LOCATION CROPLEY CAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, thermic Aridic Haploxererts
TYPICAL PEDON: Cropley clay, formerly tilled but not irrigated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 7 inches; very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; weak medium subangular blocky and strong medium and fine granular structure; very hard, very firm, very sticky and very plastic; many very fine roots; many fine and very fine interstitial and tubular pores; neutral (pH 7.0); clear smooth boundary. (4 to 8 inches thick)
Bss1--7 to 14 inches; very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; strong coarse prismatic structure with few medium and fine granules; very hard, very firm, very sticky and very plastic; few very fine and coarse roots; few fine interstitial and tubular pores; many small slickensides; neutral (pH 7.0); gradual wavy boundary. (6 to 9 inches thick)
Bss2--14 to 36 inches; very dark gray (10YR 3/1) clay, black (10YR 2/1) moist; massive; very hard, very firm, very sticky and very plastic; few fine interstitial and tubular pores; many intersecting slickensides; slightly alkaline (pH 7.5); gradual wavy boundary. (10 to 22 inches thick)
Bk--36 to 60 inches; dark grayish brown (2.5Y 4/2) clay, very dark grayish brown (2.5Y 3/2) moist; massive; hard, firm, sticky and plastic; many very fine interstitial and common very fine tubular pores; carbonates disseminated and segregated as many fine soft masses and seams; 3 to 5 percent pebbles of sandstone, basalt, and serpentine; moderately alkaline (pH 8.0).
TYPE LOCATION: Santa Clara County, California; east of Morgan Hill; .2 mile south of Tenant Road on Foothill Road and 0.1 mile east.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches is 59 degrees to 64 degrees F. The soils usually are dry all the time from the end of May until November and unless irrigated have cracks 1/2 to 2 inches wide that extend from the surface to a depth of 25 inches or more. The soils are moist the rest of the year and the cracks remain closed during the moist period. There are common to many slickensides from a depth of about 10 inches to about 40 inches or more. Slopes are simple and are 0 to 15 percent.
The A horizon (or the soils from the surface to a depth of about 20 to 39 inches) is dark gray, very dark gray or black in 10YR, 2/5Y, 5Y, or neutral hue. It is heavy clay loam, silty clay or clay and is slightly acid to moderately alkaline, but is not calcareous. Some pedons have A/B horizons in which there is evidence of mixing and A horizon and B horizon soil material with small to large lumps of the two respective horizons.
The B horizon is grayish brown to yellowish brown or light olive brown (10YR 3/1, 4/1, 5/2, 4/2, 5/3, 6/3, 6/4; 2.5Y 4/2, 5/2, 5/4, 6/2, 6/3, 6/4; 5Y 5/2, 6/2). It is clay loam, silty clay loam, or clay, but some pedons have strata of loam or fine sandy loam below a depth of 40 inches. In most pedons, some or most of the carbonates are in fine segregations. Some pedons do not have pebbles of sandstone, basalt and serpentine in the Bk horizon.
COMPETING SERIES: These are the Aido, Alo, Altamont, Auld, Bosanko, Cibo, Diablo, Myers, Porterville, Sehorn and Vaquero series. Aido, Alo, Auld, Bosanko and Vaquero soils have a paralithic contact within a depth of 40 inches. Altamont soils have a paralithic contact within a depth of 60 inches. Cibo and Sehorn soils have a lithic contact within a depth of 40 inches. Diablo soils are on undulating complex slopes of mostly more than 9 percent, are well drained and have a paralithic contact at depths of 40 to 80 inches. Myers soils lack segregated lime in the subsoil and have moist color values of 4 only in the A horizon. Porterville soils have 5YR and 7.5YR dominantly throughout.
GEOGRAPHIC SETTING: Cropley soils are on smooth slopes of less than 9 percent at elevations of 30 to 2100 feet. They formed in deep alluvium, mostly of fine texture from soils weathered from shale, on fans and floodplains. The climate is dry subhumid mesothermal. Summers are warm and dry and winters are cool and moist. Mean annual precipitation is 12 to 30 inches. Average January temperature is about 49 degrees F. in most areas, but is about 56 degrees when close to the coast of California; average July temperature is about 68 degrees F.; mean annual temperature is about 57 degrees to 62 degrees F. The freeze-free season ranges from 200 to 330 days and up to 360 days along the coast.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Alo, Altamont and Diablo soils and the Antioch, Salinas, and Sorrento soils. Antioch soils have a natric horizon. Salinas and Sorrento soils have less than 35 percent clay and do not crack when dry.
DRAINAGE AND PERMEABILITY: Moderately well and well drained; medium to very high runoff; slow permeability.
USE AND VEGETATION: Used for growing row, irrigated, truck, and forage crops, apricots, prunes, and dry pasture. Uncultivated areas have annual grasses and forbs with some scattered live oak trees.
DISTRIBUTION AND EXTENT: Fans and floodplains of the Coast Range in California. The soils are of moderate extent.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Santa Clara County (Santa Clara Area), California, 1941.
REMARKS: The series now includes some of the former Raynor soils more than 40 inches deep that were mapped on gentle smooth slopes.
Series reclassified on September, 1994. Horizon designations and competing soils updated June 2001.
Slope range expanded to 15 percent to accomodate observations in Santa Monica Mountains October 2001.
Because a search of the database revealed that both well and moderately well drained components were being used, well drained was added to the OSD to accomodate those components on floodplains, October 2004.