LOCATION DINGMAN CAEstablished Series
TAXONOMIC CLASS: Fine, magnesic, mesic Pachic Ultic Argixerolls
TYPICAL PEDON: Dingman cobbly clay loam - on a north facing concave slope of 30 percent under chaparral and mixed cypress pine woodland at 1,760 feet elevation. (Colors are for dry soil unless otherwise stated. When described on September 11, 1979, the soil was dry throughout.)
A--0 to 5 inches; dark reddish gray (5YR 4/2) cobbly clay loam, dark reddish brown (5YR 3/2) moist; weak coarse and very coarse granular structure; slightly hard, friable, sticky and plastic; few very fine and fine roots; common very fine and fine tubular pores; 15 percent 2 to 75 mm pebbles and 15 percent 75 to 150 mm cobbles; mildly alkaline (pH 7.5); clear smooth boundary. (4 to 8 inches thick)
Bt1--5 to 14 inches; dark reddish gray (5YR 4/2) cobbly clay loam, dark reddish brown (5YR 3/2) moist; moderate coarse subangular blocky structure; hard, firm, sticky and plastic; common very fine and fine and many medium and coarse roots; common very fine and fine tubular pores; few thin clay films on peds and in pores; 15 percent 2 to 75 mm pebbles and 15 percent 75 to 150 mm cobbles; mildly alkaline (pH 7.5); gradual smooth boundary. (8 to 15 inches thick)
Bt2--14 to 26 inches; dark reddish brown (5YR 3/2) gravelly clay, dark reddish brown (5YR 3/3) moist; strong medium prismatic structure; very hard, very firm, very sticky and very plastic; common very fine and fine and many medium roots; many very fine and fine tubular pores; many thick clay films on peds and in pores; 35 percent 2 to 75 mm pebbles; mildly alkaline (pH 7.6); clear smooth boundary. (8 to 17 inches thick)
Crt--26 to 35 inches; variegated dark brown and dark yellowish brown (10YR 4/3, 4/4) weathered serpentine and peridotite, very dark grayish brown and light yellowish brown (10YR 3/2, 6/4) moist, roots extending along cracks down into weathered material; common thick clay films on rock fragments.
TYPE LOCATION: Mendocino County, California; about 5.5 air miles south of Covelo, 1.1 miles along the "My Ranch" road, from the main gate at Inspiration Point, then 0.4 miles along dirt road toward Round Mountain, on north facing roadcut, 900 feet west and 700 feet north of the southest corner of sec. 31, T. 22 N., R. 12 W., MDBM, Jamison Ridge Quadrangle.
RANGE IN CHARACTERISTICS: Thickness of the solum and depth to a paralithic contact is 20 to 40 inches. The soil between the depths of 7 and 21 inches is dry in all parts from June to October and is moist in all parts from December to May. The mean annual soil temperature ranges from 54 degrees to 58 degrees F. Organic matter to a depth of 20 inches or more is greater than 1 percent. Base saturation ranges from 50 to 100 percent throughout and is below 75 percent in some part of the upper 30 inches. The calcium to magnesium ratio is 1:1 or less. The soil is neutral or mildly alkaline throughout.
The A horizon is 10YR 4/2; 7.5YR 4/2, or 5YR 4/2. Moist colors are 7.5YR 3/2 or 5YR 3/2. It has 27 to 35 percent clay, 10 to 20 percent cobbles and 10 to 20 percent gravel.
The Bt horizon is 7.5YR 4/2; 5YR 3/2 or 4/2. Moist colors are 10YR 3/3; 7.5YR 3/2; 5YR 3/2, or 3/3. It is clay loam or clay with 35 to 55 percent clay, 0 to 20 percent cobbles and 10 to 35 percent gravel. It averages 35 to 50 percent clay and 20 to 35 percent rock fragments.
COMPETING SERIES: These are the Beaughton, Dubakella and Henneke series in other families. Dubakella soils are clayey-skeletal and lack a mollic epipedon. Beaughton and Henneke soils are 10 to 20 inches deep to a lithic contact and are clayey-skeletal.
GEOGRAPHIC SETTING: The Dingman soils are on hills and mountains and have slopes of 5 to 50 percent. The soils formed in material weathered from serpentine and peridotite. Elevations are 1,500 to 3,800 feet. The climate is subhumid with hot dry summers and cool moist winters. Mean annual precipitation varies from 40 to 55 inches. Mean January temperature is 40 degrees F; mean July temperature is 70 degrees F; mean annual temperature varies from 52 degrees to 57 degrees F. Frost-free season ranges form 125 to 200 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Beaughton soils. They occur on convex slopes and near rock outcrops.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; slow permeability.
USE AND VEGETATION: Used for watershed and habitat for wildlife. Vegetation is cypress, coffee berry, canyon live oak, manzanita, chamise, poison oak, Jeffrey pine, digger pine, and madrone.
DISTRIBUTION AND EXTENT: Northern California in the Coast Range. The soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: Mendocino County, California, Eastern Mendocino SSA 1985.
REMARKS: The Dingman series was formerly called Zenia, and Enzia. Name was changed to avoid confusion with other series. This pedon, samples 80CA-145-27 (2 and 3), had serpentinitic mineralogy according to the National Soil Survey Laboratory, Lincoln, Nebraska.