LOCATION SPRECKELS CA
Tentative Series
Rev. SBJ-LCL-ET
02/2023
SPRECKELS SERIES
The Spreckels series is a member of the fine, mixed, mesic family of Ultic Palexeralfs. Spreckels soils have grayish brown and light brownish gray slightly acid, loamy A horizons; brown, strongly acid clay B2t horizons; and brown very gravelly clay C horizons.
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Ultic Palexeralfs
TYPICAL PEDON: Spreckels loam - rangeland (Colors are for dry soil unless otherwise stated)
A11--0 to 9 inches; grayish brown (10YR 5/2) loam, very dark gray (10YR 3/1) moist; moderate fine and medium subangular blocky structure; slightly hard, friable, slightly sticky, slightly plastic; common fine and very fine roots; common fine tubular, many fine and very fine interstitial pores; slightly acid (pH 6.5); clear smooth boundary. (6 to 10 inches thick)
A12--9 to 18 inches; light brownish gray (10YR 6/2) clay loam, very dark grayish brown (10YR 3/2) moist; moderate medium and coarse subangular blocky structure; hard, friable, sticky, plastic; common coarse medium and fine roots; common fine tubular and many very fine and fine interstitial pores; slightly acid (pH 6.5); abrupt smooth boundary. (6 to 12 inches thick).
B21t--18 to 29 inches; brown (10YR 5/3) clay, dark yellowish brown (10YR 4/4) and brown (10YR 4/3) moist; massive; very hard, very firm, sticky, plastic; common coarse roots; common very fine discontinuous tubular pores; continuous thick clay films on ped faces, as bridges; strongly acid (pH 5.5); clear wavy boundary. (10 to 13 inches thick)
B22t--29 to 37 inches; brown (10YR 5/3) and pale brown (10YR 6/3) clay, brown (10YR 4/3) moist; massive; extremely hard, firm, sticky, plastic; few very fine and fine, common coarse roots; common very fine pores; continuous moderately thick clay films on ped faces, in pores and as bridges; strongly acid (pH 5.5); gradual wavy boundary. (10 to 13 inches thick)
C1--37 to 60 inches; brown (10YR 5/3) and yellowish brown (10YR 5/6) very gravelly clay loam, dark yellowish brown (10YR 5/5) moist, no roots or pores, few thin clay films on gravels; moderately acid (pH 5.7).
TYPE LOCATION: Sonoma County, California, one mile east of junction of Leslie Road and Chalk Hill road in the NE1/4 of the NW1/4 of Section 16, T. 8 N., R. 6 W.
RANGE IN CHARACTERISTICS: In some pedons, there are lenses of cemented tuffaceous sediments below the B2t horizon. Solum thickness and depth to the very gravelly substratum are 22 to 36 inches. Soil temperature is 53 to 56 degrees F., and mineralogy is mixed. The soils become dry in the moisture control section about June 5 and remain dry until about October 1. At other times the soils are moist.
The A horizons have colors with 10YR hues, values of 5 or 6 dry and 3 or 4 moist, and chromas of 1 through 4. Texture is sandy loam or clay loam. Structure is moderate granular, moderate subangular blocky or the soils are massive. Consistence is slightly hard or hard, friable, nonplastic, slightly plastic or plastic, nonsticky, slightly sticky or sticky. Reaction is slightly acid or neutral.
The B2t horizon colors have 10YR hues, values of 5 or 6 dry and 4 moist, and chromas of 2, 3, or 4. Textures are clay or heavy clay loam and reaction is strongly acid to medium acid.
The C horizons have colors with hues of 10YR, values of 5 through 7 and chromas of 2 and 3 dry, and 2 moist. Textures are very gravelly clay loam or heavy loam. Reaction is moderately acid.
COMPETING SERIES: These include the
Clough,
Fiddyment,
Haire,
Hillgate,
Huichica,
Milpitas,
Millsap,
Pinnacles,
San Ysidro, and
Santa Ynez series. Clough soils have very gravelly clay B2t horizons and a duripan at 29 inches. Fiddyment soils have a gradual AB boundary and a slightly acid B2t horizon. Haire soils have a very gravelly clay IIC horizon at 36 inches, and Hillgate soils have neutral B2t horizons. Huichica soils have a moderately acid B2t horizon and a duripan at 30 inches. Milpitas soils have slightly acid and neutral B2t horizons and Millsap soils have slightly acid B2t horizons and an R layer at 39 inches. Pinnacles soils have a sandy clay B2t horizon and a paralithic layer at 25 inches. San Ysidro soils have slightly acid and neutral B2t horizons, and Santa Ynez soils have A2 horizons and gravelly and very gravelly B2t horizons.
GEOGRAPHIC SETTING: Spreckels soils occur on sloping to hilly uplands of tuffaceous sediments. They occur at elevations of 100 to 800 feet, in a subhumid mesothermal climate with mean annual rainfall of 25 to 30 inches, with hot dry summers and cool moist winters. Mean annual temperature is about 55 degrees F., average January temperature about 46 degrees F., and average July temperature about 64 degrees F. Frost free season averages about 210 days.
GEOGRAPHICALLY ASSOCIATED SOILS: The
Haire and
Huichica soils, the moderately deep Butte soils, and the very shallow
Toomes soils.
DRAINAGE AND PERMEABILITY: Well drained with slow permeability and medium runoff.
USE AND VEGETATION: Used mostly for grazing. Natural vegetation is Oaks, madrone, manzanita, poison oak and grasses.
DISTRIBUTION AND EXTENT: Sonoma County, and Shasta County, California and possibly in other nearby counties. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES PROPOSED: Sonoma County Area, 1964.
REMARKS: This series formerly would have been classified in the Nonclacic Brown group.
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 12/69.
National Cooperative Soil Survey
U.S.A.