LOCATION PORTNEUF IDEstablished Series
TAXONOMIC CLASS: Coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcids
TYPICAL PEDON: Portneuf silt loam, cultivated. (Colors are for air dry soil unless otherwise noted.)
Ap--0 to 9 inches; pale brown (10YR 6/3) silt loam, dark grayish brown (10YR 4/2) moist; very weak very fine granular structure; slightly hard, very friable, slightly sticky and
slightly plastic; common very fine and fine roots; few very fine tubular pores; slightly effervescent; slightly alkaline (pH 7.8); abrupt smooth boundary. (0 to 12 inches thick)
Bk--9 to 13 inches; pale brown (10YR 6/3) silt loam, brown (10YR 4/3) moist; very weak medium and coarse subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and few fine roots; common very fine and few fine tubular pores; few cicada krotovinas in the lower part; strongly effervescent; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 10 inches thick)
Bkq1--13 to 27 inches; very pale brown (10YR 8/3) silt loam, light brownish gray (10YR 6/2) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few very fine and fine roots; many dead roots on faces of peds; many very fine tubular pores; common hard, firm or very firm cicada krotovinas and subrounded nodules; strongly effervescent, common fine veins and soft masses of lime and coatings on krotovinas; moderately alkaline (pH 8.0); gradual smooth boundary. (6 to 16 inches thick)
Bkq2--27 to 42 inches; light gray (10YR 7/2) silt loam, grayish brown (10YR 5/2) moist; very weak medium and coarse subangular blocky structure; slightly hard, very friable; nonsticky and nonplastic; few very fine roots; dead roots on faces of peds; common very fine tubular pores; common hard, firm or very firm cicada krotovinas and subrounded nodules with softer matrix between the krotovinas; strongly effervescent, few fine masses and veins of lime; moderately alkaline (pH 8.2); gradual smooth boundary. (5 to 16 inches thick)
C--42 to 64 inches; very pale brown (10YR 7/3) silt loam, grayish brown (10YR 5/2) moist; massive; soft, very friable; nonsticky and nonplastic; few very fine roots; few very fine tubular pores; strongly effervescent; moderately alkaline (pH 8.4).
TYPE LOCATION: Minidoka County, Idaho, 6 miles west and 3 miles south of Paul; 3/4 mile south of Interstate Highway 86; about 1500 feet north and 50 feet west of the southeast corner of section 8, T. 10 S., R. 22 E.
RANGE IN CHARACTERISTICS:
Soil temperature - 49 to 53 degrees F.
Depth to calcic horizon - 6 to 15 inches
Thickness of calcic - 15 to 30 inches
Calcium carbonate equivalent - 15 to 30 percent
Particle size control section - 6 to 15 percent clay
Depth to bedrock - 40 to greater than 60 inches
A horizon
Value - 5 or 6 dry, 2 to 4 moist
Chroma - 2 or 3 dry or moist
Reaction - slightly alkaline or moderately alkaline
Bk horizon
Value - 5 through 7 dry, 4 through 6 moist
Chroma - 2 or 3 dry or moist
Reaction - slightly alkaline through strongly alkaline
Bqk horizons
Value - 6 through 8 dry, 4 through 6 moist
Chroma - 2 or 3 dry or moist
Consistence - slightly hard or hard, friable or firm Durinodes - 15 to 35 percent, hard or very hard, firm or very firm
Reaction - moderately alkaline or strongly alkaline
C horizon
Value - 6 through 8 dry, 4 through 6 moist
Chroma - 2 or 3 dry or moist
Salinity - less than 16 mmhos
Reaction - moderately alkaline or strongly alkaline
COMPETING SERIES: These are the Chijer and Hynes series. Chijer soils have loam texture in the particle-size control section. Hynes soils have a substratum at 40 to 60 inches that silty clay loam to very fine sandy loam texture.
GEOGRAPHIC SETTING: Portneuf soils are on fan terraces, basalt plains, terrace sideslopes and hillsides. Slopes range from 0 to 20 percent. Elevation ranges from 2,500 to 4,800 feet. The soil formed in loess and silty alluvium from mixed sources. The average annual precipitation is about 8 to 12 inches, the average annual air temperature is about 45 to 53 degrees F., and the frost free season is 100 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bahem, Darkbull, Declo, Heglar, Kimama, Minidoka, Pocatello, Portino, Scism, Sluka, Trevino and Wheeler soils. Bahem soils have less than 15 percent durinodes, and are less compact in the Bk horizon. Darkbull soils have a loamy-skeletal control section. Declo soils have a coarse-loamy control section. Heglar soils have a xeric moisture regime. Kimama soils have a mollic epipedon. Minidoka, Scism, and Sluka soils have duripans. Pocatello and Wheeler soils lack calcic horizons. Portino and Trevino soils have bedrock at less than 40 inches and less than 20 inches respectively. Bahem, Darkbull, Declo, Kimama, Minidoka, Pocatello, Portino, Scism, Sluka, and Trevino soils are on basalt plains and fan terraces. Heglar soils are on high fan terraces and hillsides. Wheeler soils are on steep hillsides.
DRAINAGE AND PERMEABILITY: Well drained, slow to medium runoff; moderate or moderately slow permeability.
USE AND VEGETATION: Portneuf soils are used for irrigated crops and rangeland. The main crops grown are potatoes, sugar beets, beans, small grains and hay. The natural vegetation is Wyoming big sagebrush, bluebunch wheatgrass and Thurber needlegrass.
DISTRIBUTION AND EXTENT: This series is extensive in southern Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Portneuf Area, Idaho, 1918.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - The zone from the surface to 9 inches
Durinodic Xeric feature - The zone from 13 to 42 inches - contains a layer greater than 7 inches thick with more than 20 percent durinodes (Bkq1 and Bkq2 horizons)
Calcic horizon - The zone from 13 to 42 inches (Bkq1 and Bkq2 horizons)
Particle size control section - 10 to 40 inches (Bw, Bkq1 and part of the Bkq2 horizons)