LOCATION BLACKNEST IDEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Xeric Haplargids
TYPICAL PEDON: Blacknest loam--rangeland. On a 3 percent slope, northeast aspect, 3,540 feet elevation. (Colors are for air dry soil unless otherwise noted.) When described on September 9, 1984 the soil was dry throughout.
A--0 to 5 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; moderate medium platy structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; many very fine and fine tubular pores; 10 percent gravel; neutral (pH 7.2); clear smooth boundary. (3 to 7 inches thick)
Bt1--5 to 13 inches; pale brown (10YR 6/3) sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; common very fine and fine roots; many very fine and fine tubular pores; few faint clay films on faces of peds and in pores; 5 percent gravel; neutral (pH 7.2); gradual wavy boundary. (6 to 8 inches thick)
Bt2--13 to 24 inches; pale brown (10YR 6/3) gravelly sandy clay loam, brown (10YR 4/3) moist; moderate medium subangular blocky structure; hard, friable, sticky and plastic; few very fine and fine roots; common very fine and fine tubular pores; common distinct clay films on faces of peds and in pores; 15 percent gravel; neutral (pH 7.3); gradual wavy boundary. (7 to 11 inches thick)
2Bw--24 to 30 inches; very pale brown (10YR 7/3) gravelly sandy loam, brown (10YR 5/3) moist; weak medium subangular blocky structure; slightly hard, friable; few fine and very fine roots; few fine and very fine tubular pores; 20 percent gravel; mildly alkaline (pH 7.6); gradual wavy boundary. (6 to 10 inches thick)
2Bk--30 to 60 inches; multi-colored extremely gravelly sand; massive; loose; calcium carbonate and silica coatings on undersides of gravel; strongly effervescent; moderately alkaline (pH 8.0).
TYPE LOCATION: Twin Falls County, Idaho; about 14 miles northwest of Buhl, Idaho; in the northwest 1/4, northwest 1/4, southeast 1/4, section 18, T. 8 S., R. 13 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 49 to 51 degrees F
Depth to sand and gravel - 20 to 40 inches
Depth to carbonates - 20 to 40 inches
Depth to bedrock - greater than 60 inches
A horizon
Value - 3 or 4 moist
Chroma - 2 or 3 dry or moist
Gravel - 0 to 10 percent
Bt horizons
Chroma - 3 or 4 dry or moist
Texture - SCL, L, CL, GR-SCL, GR-CL, and GR-L
Clay - 22 to 30 percent
Gravel - 5 to 30 percent
COMPETING SERIES: These are the Abgese, Ackley, Bluelight (T), Colbar, Esha (T), Eusbio (T), Greenbrae, Hardtrigger (T), Harsan (T), Hoosegow (T), Lankbush, Morfitt, Paulville, Seay, Sevy, Shawave, Sidlake (T), Stiles (T), Turria, Windypoint (T), and Zane series. Abgese soils have more than 35 percent medium and coarse sand in the control section. Ackley, Esha, Greenbrae, Hardtrigger (T), Harsan (T), Lankbush, Paulville, Sevy and Turria soils are greater than 40 inches to sand and gravel. Bluelight, Colbar and Sidlake (T) soils are less than 40 inches to bedrock. Eusbio (T) soils are moderately deep to a paralithic contact. Hoosegow (T), Lankbush, Morfitt and Turria soils lack carbonates above 40 inches. Paulville and Windypoint soils have a Bk horizon. Sevy and Zane soils have hues redder than 10YR. Shawave soils have average annual soil temperature of 53 degrees F. to 56 degrees F., and Bt horizons that are mildly or moderately alkaline.
GEOGRAPHIC SETTING: Blacknest soils are on old terraces. They formed in old alluvium from mixed sources. Slopes range from 1 to 15 percent. Elevation ranges from 3,000 to 4,000 feet. The average annual precipitation is 8 to 10 inches. The average annual temperature is 47 to 49 degrees F. The frost free season is 120 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Chuska, Dolman, Purdam, Rakane, Sluka, Tulch, and Yahoo soils are shallow to a duripan. Dolman, Purdam, Rakane and Sluka soils are moderately deep to a duripan. Dolman and Sluka soils lack argillic horizons and have coarse-silty control sections. Purdam soils have fine-silty control sections. Tulch soils do not have argillic horizons and have fine-silty control sections. They are on lower terraces.
DRAINAGE AND PERMEABILITY: Well drained, slow through medium runoff; moderately slow permeability in the upper part and very rapid in the lower part.
USE AND VEGETATION: Blacknest soils are used for rangeland and irrigated cropland. Native vegetation is Wyoming big sagebrush and Thurber needlegrass. Irrigated crops are mainly wheat, barley, beans, sugar beets, potatoes and alfalfa hay.
DISTRIBUTION AND EXTENT: This series is inextensive in south central Idaho.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Twin Falls County, Idaho, 1992.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Ochric epipedon - the zone from the surface to 5 inches (A horizon)
Argillic horizon - the zone from 5 to 24 inches (Bt1 and Bt2)
Particle size control section - 5 to 24 inches (Bt1 and Bt2 horizons) (Fails to meet criteria for strongly contrasting particle-size classes.)