LOCATION BANNOCK IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Aridic Calcixerolls
TYPICAL PEDON: Bannock loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 6 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate very thin and thin platy structure parting to weak very fine granular; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine, few medium roots; many very fine interstitial and very fine and fine tubular pores; about 7 percent rounded gravel; slightly calcareous; moderately alkaline (pH 8.0); abrupt wavy boundary. (6 to 11 inches thick)
B2--6 to 11 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; weak fine and very fine subangular blocky structure parting to weak medium and very fine granular; hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; many very fine and common fine and medium tubular pores; about 9 percent rounded gravel; slightly calcareous, some pebbles slightly coated with calcium carbonate on the lower side; moderately alkaline (pH 8.0); clear wavy boundary. (4 to 7 inches thick)
B3--11 to 16 inches; light brownish gray (10YR 6/2) loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; many very fine, few fine tubular pores; about 10 percent rounded gravel; few worm channels and casts; slightly calcareous, most pebbles coated with calcium carbonate on the lower side; mildly alkaline (pH 7.7); clear wavy boundary. (2 to 8 inches thick)
C1ca--16 to 24 inches; pale brown (10YR 6/3) loam, dark grayish brown (10YR 4/2) moist; weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; many very fine, few fine tubular pores; about 10 percent rounded gravel; few worm channels and casts; slightly calcareous, most pebbles coated with calcium carbonate on the lower side; mildly alkaline (pH 7.7); clear wavy boundary. (2 to 8 inches thick)
IIC2ca--24 to 32 inches; pale brown (10YR 6/3) gravelly loam, dark grayish brown (10YR 4/2) moist; massive; hard, friable, slightly sticky and slightly plastic; common very fine and fine, few medium roots; many very fine tubular pores; about 25 percent rounded pebbles; strongly calcareous, few splotches and common fine veins of calcium carbonate; pebbles thickly coated with calcium carbonate on lower side; moderately alkaline (pH 8.2); clear wavy boundary. (3 to 9 inches thick)
IIIC3ca--32 to 36 inches; light brownish gray (10YR 6/2) very gravelly sandy loam, dark grayish brown (10YR 4/2) moist; massive; soft, very friable, slightly sticky and nonplastic; common very fine and fine, calcareous, pebbles thickly coated with calcium carbonate on lower side; moderately alkaline (pH 8.2); clear wavy boundary. (0 to 4 inches thick)
IVC4--36 to 45 inches; light brownish gray (10YR 6/2) very gravelly coarse sand; about 15 percent of sand is very dark gray; single grained; loose; common very fine and fine and few medium roots; many very sand is very dark gray; single grained; loose; common very fine and fine and few medium roots; many very fine interstitial pores; about 70 percent variously colored rounded pebbles, mostly quartzite; slightly fine interstitial pores; about 70 percent variously colored rounded pebbles, mostly quartzite; slightly fine interstitial pores; about 70 percent variously colored rounded pebbles, mostly quartzite; slightly calcareous, pebbles thickly coated with calcium carbonate on lower side; moderately alkaline (pH 8.1).
TYPE LOCATION: Bingham County, Idaho; about 2.3 miles east and 1 mile north of Wapello; 320 feet south and 204 feet east of the NW corner of the SW1/4 sec. 11, T.2S., R.36E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 41 degrees to 47 degrees F. and the mean annual summer soil temperature at depth of 20 inches ranges from 59 degrees to 66 degrees F. The soils are usually dry, and are dry for 45 to 80 consecutive days during the late summer. The mollic epipedon is 6 to 11 inches thick. The sola are 13 to 20 inches thick. Depth to the calcic horizon ranges from 13 to 20 inches. The calcic horizon contains 15 to 25 percent calcium carbonate. Between depths of 10 and 20 inches, or deeper, the soils is dominantly loam, ranging to silt loam or gravelly loam, and contains less than 18 percent clay, more than 15 percent particles coarser than very fine sand and less than 35 percent rock fragments. Stratification with coarser strata occurs below depths of 20 to 35 inches in some pedons. Depth to a contrasting layer of loose or nearly loose gravel and sand ranges from 25 to 40 inches. The A and B horizons range from moderately calcareous to noncalcareous but are calcareous when mixed to depth of 7 inches. They are mildly or moderately alkaline. The A, B, and C1 horizons have hue of 10YR in most pedons, ranging to 2.5YR.
The A1 or Ap horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3. It contains 1.2 to 2.5 percent organic matter.
The B horizon has value of 5 or 6 dry, 3 or 4 moist and chroma of 2 or 3. It is dominantly loam but is gravelly loam or silt loam in some pedons.
COMPETING SERIES: These are the Bock, Cokel, Eaglecone, Holden, McCammon, Packham, Paesl, Presto, Sasser and Stan series. Bock, Eaglecone and Stan soils lack a layer of loose gravel and sand above depth of 40 inches, and Stan soils are dominantly moderately coarse textured. Cokel and Holden soils have mean annual soil temperatures warmer than 47 degrees F. McCammon soils have bedrock at depths of less than 40 inches. Packham and Paesl soils lack calcic horizons, and the Packham soils have more than 35 percent rock fragments in the control section. Presto soils have loamy sand over silt loam or medium textures above depth of 40 inches. Sasser soils are moderately coarse textured in the upper part of the control section.
GEOGRAPHIC SETTING: The soils are on stream terraces and alluvial fans at elevations of 4,200 to 5,900 feet. Slopes range from 0 to about 10 percent. The soils formed mostly in medium-textured alluvium over gravel and sand. The alluvium is dominantly from quartzite and sedimentary rock sources but contain some rhyolitic, basaltic, and granitic materials. In places, the upper part may be eolian sediments. The climate is semiarid, with dry summers. Mean annual precipitation is 8 to 13 inches and the average annual temperature is about 40 degrees to 46 degrees F. Average frost-free period is 90 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Bock, Packham, Sasser, and Stan soils and the Hayeston soils. Hayeston soils lack mollic epipedons and calcic horizons.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability in the A and B horizons and very rapid in the gravel and sand.
USE AND VEGETATION: Mostly cultivated under irrigation for hay, pasture, potatoes, sugar beets, and small grains. The dominant native plants are big sagebrush, bluebunch wheatgrass, Sandberg bluegrass, cheatgrass, and squirreltail.
DISTRIBUTION AND EXTENT: The series is moderately extensive on the terraces of the upper Snake River Valley and the tributary valleys in eastern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Bannock County (Portneuf Area), Idaho, 1918.