LOCATION OXFORD IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Vertic Haploxerepts
TYPICAL PEDON: Oxford silty clay loam--cropland. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 5 inches; reddish brown (5YR 5/3) silty clay, reddish brown (5YR 4/3) moist; weak fine subangular blocky structure parting to moderate fine granular; soft, friable, moderately sticky and moderately plastic; few fine and very fine roots; slightly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (3 to 6 inches thick)
AB--5 to 11 inches; reddish brown (5YR 5/3) silty clay, reddish brown (5YR 4/3) moist; weak medium subangular blocky structure parting to moderate medium granular; hard, firm, very sticky and very plastic; few fine and very fine roots; few 0.25 to 0.5 inch wide vertical cracks filled with surface material; slightly effervescent; slightly alkaline (pH 7.8); clear wavy boundary. (0 to 6 inches thick)
Bw1--11 to 16 inches; light reddish brown (5YR 6/3) silty clay, reddish brown (5YR 4/4) moist; strong fine subangular blocky structure; very hard, very firm, very sticky and very plastic; few fine and very fine roots; common 0.25 to 0.5 inch wide vertical cracks filled with surface material; slightly effervescent; moderately alkaline (pH7.9); clear smooth boundary.
Bw2--16 to 26 inches; light reddish brown (5YR 6/3) silty clay, reddish brown (5YR 4/4) moist; strong fine subangular blocky structure parting to moderate fine angular blocky; extremely hard, very firm, very sticky and very plastic; few fine roots; common 0.25 to 1 inch wide vertical cracks filled with surface material; slightly effervescent; moderately alkaline (pH 8.1); clear smooth boundary. (Combined thickness of the Bw horizons is 12 to 33 inches)
Bky1--26 to 38 inches; light reddish brown (5YR 6/3) clay, reddish brown (5YR 4/4) moist; moderate medium and fine angular blocky structure; extremely hard, very firm, very sticky and very plastic; few fine distinct red (2.5YR 4/6) irregularly shaped masses of iron accumulation that are relict redoximorphic features; common 0.25 to 1.12 inches wide vertical cracks filled with surface material; large pressure faces with very dark gray (5YR 3/1) organic stains; strongly effervescent; 4 percent gypsum; moderately alkaline (pH 8.4); clear wavy boundary. (7 to 24 inches thick)
Bky2--38 to 47 inches; light reddish brown (5YR 6/3) clay, reddish brown (5YR 4/4) moist; strong medium angular blocky structure; extremely hard, very firm, very sticky and very plastic; few fine prominent red (2.5YR 4/6) irregularly shaped masses of iron accumulation that are relict redoximorphic features; common 0.25 to 1.12 inches wide vertical cracks extending to 44 inches filled with surface material; cracks and pressure faces with black (5YR 2/1) and very dark gray (5YR 3/1) organic stains; strongly effervescent; 6 percent gypsum; moderately alkaline (pH 8.2); clear wavy boundary. (5 to 11 inches thick)
By--47 to 63 inches; pinkish gray (5YR 7/2) silty clay, reddish brown (5YR 5/3) moist; massive; extremely hard, very firm, very sticky and very plastic; common medium distinct dark reddish brown (2.5YR 3/4) irregularly shaped masses of iron accumulation that are relict redoximorphic features; few very dark gray (5YR 3/1) organic stains along pressure faces; common fine gypsum crystals in veins; 3 percent gypsum; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Franklin County, Idaho; about 2.5 miles southeast of Banida; approximately 2,400 feet east and 600 feet south of the northwest corner of section 18, T. 14 S., R. 39 E.
RANGE IN CHARACTERISTICS:
Soil moisture - Usually dry in the moisture control section for 45 to 60 consecutive days in the 4 months following the summer solstice.
Mean annual soil temperature - 44 to 47 degrees F.
Vertic features - Cracks: Extend to the base of the surface horizon annually and are open to the soil surface in some years.
Linear extensibility (LE) - 6 to 9 cm.
Particle-size control section - Clay content: 40 to 58 percent.
A horizons
Hue: 7.5YR or 5YR.
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 or 4, dry or moist.
Gypsum content: 1 to 5 percent.
Bw horizon
Value: 5 or 6 dry, 4 or 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Silty clay or clay.
Reaction: Slightly alkaline or moderately alkaline.
Gypsum content: 1 to 5 percent.
Bky horizon
Value: 5 through 7 dry, 3 through 5 moist.
Chroma: 3 through 6, dry or moist.
Texture: Silty clay or clay.
Reaction: Slightly alkaline or moderately alkaline.
Effervescence: Slight or strong.
Calcium carbonate equivalent: 5 to 15 percent.
Gypsum content: 1 to 20 percent.
By horizon
Value: 6 or 7 dry, 4 or 5 moist.
Texture: Silty clay or clay.
Calcium carbonate equivalent: 5 to 15 percent
Gypsum content: 1 to 5 percent.
COMPETING SERIES: These are the Banida, Magic, and Market series.
Banida soils are not effervescent throughout and do not have redox concentrations in the lower part of the particle-size control section. Magic soils are moderately deep to lithic contacts. Market soils have hue of 10YR through 5Y.
GEOGRAPHIC SETTING: Oxford soils are on dissected lake terraces. These soils formed in lacustrine deposits and alluvium derived from mixed sources. Slopes are 2 to 50 percent. Elevations range from 4,700 to 5,200 feet. The mean annual precipitation is 15 to 18 inches with most of the precipitation coming in the winter months as snow. The mean annual air temperature is 42 to 45 degrees F. and the mean summer air temperature is 61 to 66 degrees F. The frost-free period is 90 to 105 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Ant Flat, Banida, Manila, and Yago soils. Ant Flat soils have a mollic epipedon. Banida soils have more than 0.7 percent organic carbon in the surface horizon. Yago soils are clayey-skeletal. Manila soils have a mollic epipedon, an argillic horizon and hues of 7.5YR or yellower throughout the profile. Ant Flat soils are along drainageways. Banida soils are in concave areas and on north and east-facing slopes. Manila and Yago soils are on fan remnants and foothills.
DRAINAGE AND PERMEABILITY: Moderately well drained; medium to very high surface runoff; very slow permeability (low or moderately low saturated hydraulic conductivity).
USE AND VEGETATION: Oxford soils are used dominantly for dryland cropping. Natural vegetation is assumed to have been basin big sagebrush, bluebunch wheatgrass, and sod-forming grasses.
DISTRIBUTION AND EXTENT: Southeastern Idaho. These soils are moderately extensive. The series concept and main acreage is in MLRA 28A, while other acreage occurs in MLRA 13.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Phoenix, Arizona.
SERIES ESTABLISHED: Portneuf Area, Idaho, 1918.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the soil surface to 11 inches (Ap and AB horizons).
Cambic horizon - The zone from 11 to 26 inches (Bw1 and Bw2 horizons).
Vertic subgroup feature - The zone from the soil surface to 40 inches with linear extensibility of 6.0 cm or more; additional support for the concept is based on the cracks described in the horizons above 47 inches.
Particle-size control section - The zone from 10 to 40 inches (Bw1, Bw2, and Bky1 horizons, and parts of the AB and Bky2 horizons).
ADDITIONAL DATA: NSSL sample #S79ID-041-002.