LOCATION BLACKFOOT IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Fluvaquentic Haploxerolls
TYPICAL PEDON: Blackfoot loam, pasture. Colors are for dry soil unless otherwise noted.
Ap--0 to 8 inches; gray (2.5Y 5/1) loam, very dark grayish brown (2.5Y 3/2) moist; weak thin and medium platy structure parting to moderate medium granular; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine pores; few worm channels and casts; strongly effervescent; slightly alkaline (pH 7.7); clear smooth boundary. (6 to 12 inches thick)
Bw--8 to 18 inches; gray (2.5Y 5/1) (light brownish gray 10YR 6/2 crushed) loam, very dark grayish brown (10YR 3/2) moist; weak medium and coarse granular structure parting to weak fine and medium subangular blocky; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine and few medium tubular pores; few worm channels and casts; strongly effervescent; slightly alkaline (pH 7.7); clear smooth boundary. (7 to 14 inches thick)
Bkg--18 to 21 inches; gray (2.5Y 5/1) (light brownish gray 10YR 6/2 crushed) silty clay loam, very dark grayish brown (2.5Y 3/2) (very dark gray 2.5Y 3/1 crushed) moist; common fine faint masses of iron accumulation; brown (10YR 5/3) dry; weak thin platy structure parting to weak fine and medium granular; hard, very friable, moderately sticky and moderately plastic; common very fine and fine roots; many very fine and fine tubular pores; common worm channels and casts, strongly effervescent, very few fine white spots; slightly alkaline (pH 7.7); clear smooth boundary. (0 to 6 inches thick)
Bg--21 to 25 inches; gray (2.5Y 6/1) silty clay loam, dark grayish brown (10YR 4/2) moist; common fine faint masses of iron accumulartion; brown (10YR 5/3) dry; weak coarse and medium granular structure; hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; many very fine and fine tubular pores; few worm channels and casts; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 8 inches thick)
B'kg--25 to 29 inches; light gray (2.5Y 6/1) loam, dark grayish brown (2.5Y 4/2) moist; common medium distinct masses of iron accumulation; brown (10YR 5/3), dark brown (10YR 3/3) moist; few medium distinct masses or iron depletion; dark grayish brown (10YR 4/2), very dark gray (10YR 3/1) moist; weak thin and medium platy structure parting to weak fine and medium granular; hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and few fine and medium tubular pores; few worm channels and casts; strongly effervescent, very few fine veins and spots of calcium carbonate; moderately alkaline (pH 7.9); clear wavy boundary. (0 to 6 inches thick)
B'g1--29 to 40 inches; light gray (2.5Y 6/1) fine sandy loam, dark grayish brown (2.5Y 4/2) moist; few fine distinct masses of iron depletion, dark grayish brown (10YR 4/2) very dark gray (10YR 3/1) moist; massive; hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and few fine medium tubular pores; slightly effervescent; moderately alkaline (pH 7.9); clear wavy boundary. (0 to 15 inches thick)
B'g2--40 to 51 inches; light brownish gray (10YR 6/2) very fine sandy loam, dark grayish brown (2.5Y 4/2) moist; common medium distinct masses of iron depletion, dark grayish brown (10YR 3/2) dry; massive; slightly hard, very friable, nonsticky and nonplastic; few very fine and few fine roots; many very fine and few fine and medim tubular pores; slightly effervescent; moderately alkaline (pH 7.9(; gradual wavy boundary. (0 to 15 inches thick)
B'kg--51 to 70 inches; light brownish gray (10YR 6/2) silty clay loam, dark grayish brown (10YR 4/2) moist; few medium distinct masses of iron depletion, very dark grayish brown (10YR 3/2) moist, massive; very hard, firm, moderately sticky and moderately plastic; few very fine and few fine and medium tubular pores; strongly effervescent; very few fine spots of calcium carbonate; slightly alkaline (pH 7.7).
TYPE LOCATION: Bingham County, Idaho; about 2.5 miles southwest of Thomas; 800 feet east and 600 feet south of the northwest corner of the northeast 1/4 section 20, T. 3 S., R. 34 E.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 13 to 20 inches
Particle-size control section averages - 18 to 27 percent clay
Profile effervescence - strongly to slightly effervescent (some horizons may be non-effervescent)
Average annual soil temperature - 44 to 47 degrees F.
Depth to high water table - 18 to 36 inches - months-March through October
A or Ap horizon
Hue - 2.5Y or 10YR
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 or 2
Reaction - slightly or moderately alkaline
Bw, Bkg, and Bg horizons
Hue - 10YR or 2.5Y
Value - 3 through 6 dry, 2 through 4 moist
Chroma - 2 or 3 dry or moist
Reaction - slightly or moderately alkaline
One or more buried A horizons are common. Some pedons are saline and/or salt-affected.
COMPETING SERIES: These are the Blueslide and Chiloquin series. Blueslide soils are noncalcareous throughout the profile. Chiloquin soils lack lime in the profile and lack redox features above a depth of 30 inches.
GEOGRAPHIC SETTING: The soils are on flood plains, recent alluvial fans, and low stream terraces at elevations of 4,200 to 6,300 feet. Slopes are less than 2 percent. The soils formed in alluvium dominantly from quartzite, sedimentary rocks, rhyolite, loessal materials, basalt, and soils formed therefrom. The climate is semiarid, with dry summers. Average annual precipitation is 9 to 16 inches, and the average annual temperature is about 42 to 45 degrees F. Average frost-free period is 80 to 126 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Ball and Heiseton soils and the Bannock and Wardboro soils. Ball and Heiseton soils are moderately coarse textured. Bannock soils have no mottles or saturation with water above a depth of 40 inches. Wardboro soils have loose sand and gravel at depths of less than 20 inches.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; moderate or moderately slow permeability. A fluctuating water table rises to a depth of about 1.5 feet for short periods unless drained. Some areas are flooded.
USE AND VEGETATION: Mostly cultivated under irrigation for hay, pasture, sugar beets, small grains, and potatoes. The dominant plants are bluebunch wheatgrass, rabbitbrush, three-tip sagebrush, big sagebrush, and streambank wheatgrass.
DISTRIBUTION AND EXTENT: The series is moderately extensive in the upper Snake River Valley and Tributary valleys in eastern Idaho and in southwestern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Bingham County (Blackfoot-Aberdeen Area), Idaho, 1940.
REMARKS: Diagnostic horizons and other features:
Mollic epipedon: the zone from 0 to 18 inches
Redox features: iron accumulations with depletions at 18 inches
Based on land use and potential native vegetation, the drainage clas and classification are most appropriate. The colors of the 18 to 21 inch horizon need checking for aquoll vs. xeroll placement.
Organic matter decreases irregularly with depth.