10YR 5/4, 6/4, 8/1, or 8/2. It is commonly fractured with a few roots extending down fractures, but in some pedons it is not fractured or has been recemented. Indurated laminar layers make up about 50 to 90 percent of the volume of the upper horizon. Weakly to strongly cemented loamy sand and sand make up the lower part.
COMPETING SERIES: This is the
Hueco series. Hueco soils do not have rock fragments above the petrocalcic horizon, are moist in the summer, and have 5YR hues.
GEOGRAPHIC SETTING: Centennial soils are on fan terraces. Slopes are 2 to 9 percent. The soils formed in alluvium weathered from mixed sources including lacustrine deposits of indurated calcareous sandstone, siltstone, limestone and reworked tuffaceous sediments. Elevations are 3,800 to 4,600 feet. The climate is arid with hot dry summers and cool, moist winters. Mean annual precipitation is 5 to 6 inches. Mean January temperature is about 40 degrees F; mean July temperature is about 81 degrees F.; mean annual temperatures is 57 to 61 degrees F. Frost free season is 215 to 235 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Helendale,
Neuralia and
Timosea (T) soils. Helendale soils do not have a petrocalcic horizon. Neuralia soils are fine-loamy and do not have a petrocalcic horizon. Timosea soils are loamy-skeletal and do not have a petrocalcic horizon. All of these soils are on fan terraces of nearby landscapes.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderately rapid permeability above the petrocalcic horizon and moderately slow to very slow in the petrocalcic horizon.
USE AND VEGETATION: Centennial soils are used for rangeland and wildlife habitat. Vegetation is shadscale, bud sagebrush, spiny menodora, white bursage and desert needlegrass.
DISTRIBUTION AND EXTENT: Southern Owens Valley of eastern California. The series is not extensive. In MLRA 30.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: PHOENIX, ARIZONA
SERIES PROPOSED: Benton-Owens Valley Area, Inyo County, California, 1986. Name from nearby Centennial Flat.
REMARKS: Diagnostic horizons and features recognized in the profile are:
1. Ochric epipedon - The zone from the surface of the soil to 6 inches (A1 and A2 horizons).
2. Argillic horizon - The zone from 6 to 22 inches (ABtk and Btk horizons).
3. Petrocalcic horizon - The zone from 22 to 60 inches (2Ckml and 2Ckm2 horizons).
Responsibility for this series was transferred from Davis to Phoenix 4/2015. The last revision to the series was 2/1997. ET
National Cooperative Soil Survey
U.S.A.