LOCATION CROPLEY CAEstablished Series
The Cropley series consists of very deep, moderately well and well drained soils that formed in alluvium from mixed rock sources. Cropley soils are on alluvial fans, floodplains and in small basins. Slopes range from 0 to 15 percent. The mean annual precipitation is about 16 inches and the mean annual temperature is about 60 degrees F.
TAXONOMIC CLASS: Fine, smectitic, thermic Aridic Haploxererts
TYPICAL PEDON: Cropley clay, 0 to 2 percent slopes, on a west facing 1 percent slope under a cover of annual grasses and forbs, at an elevation of 541 feet. When described on November 8, 2007, the soil was moist to 11 inches and dry below. (Colors are for dry soil unless otherwise noted).
A1--0 to 4 inches; very dark gray (10YR 3/1) broken face clay, black (10YR 2/1) broken face moist; 45 percent clay; strong coarse subangular blocky structure; hard, firm, very sticky, very plastic; common very fine roots; many very fine tubular pores; slightly acid, pH 6.2 by pH meter 1:1 water; clear smooth boundary.
A2--4 to 11 inches; very dark gray (10YR 3/1) broken face clay, black (10YR 2/1) broken face moist; 50 percent clay; strong coarse subangular blocky structure; hard, firm, very sticky, very plastic; common very fine roots; common very fine tubular pores; neutral, pH 6.9 by pH meter 1:1 water; clear smooth boundary. (combined A horizons 5 to 15 inches thick)
Bss1--11 to 24 inches; dark gray (2.5Y 4/1) broken face clay, black (2.5Y 2.5/1) broken face moist; 50 percent clay; strong coarse subangular blocky structure; hard, firm, very sticky, very plastic; common very fine roots; common very fine tubular pores; 20 percent pressure faces on slickensides and 70 percent clay films on all faces of peds; slightly alkaline, pH 7.6 by pH meter 1:1 water; gradual smooth boundary.
Bss2--24 to 33 inches; dark gray (2.5Y 4/1) broken face clay, black (2.5Y 2.5/1) broken face moist; 50 percent clay; strong coarse subangular blocky structure; hard, firm, very sticky, very plastic; common very fine roots; common very fine tubular pores; 30 percent pressure faces on slickensides; slightly alkaline, pH 7.8 by pH meter 1:1 water; gradual smooth boundary.
Bss3--33 to 51 inches; dark gray (2.5Y 4/1) broken face clay, very dark gray (2.5Y 3/1) broken face moist; 50 percent clay; strong coarse subangular blocky structure; hard, firm, very sticky, very plastic; few very fine roots; few very fine tubular pores; 40 percent pressure faces on slickensides; 10 percent irregular carbonate masses in matrix; very slight effervescence; slightly alkaline, pH 7.8 by pH meter 1:1 water; abrupt smooth boundary. ( combined Bss horizons 14 to 38 inches thick)
BCk1--51 to 57 inches; brown (7.5YR 5/3) broken face sandy clay loam, brown (7.5YR 4/3) broken face moist; 32 percent clay; moderate medium subangular blocky structure; hard, firm, moderately sticky, moderately plastic; many very fine tubular pores; 10 percent clay films on all faces of peds; 10 percent irregular carbonate masses in matrix; strong effervescence; moderately alkaline, pH 8.0 by pH meter 1:1 water; clear smooth boundary.
BCk2--57 to 63 inches; brown (7.5YR 5/3) broken face sandy clay loam, brown (7.5YR 4/3) broken face moist; 28 percent clay; moderate medium subangular blocky structure; slightly hard, friable, moderately sticky, slightly plastic; common very fine tubular pores; 10 percent clay films on all faces of peds; 1 percent subangular indurated 2 to 75 millimeter mixed rock fragments; strong effervescence; moderately alkaline, pH 8.0 by pH meter 1:1 water;
TYPE LOCATION: Santa Clara County, California, Ed Levin County Park, City of Milpitas, west of Sandy Wool lake, west of main road in field, west of curve in road to middle of field., in an unsectionized area of Township 5S, Range 1E, 4146038 UTM Northing, 600126 UTM Easting, Zone 10, NAD83 - U.S.G.S Quad: Calaveras Reservoir, California.
RANGE IN CHARACTERISTICS: Depth to segregated carbonate masses is 32 to 51 inches in most pedons, however some areas lack carbonates. The mean annual soil temperature at a depth of 20 inches is 59 to 64 degrees F. The particle size control section averages 40 to 60 percent clay, and 0 to 10 percent rock fragments, mostly gravel in size. Mineralogy is smectitic. Organic matter ranges from 1 to 3 percent to a depth of 10 inches. The soils usually are dry in the soil moisture control zone from May 1 to October 31, 180 days, and moist the rest of the year. Reversible surface- initiated cracks to 2 inches wide extend to a depth of 25 inches or more when the soil is not irrigated. Slickensides range from common to many in the Bss horizon from about 10 to 40 inches or more. Slopes are simple and are 0 to 15 percent.
The A horizons dry color is 10YR 4/2, 4/1, 3/2, 3/1, 2/1 or 5Y 3/1. Moist color is 10YR 3/2, 3/1, 2/2, 2/1 or N 2/. Texture is heavy clay loam, silty clay loam, silty clay or clay. Clay content ranges from 40 to 60 percent. Rock fragments range from 0 to 10 percent gravel. Reaction ranges from 5.6 to 8.4 and the horizon is non-calcareous. Some pedons have A/B horizons in which there is evidence of mixing of the A horizon and the Bss horizon soil material with small to large clumps of mixed soil material.
The Bss horizons dry color is 10YR 6/3, 6/2, 5/4, 5/3, 5/2, 4/3, 4/2, 4/1, 3/2, 3/1; 5Y 6/2, 3/1; 2.5Y 6/2, 5/2 or 4/1. Moist color is 10YR 4/4, 4/3, 4/2, 4/1, 3/3, 3/2, 3/1, 2/1; 5Y 4/2, 3/1; 2.5Y 4/2, 3/2, 3/1 or 2.5/1. Texture is clay loam, silty clay loam, silty clay or clay. Clay content ranges from 40 to 60 percent. Rock fragments range from 0 to 10 percent gravel. Reaction ranges from 6.1 to 8.4.
The BCk or Ck horizons dry color is 10YR 7/4, 7/2, 6/4, 6/3, 5/4, 5/3, 5/2, 4/4, 4/3, 4/2; 7.5YR 5/3, 4/2; 5Y 6/3, 5/2; 2.5Y 6/2, 5/3, 5/2, 4/3 or 4/2. Moist color is 10YR 6/4, 5/4, 5/3, 4/4, 4/3, 4/2, 3/4, 3/3, 3/2; 7.5YR 4/3, 4/2; 5Y 4/4, 4/2; 2.5Y 5/4, 4/4, 4/3, 4/2, 3/3 or 3/2. Texture is sandy clay loam, clay loam or clay. Some pedons have strata of loam or fine sandy loam below the depth of 40 inches. Clay content ranges from 27 to 60 percent. Rock fragments range from 0 to 10 percent gravel. Reaction ranges from 6.1 to 8.4.
COMPETING SERIES: These are the Aido, Alo, Altamont, Auld, Bonsanko, Cibo, Diablo, Myers, Porterville, Sehorn and Vaquero series. Aido, Alo, Auld, Bonsanko 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 have a paralithic contact at depths of 40 to 80 inches and have chromas of 1.5 or less in the A horizon. Myers soils lack segregated carbonates in the subsoil, have moist color values of 4, 5 or 6 in the A horizon, and are located in MLRA 17 with greater than 30 degrees F. between mean summer and mean winter temperatures. Porterville soils dominantly have hues of 5YR and 7.5YR and are located in MLRA 17 with greater than 30 degrees F. between mean summer and mean winter temperatures.
GEOGRAPHIC SETTING: Cropley soils are on alluvial fans, floodplains and in small basins. Slopes are smooth and are 0 to 15 percent. Cropley soils formed in fine textured alluvium weathered from shale, sandstone and mudstone. Elevation is 10 to 2100 feet. The climate is dry subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 12 to 30 inches. The mean annual temperature is 57 to 62 degrees F. Average January temperature is about 49 degrees F. in most areas, but is about 56 degrees F. close to the coast of California; average July temperatures is about 68 degrees f. Frost free season is 200 to 330 days and up to 360 days along the coast.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Alo, Altamont, Diablo soils, and the Antioch, Salinas and Sorrento soils. Antioch soils have a natric horizon, Salinas soils 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. The soils are not flooded, flooding may be controlled in some areas.
USE AND VEGETATION: This soil is used for irrigated row and truck crops, irrigated and dry pasture, apricots, prunes and for urban development. Vegetation in uncultivated or undeveloped areas is annual grasses and forbs with some scattered live oak.
DISTRIBUTION AND EXTENT: The soils are moderately extensive and are mapped in MLRA?s 14 and 19.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: MO2 Davis, California
SERIES ESTABLISHED: Santa Clara County, California, Santa Clara Area, 1941.
REMARKS:
Official Cropley type location moved from existing site to new site near Milpitas, California, November, 2007 during soil survey of the Santa Clara area. Entire series description revised at that time. The Cropley series now includes some of the former Raynor soils more than 40 inches deep that were mapped on gentle smooth slopes.
Cropley series reclassified on September, 1994. Horizon designations and competing soils updated June 2001. Slope range expanded to 15 percent to accommodate observations in the Santa Monica Mountains October, 2001. Database search revealed well and moderately well drained components so well drained was added to the OSD for those components on floodplains, October 2004. Cropley soils mapped in Santa Cruz county near the Pacific Ocean do not open cracks until July and would not meet the criteria of 180 days dry for the Aridic subgroup.
ADDITIONAL DATA: NASIS SITE ID: 07ca085641468, NSSL Lab Data 69CA071026