LOCATION CHINHILL IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Pachic Calcixerolls
TYPICAL PEDON: Chinhill silt loam, irrigated cropland; on a 1 percent slope at 5,125 feet elevation. When described on August 2, 1988, the soil was dry throughout. (Color is for dry soil unless otherwise noted.)
A1-- 0 to 2 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; moderate thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine irregular and tubular pores; 2 percent pebbles; slightly effervescent, disseminated lime; moderately alkaline (pH 8.0); abrupt smooth boundary. (1 to 5 inches thick)
A2-- 2 to 21 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine and medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and few fine tubular pores; 10 percent pebbles; slightly effervescent; disseminated lime; moderately alkaline (pH 8.0); abrupt smooth boundary. (19 to 25 inches thick)
Bk1-- 21 to 36 inches; gray (10YR 6/1) silt loam, very dark gray (10YR 3/1) moist; moderate fine and medium subangular blocky structure; hard, very friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; 2 percent pebbles; strongly effervescent; common fine irregularly shaped soft lime bodies and disseminated lime; moderately alkaline (pH 8.2); clear smooth boundary. (10 to 20 inches thick)
Bk2-- 36 to 60 inches; grayish brown (10YR 5/2) silt loam, dark grayish brown (10YR 4/2) moist; massive; slightly hard, very friable, slightly sticky and slightly plastic; 2 percent pebbles; strongly effervescent; common fine irregularly shaped soft lime bodies and disseminated lime; moderately alkaline (pH 8.2).
TYPE LOCATION: Caribou County, Idaho; about 1 mile west of the Grace Power Plant; about 50 feet east and 2,000 feet north of the southwest corner of sec. 20, T.10 S., R.40 E.; latitude 42 degrees 32 minutes, 19 seconds north, longitude 111 degrees, 49 minutes, 3 seconds west
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 43 degrees F
Thickness of mollic epipedon - 20 to 30 inches
Depth to secondary lime - 20 to 30 inches
Particle-size control section
Texture - SIL or L
Clay - 12 to 17 percent
Rock fragments - 0 to 10 percent
A horizons
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 1 through 3, dry or moist
Rock fragments - 0 to 10 percent
Calcium carbonate equivalent: 2 to 30 percent
Reaction: pH 7.8 to 8.4
Bk horizons
Value - 5 or 6 dry, 3 through 5 moist
Chroma - 1 through 3 dry or moist
Texture - SIL or L
Rock fragments - 0 to 10 percent
Calcium carbonate equivalent: 15 to 30 percent
Reaction: pH 7.8 to 8.4
COMPETING SERIES: This is the Bursteadt series. The Bursteadt soil has a seasonal high water table at 24 to 36 inches and a lithologic discontinuity at 25 to 35 inches.
GEOGRAPHIC SETTING: Chinhill soils are on stream terraces and fan remnants. Slopes range from 1 to 12 percent. Elevations range from 5,100 to 6,600 feet. The soil formed in mixed alluvium with some loess influence. The average annual precipitation ranges from 13 to 18 inches, the average annual air temperature is 39 to 43 degrees F and the frost free season is 70 to 95 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Arbone, Brifox (T), Iphil (T) and Rexburg soils. Arbone, Iphil and Rexburg soils have a coarse-silty particle-size control section and are not pachic. Brifox soils lack a mollic epipedon and average 35 to 60 percent clay in the particle-size control section. Rexburg and Iphil soils are on loess covered fan terraces and hillslopes above Chinhill soils. Arbone soils are on smooth slopes on tops of hills. Brifox soils are on hillsides and lake terraces.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Chinhill soils are used for irrigated and nonirrigated cropland and rangeland. Typical crops consist of small grains and alfalfa. The potential natural vegetation is Mountain big sagebrush, bluebunch wheatgrass and sod-forming grasses.
DISTRIBUTION AND EXTENT: Southeastern Idaho. This series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Caribou County, Idaho, 2008.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Pachic feature- the zone from the surface to 21 inches (A1 and A2 horizons)
Calcic horizon - the zone from 21 to 60 inches (Bk1 and Bk2 horizons)
Particle-size control section - the zone from 10 to 40 inches (part of the A2, Bk1 and part of the Bk2 horizons)