LOCATION CUSHENBURY CAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Haploxerolls
TYPICAL PEDON: Cushenbury sandy loam, on a 15 percent south facing slope under a pinyon pine, chamise, flattop buckwheat and perennial grasses at 4,800 feet. (Colors are for dry soil unless otherwise stated. When described the soil was dry throughout.)
A11--0 to 14 inches; brown (10YR 5/3) loamy sand, dark brown (10YR 3/3) moist; moderate very fine subangular blocky structure; slightly hard, very friable; few very fine roots; common very fine interstitial pores; 10 percent pebbles (1/4 to 3/8 inch); neutral (pH 6.7); gradual smooth boundary. (7 to 14 inches thick)
A12--14 to 27 inches; brown (10YR 5/3) sandy loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few very fine, few fine roots; common very fine interstitial pores; 10 percent pebbles (1/4 to 3/8 inch); slightly acid (pH 6.5); gradual smooth boundary. (6 to 14 inches thick)
B2t--27 to 39 inches; yellowish brown (10YR 5/4) gravelly sandy loam, dark yellowish brown (10YR 4/4) moist; strong medium subangular blocky structure; hard, friable, slightly sticky and nonplastic; few very fine, few fine roots; common very fine interstitial, few very fine tubular pores; few thin clay films in bridges between mineral grains; 20 percent pebbles; slightly acid (pH 6.4); gradual smooth boundary. (7 to 12 inches thick)
Cr--39 inches; weathered granitic rock that can be cut with hand tools.
TYPE LOCATION: San Bernardino County, California; on Oak Springs Ranch Road, about 0.5 miles north of Oak Springs Ranch; NW1/4 NW1/4 SE1/4 section 5, T.3N., R.2W.
RANGE IN CHARACTERISTICS: Depth to paralithic contact with weathered granitic rock ranges from 20 to 40 inches. The mean annual soil temperature is 53 to 59 degrees F. Soil between depths of 8 and 24 inches usually is moist in some part from late November to late April or early May, and is continuously dry the rest of the time. The control section contains more than 50 percent fine or coarser sand in the fine earth fraction. The soil has 5 to 25 percent gravel by volume.
The A horizon is brown or grayish brown (10YR 5/2, 5/3, 4/3). It is typically loamy sand but ranges from gravelly loamy sand, sandy loam to gravelly sandy loam and averages 4 to 8 percent clay. It is neutral in the upper part but ranges to slightly acid in the lower part. The base saturation ranges from 75 to 90 percent. Organic matter decreases to less than 1 percent at a depth of about 14 inches in the A horizon.
The B2t horizon is yellowish brown, brown, or strong brown (10YR 5/4, 5/3,; 7.5YR 5/6, 5/8). It is gravelly sandy loam, or sandy loam averages 4 to 10 percent clay and has an increase of only 1 to 2 percent. It is slightly acid or neutral. This horizon has moderate to strong, medium to coarse, angular or subangular blocky structure.
Some pedons have a C horizon that is brown or yellowish brown (10YR 5/3, 5/4). It is gravelly sandy loam or sandy loam and is slightly acid or neutral.
COMPETING SERIES: These are the Anders, Chenoweth, Cleverly, Conconully, Donavan, Duart, Hesslan, Juliaetta, Knutsen, Laidlaw, Newbon, Owhi, Phoebe and Wato series. Chenoweth, Cleverly, Conconully, Donavan, Juliaetta, Knutsen, Newbon, Owhi, Phoebe and Wato soils lack a paralithic contact within a depth of 40 inches. Anders, Duart and Hesslan soils have less than 50 percent total sand in the control section and have silica cemented layer at a depth of 20 to 40 inches.
GEOGRAPHIC SETTING: Cushenbury soils are on hilly uplands and have gradients of 15 to 30 percent. They formed in residuum from grandiorite, granite, and other granitic rocks. Rock out crop commonly occurs with soil. Elevations are 4,500 to 5,500 feet. The climate is subhumid mesothermal having cool, moist winters and warm, dry summers. Th mean annual precipitation is 14 to 18 inches of which 1/4 to 1/2 falls as snow. The average January temperature is 40 to 43 degrees F.; the average July temperature is 66 to 70 degrees F.; and the mean annual temperature is 53 degrees F. The frost free season is 150 to 175 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arrastre, Crafton and Tollhouse soils. Arrastre soils lack a mollic epipedon,and are 20 to 40 inches deep to a lithic contact. Crafton soils lack a cambic horizon. Tollhouse soils have a paralithic contact at a depth of less than 20 inches.
DRAINAGE AND PERMEABILITY: Well drained; medium runoff; moderately rapid permeability.
USE AND VEGETATION: Dryland pasture, wildlife habitat. Natural vegetation is pinyon pine, chamise, annual grasses and forbs, some perennial grasses.
DISTRIBUTION AND EXTENT: Foothills of the San Bernardino Mountains near Bowen Ranch and Oak Springs along Arrastre Canyon. The soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Davis, California
SERIES ESTABLISHED: San Bernardino County, California, Mojave River Area, 1978.
REMARKS: The activity class was added to the classification in February of 2003. Competing series were not checked at that time. - ET