LOCATION MCCOY CAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, thermic Pachic Argixerolls
TYPICAL PEDON: McCoy clay loam, annual range. (Colors are for dry soil unless otherwise noted)
Ap--0 to 2 inches; dark brown (10YR 3/3) loam, very dark grayish brown (10YR 3/2) moist; compound moderate medium platy and moderate subangular blocky structure, platy structure due to cattle trampling; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine interstitial and few very fine tubular pores; about 7 percent fine angular pebbles and mineral grains; slightly acid (pH 6.5); abrupt smooth boundary. (0 to 10 inches thick)
A12--2 to 4 inches; dark brown (10YR 3/3) dry and moist) clay loam; moderate medium angular blocky structure; hard, friable, sticky and plastic; common fine and few very fine roots; common very fine and few very fine tubular pores; about 10 percent fine angular pebbles and mineral grains; neutral (pH 7.0); clear wavy boundary. (2 to 24 inches thick)
A13--4 to 18 inches; dark brown (10YR 3/3) clay loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; common fine and few very fine roots; common very fine interstitial, many fine and common very fine tubular pores; about 10 percent fine angular pebbles and mineral grains; neutral (pH 7.0); clear wavy boundary. (4 to 16 inches thick)
B2t--18 to 22 inches; dark brown (10YR 3/3) clay loam, very dark grayish brown (10YR 3/2) moist; weak medium subangular blocky structure; hard, friable, sticky and plastic; common fine, few very fine roots; few very fine interstitial and few very fine tubular pores; many thin clay films lining pores, on faces of peds and as bridges; about 13 percent fine angular pebbles and mineral grains; few moderately thick films lining pores; slightly alkaline (pH 7.5); abrupt wavy boundary. (4 to 24 inches thick)
B3t--22 to 27 inches; dark yellowish brown (10YR 4/4) clay loam, dark brown (10YR 3/3) moist; massive; hard, friable, slightly sticky and plastic; few very fine roots; few very fine interstitial, few fine and very fine tubular pores; common thin clay films as bridges and lining pores; about 15 percent fine angular pebbles and mineral grains; slightly alkaline (pH 7.5); abrupt boundary. (0 to 12 inches thick)
Cr--27 to 37 inches; clean weathered granodiorite; noncalcareous; slightly alkaline (pH 7.8).
TYPE LOCATION: Monterey County, California; about 8 miles northeast of Gonzales in Johnson Canyon; center of SE 1/4, NW 1/4 Sec. 31, T.15S., R.6E.
RANGE IN CHARACTERISTICS: Depth to a paralithic contact of weathered crystalline rock is 25 to 40 inches. The soil between a depth of about 4 and 12 inches becomes moist in some part in November or early December and remains moist until May. The mean annual soil temperature is 59 degrees to 65 degrees F. Organic matter content is 1 to 4 percent in the upper 20 inches and decreases regularly to less than 1 percent 25 to 30 inches below the surface. Rock fragments, mostly fine gravel, make up 1 to 15 percent of the solum.
The A1 horizon is very dark gray, dark gray, very dark grayish brown, dark grayish brown or dark brown (10YR 3/1, 4/1, 3/2, 4/2, 3/3) and dark brown or brown (7.5YR 3/2, 4/2). It is loam, clay loam or sandy clay loam. This horizon is slightly acid to slightly alkaline.
The B2t horizon is very dark grayish brown, dark grayish brown, dark brown (10YR 3/2, 4/2, 3/3) dark brown or brown (7.5YR 3/2, 4/2) and dark reddish brown or dark reddish gray (5YR 3/2, 4/2). It is clay loam or sandy clay loam with an absolute clay increase of 5 to 9 percent over the A1 horizon. Reaction is mildly alkaline or moderately alkaline. Most pedons have a B3 horizon overlying the weathered crystalline bedrock.
COMPETING SERIES: These are the Arujo (T), Botella, Elkhorn, Havala (T), and Lockwood series. Arujo soils have a paralithic contact of bedrock at depths of 40 to 60 inches below the soil surface. Botella, Elkhorn, Havala and Lockwood soils are all formed on alluvial materials and lack a paralithic contact.
GEOGRAPHIC SETTING: The McCoy soils are on hilly uplands. They formed in residuum weathered from granodiorite, granite, and schist. The rocks are deeply weathered. Elevations are 400 to 2,900 feet. The climate is subhumid mesothermal with warm dry summers and cool moist winters. Mean annual precipitation is 12 to 20 inches. Average January temperature is about 49 degrees F., average July temperature is about 64 degrees F., and mean annual temperature is 57 degrees to 59 degrees F. The freeze-free season is about 250 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cieneba, Danville, Gloria, Linne, Placentia, San Timoteo, Sheridan and Vista series. Cieneba soils are 4 to 20 inches deep to a paralithic contact and lack Mollic epipedons. Danville soils lack a paralithic contact and have more than 35 percent clay in the B2t horizon. Gloria soils lack a paralithic contact, have less than 1 percent organic carbon in the A horizon and have more than 35 percent clay in the B2t horizon. Linne soils are calcareous throughout and lack a B2t horizon. Placentia soils have hard and massive A horizons and more than 35 percent clay and more than 15 percent exchangeable sodium in the B2t horizon. San Timoteo soils have light colored A horizons; less than 18 percent clay, lack a B2t horizon and are calcareous throughout. Sheridan soils have less than 18 percent clay throughout and lack a B2t horizon. Vista soils have less than 1 percent organic matter in the A1 horizon and lack a B2t horizon.
DRAINAGE AND PERMEABILITY: Well drained; medium to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: Used mostly for range. A few areas have been cultivated to small grain. Naturalized and native vegetation consists of annual grasses and forbs and some brush and oak trees.
DISTRIBUTION AND EXTENT: Central part of the Coast Range in California. The soils are of moderate extent.
MLRA OFFICE RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Monterey County, California, 1972.
REMARKS: 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 1/76.