LOCATION KIMAMA ID+WAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Calciargidic Argixerolls
TYPICAL PEDON: Kimama silt loam, rangeland. (Colors are for dry soil unless otherwise noted.)
A1--0 to 4 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2) moist; weak very thin platy structure that parts to weak very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and few fine roots; many very fine interstitial and tubular pores; slightly acid (pH 6.5); abrupt smooth boundary.
A2--4 to 8 inches; brown (10YR 5/3) silt loam, very dark grayish brown (10YR 3/2), dark brown (10YR 3/3) crushed moist; very weak medium prismatic structure that parts to weak very fine granular structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine and few medium roots; common very fine tubular pores; neutral (pH 6.6); clear smooth boundary. (Combined thickness of the A horizon is 5 to 18 inches)
Bt1--8 to 17 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; very weak medium prismatic structure that parts to moderate very fine and fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; many very fine tubular pores; few faint patchy clay films on vertical and horizontal faces of peds and in pores; few hard (cicada) krotovinas; neutral (pH 6.8); clear smooth boundary.
Bt2--17 to 27 inches; brown (10YR 5/3), pale brown (10YR 6/3), crushed, silt loam, brown (10YR 4/3) moist; moderate very fine and fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine and few fine and medium roots; common very fine tubular pores; few faint patchy clay films on vertical and horizontal faces of peds and in pores; many hard (cicada) krotovinas; neutral (pH 6.9); clear smooth boundary.
Bt3--27 to 33 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; moderate very fine subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; common very fine tubular pores; few faint clay films on faces of peds and in pores; common hard (cicada) krotovinas; slightly effervescent; slightly alkaline (pH 7.6); clear wavy boundary. (Combined thickness of the Bt horizon is 9 to 30 inches)
Bk1--33 to 43 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; weak fine and medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; common (cicada) krotovinas; violently effervescent, many fine veins and few coatings of lime; moderately alkaline (pH 7.9); clear wavy boundary. (5 to 20 inches thick)
Bk2--43 to 54 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; very weak medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; few (cicada) krotovinas; violently effervescent, many fine veins and few coatings of lime; moderately alkaline (pH 7.9); clear wavy boundary. (0 to 20 inches thick)
Bkb--54 to 64 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; very weak coarse subangular blocky structure; hard, friable, slightly sticky and slightly plastic; few very fine roots; many very fine tubular pores; few (cicada) krotovinas; strongly effervescent, common fine veins and few coatings of lime; moderately alkaline (pH 7.9); clear smooth boundary. (0 to 10 inches thick)
TYPE LOCATION: Blaine County, Idaho; 1.5 miles southeast of Minidoka; 2,480 feet south and 540 feet south of the southeast corner of sec. 18, T.8S., R.26E. Latitude - 43 degrees, 42 minutes, 28 seconds North; Longitude - 113 degrees, 27 minutes, 12 seconds West.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 49 to 55 degrees F.
Mollic epipedon - 7 to 18 inches thick
Depth to calcic horizon - 20 to 43 inches
A horizon (when mixed to depth of 7 inches)
Value of 4 or 5 dry, 2 or 3 dry
Chroma - 2 or 3 dry or moist
Organic matter content - 1 to 2 percent
Reaction - neutral to slightly alkaline.
Bt horizon
Value - 4 through 6 dry and 3 or 4 moist
Chroma - 2 through 4 dry or moist
Clay content - 18 to 25 percent
Reaction - neutral to moderately alkaline
Bk horizon
Value of 5 through 7 dry, 3 through 5 moist
Chroma of 2 through 6 dry or moist
Calcium carbonate equivalent - 15 to 25 percent
Texture - loam or silt loam
Hard nodules of soil material or cicada krotovinas - 0 to 20 percent
COMPETING SERIES: These are the Hamrub, Marley, Polecat, and Rockspring series. Hamrub soils have a duripan at 40 to 50 inches. Marley soils have fine textures in the lower part of the argillic horizon and have buried Bt horizons. Polecat soils have carbonates at 12 to 20 inches and a paralithic contact at 40 to 60 inches. Rockspring soils are 20 to 40 inches to a lithic contact.
GEOGRAPHIC SETTING: The soils are in drainageways, basins, slight depressions, and sideslopes associated with loess-covered basalt uplands plateaus, buttes, mesas, and structural benches. Elevations range from 3,000 to 4,500 feet in Idaho, and 1.500 to 3,400 feet in Washington. Slopes are 0 to 35 percent. These soils formed in local alluvium and loess. The climate is semiarid, with dry summers. Average annual precipitation is 8 to 12 inches, including 1 to 3 feet of snowfall; but most areas also receive runoff from adjacent slopes. Average annual temperature is 47 to 53 degrees. The frost-free period is 80 to 145 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Caliralls, Minidoka, Portino, Portneuf, Trevino, and Wipple series. Caliralls soils have greater than 15 percent fine sand or coarser in the particle-size control section. Minidoka, Portino, Portneuf, and Trevino soils lack a mollic epipedon and argillic horizon. Wipple soils have 45 to 60 percent clay in the particle-size control section and are 40 to 60 inches to lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; slow runoff; moderate to moderately slow permeability.
USE AND VEGETATION: Used mainly as cropland under irrigation for sugar beets, beans, small grains, hay, and pasture. The natural vegetation is Wyoming big sagebrush, basin wildrye, streambank wheatgrass, bluebunch wheatgrass, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Southern Idaho and Central Washington loess areas. The series is not extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Blaine County, Idaho, 1972.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - from the surface to 17 inches (A1, A2, and Bt1 horizons)
Argillic horizon - from 8 to 33 inches (Bt1, Bt2, and Bt3 horizons)
Calcic horizon - from 33 to 60 inches (Bk1, Bk2, and Bkb horizons)
Particle-size control section - the zone from 8 to 28 inches (Bt1, Bt2, and part of the Bt3 horizons)