LOCATION MINIDOKA IDEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Xeric Haplodurids
TYPICAL PEDON: Minidoka silt loam - cultivated, on a 3 percent slope. (Colors are for air- dry soil unless otherwise stated.)
Ap--0 to 6 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak fine granular structure; slightly hard, friable; many very fine to medium roots; many very fine tubular pores; strongly effervescent; mildly alkaline; gradual wavy boundary. (6 to 16 inches thick)
Bk--6 to 13 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable; many very fine to medium roots; many very fine tubular pores; strongly effervescent; moderately alkaline; abrupt smooth boundary. (6 to 21 inches thick)
Bkq1--13 to 20 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; massive; hard, firm; common very fine and fine roots; common very fine and fine roots; common very fine tubular pores; 25 percent durinodes; violently effervescent; moderately alkaline; gradual wavy boundary.
Bkq2--20 to 26 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; massive; hard, firm; common very fine and fine roots; common very fine tubular pores; 10 percent gravel-sized duripan fragments; 15 percent durinodes; violently effervescent; moderately alkaline; abrupt smooth boundary. (combined thickness of the Bkq horizon is 6 to 16 inches)
Bkqm--26 to 40 inches; white (10YR 8/2) indurated duripan, light gray (10YR 7/2) moist; extremely hard, extremely firm; many continuous silica-cemented laminations throughout duripan; violently effervescent; abrupt smooth boundary. (2 to 15 inches thick)
2R--40 inches; basalt.
TYPE LOCATION: Twin Falls County, Idaho; about 5 miles east of Castleford, Idaho; in the NW quarter of the NW quarter of the NW quarter of Section 25, T. 10 S., R. 14 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 47 to 53 degrees F.
Depth to duripan - 20 to 40 inches
Depth to bedrock - 40 to more than 60 inches
Depth to calcic horizon - 7 to 16 inches and are calcareous to the soil surface.
Particle-size control section - 10 to 18 percent total clay, 5 to 15 percent carbonate free clay, 3 to 15 percent fine sand or coarser.
A horizon
Value - 6 or 7 dry, 4 or 5 moist
Chroma - 2 or 3 dry or moist
Reaction - slightly or moderately alkaline
Calcium carbonate equivalent - 5 to 15 percent
Bk and Bkq horizons
Value - 6 through 8 dry, 4 through 6 moist
Chroma - 2 or 3 dry or moist
Calcium carbonate equivalent - 15 to 40 percent
Durinodes - 5 to 40 percent
Reaction - moderately alkaline or strongly alkaline
A B'k horizon underlies the duripan.
Value of 5 ot 6 moist
Texture - SIL or GR-SIL with 0 to 30 percent rock fragments
COMPETING SERIES: These are the Burke, Dolman, and Nyssa series. Burke and Nyssa soils lack a calcic horizon. Dolman soils lack secondary carbonates above a depth of 12 inches.
GEOGRAPHIC SETTING: Minidoka soils are on terraces and basalt plains. Slopes range from 0 to 12 percent. The soil formed in loess and alluvium from mixed sources. Elevation ranges from 2,000 to 5,000 feet. The average annual precipitation is about 8 to 11 inches. The average annual air temperature is about 45 to 52 degrees F. The frost-free period is 100 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Minveno, Portneuf, Scism and Vickery soils. Minveno soils are shallow to a duripan. Portneuf soils lack a duripan. Scism soils have a weakly cemented duripan. Vickery soils are noncalcareous in the upper part, and are fine-loamy. Minveno, Portneuf, Scism and Vickery soils occur on the same landscape position as the Minidoka soil.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff; moderate permeability.
USE AND VEGETATION: Minidoka soils are used for irrigated cropland, pastureland and rangeland. The principal crops grown are wheat, barley, potatoes, alfalfa hay, sugar beets, corn, corn silage and dry beans. The native vegetation is Wyoming big sagebrush, and Thurber needlegrass.
DISTRIBUTION AND EXTENT: Southcentral and southwestern Idaho. This series is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Minidoka Area, Idaho, 1923.
REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Ochric epipedon
Calcic horizon - the zone from 6 to 26 inches (Bk and Bkq horizons)
Indurated duripan - the zone from 26 to 40 inches (Bkqm horizon)
Particle-size control section - the zone from 10 to 26 inches (Bk, Bkq horizons)