LOCATION EGINBENCH IDEstablished Series
TAXONOMIC CLASS: Mixed, frigid Xeric Torripsamments
TYPICAL PEDON: Eginbench loamy coarse sand, cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; brown (10YR 5/3) loamy coarse sand, very dark grayish brown (10YR 3/2) moist; single grain; loose; many very fine, fine and medium roots; many very fine interstitial pores; about 5 percent fine pebbles; moderately alkaline (pH 8.0); abrupt smooth boundary. (7 to 13 inches thick)
AC--8 to 16 inches; brown (10YR 5/3) loamy coarse sand, very dark grayish brown (10YR 3/2) moist; common medium dark brown (7.5YR 3/4) mottles; single grain; loose; many very fine roots; about 5 percent fine pebbles; moderately alkaline (pH 8.2); clear wavy boundary. (6 to 17 inches thick)
C1--16 to 27 inches; light brownish gray (10YR 6/2) loamy coarse sand, dark brown (10YR 4/3) moist; many coarse dark brown (7.5 YR 3/2) mottles; single grain; loose; few very fine roots; many very fine interstitial pores; netural; (pH 7.2); gradual wavy boundary. (8 to 17 inches thick)
C2--27 to 39 inches; light brownish gray (10YR 6/2) loamy coarse sand, dark grayish brown (10YR 4/2) moist; single grain; loose; few very fine roots; many very fine interstitial pores; about 5 percent fine pebbles; netural (pH 6.7); diffuse wavy boundary. (8 to 22 inches thick)
C3--39 to 60 inches; coarse sand with about 10 percent fine pebbles; neutral (pH 6.7).
TYPE LOCATION: Madison County, Idaho; 5 miles west, 2.5 miles north of Rexburg; 635 feet west, 450 feet south of the northeast corner NW 1/4 SE 1/4 Section 7, T.6N., R.39E.
RANGE IN CHARACTERISTICS:
Soil temperature - 42 to 46 degrees F.
Summer Soil Temperature - 61 to 67 degrees F.
Depth to Watertable - 1 to 6 feet. Highest during the irrigation season. Watertable is artificially induced to allow subirrigation.
Reaction - neutral through moderately alkaline.
Control section - Upper part LFS, FS, LS, LCOS, COS.
Lower part LC0S, COS, less than 15 percent gravel.
A horizon - Value: 4 or 5 dry, 2 or 3 moist.
Chroma: 2 or 3 dry and moist.
AC horizon - Value: 4 or 5 dry, 2 through 4 moist.
Chroma: 2 or 3 dry and moist.
C horizon - Value: 5 or 6 dry, 2 through 5 moist.
Chroma: 1 through 3 dry and moist.
COMPETING SERIES: These are Benman, Bonnick and the Wolverine series. Benman soils are moderately deep to bedrock. Bonnick soils are excessively drained and have ore than 15 percent pebbles. Wolverine soils are calcareous throughout and lack a water table.
GEOGRAPHIC SETTING: Eginbench soils are on river terraces. These soils formed in mixed alluvium with an eolian mantle. Slopes are 0 to 2 percent. Elevations are 4500 to 5200 feet. The mean annual precipitation is 10 to 14 inches with 3 to 4 feet of snow in winter. The frost-free season is 90 to 120 days. Mean annual temperature is 41 to 45 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Blackfoot, Grassy Butte, St. Anthony and the competing Wolverine soils. Blackfoot soils are medium textured and are on flood plains. Grassy Butte soils are calcareous throughout and are on basalt plains. St. Anthony soils are on lower terraces and have more than 35 percent gravel in the control section. Wolverine soils are on established dunes at higher elevations.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Very slow runoff; rapid permeability. As more acres are converted to sprinkler irrigation the drainage is improved.
USE AND VEGETATION: Used for irrigated potatoes, small grains and hay.
DISTRIBUTION AND EXTENT: Southeast Idaho. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Madison County, Idaho, 1977.
REMARKS: Diagnostic horizons and features recognized in this soil are:
Organic carbon in the upper 10 inches is less than 0.6 percent.
Subirrigation is made possible by perching water on top of bedrock. An increase in the use of sprinkler irrigation is resulting in the lowering of the water table down slope from the sprinklers.