LOCATION DARLINGTON IDEstablished Series
TAXONOMIC CLASS: Loamy-skeletal, mixed, superactive, frigid Calcidic Haploxerolls
TYPICAL PEDON: Darlington very gravelly loam -- on a 1 percent, northwest-facing slope at 5,520 feet elevation in irrigated hayland. (Colors are for dry soil unless otherwise noted. When described on June 6, 1988, the soil was moist throughout).
Ap--0 to 7 inches; grayish brown (10YR 5/2) very gravelly loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common very fine and fine roots; few very fine tubular pores; 35 percent gravel, 2 percent cobbles; neutral (pH 7.0); clear smooth boundary. (4 to 11 inches thick)
A--7 to 14 inches; brown (10YR 5/3) very gravelly loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine and few medium roots; common very fine tubular pores; 35 percent gravel, 2 percent cobbles; neutral (pH 7.2); clear wavy boundary. (0 to 9 inches thick)
Bt--14 to 21 inches; brown (10YR 5/3) gravelly loam, dark brown (10YR 4/3) moist; weak medium prismatic structure parting to moderate fine subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine, and few medium roots; common very fine tubular pores; few faint clay films on faces of peds; 30 percent gravel, 2 percent cobbles; neutral (pH 7.3); clear wavy boundary. (6 to 16 inches thick)
Bw--21 to 33 inches; brown (10YR 5/3) very gravelly loam, dark brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and slightly plastic; common very fine and few medium and coarse roots; common very fine tubular pores; 35 percent gravel, 2 percent cobbles; slightly alkaline (pH 7.4); gradual wavy boundary. (8 to 12 inches thick)
2Bk1--33 to 44 inches; pale brown (10YR 6/3) extremely gravelly loamy sand, brown (10YR 4/3) moist; moderate medium subangular blocky structure; slightly hard, very friable, nonsticky and nonplastic; few very fine and fine roots; few very fine tubular pores; 55 percent gravel, 5 percent cobbles; thin lime coatings on undersides of coarse fragments; slightly alkaline (pH 7.5); clear wavy boundary. (10 to 25 inches thick)
2Bk2--44 to 60 inches; dark grayish brown (10YR 4/2) extremely gravelly loamy sand, very dark brown (10YR 2/2) moist; single grain, loose; few very fine roots; few very fine tubular pores; 55 percent gravel, 10 percent cobbles; thin lime coatings on undersides of coarse fragments; slightly alkaline (pH 7.6).
TYPE LOCATION: Butte County, Idaho; about 1.5 miles south of the Moore Diversion; about 1,600 feet west and 720 feet south from the northeast corner of section 16, T. 6 N. R. 25 E.
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 39 to 43 degrees F.
Mollic epipedon thickness - 11 to 15 inches
Reaction of profile - neutral or slightly alkaline
Depth to secondary carbonates - 25 to 35 inches
Control section: clay content - 15 to 22 percent
Rock fragments - 35 to 60 percent
A horizon
Value - 4 or 5 dry, 2 or 3 moist
Chroma - 2 or 3 dry and moist
Bt horizon
Value - 4 through 6 dry, 3 or 4 moist
Chroma - 3 or 4 dry and moist
Texture - GR-L, GRV-L
Coarse fragments - 30 to 50 percent
Bw horizon
Hue -2.5Y or 10YR
Value - 3 or 4 moist
Texture - GR-L, GRV-SL, GRV-L
Coarse fragments - 25 to 50 percent
2Bk horizon
Value - 4 through 6 dry, 2 through 4 moist
Chroma - 2 or 3 dry or moist
Texture - GRX-LS, GRV-LS, GRX-S
COMPETING SERIES: This is the Breitenbach series. Breitenbach soils have a calcic horizon and accumulations of silica.
GEOGRAPHIC SETTING: Darlington soils are on stream terraces and fan terraces. These soils formed in mixed alluvium. Slopes are 0 to 4 and elevations are 5,000 to 6,000 feet. The climate is cold and moist in winter and dry in summer. The average annual precipitation is 11 to 13 inches; average annual temperature is 38 to 42 degrees F.; and the frost-free period is 65 to 110 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Borah, Mooretown, Soelberg and Techick soils. Borah and Mooretown soils are on flood plains and are moderately well drained and somewhat poorly drained respectively. Soelberg and Techick soils are on terraces and have argillic horizons.
DRAINAGE AND PERMEABILITY: Well drained. Slow runoff. Permeability is moderate in the upper part and very rapid in the lower part.
USE AND VEGETATION: Irrigated cropland and hayland. Native vegetation is basin big sagebrush and bluebunch wheatgrass.
DISTRIBUTION AND EXTENT: East-central Idaho. These soils are not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Custer-Lemhi Counties, Idaho, 1999.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 14 inches (Ap and A horizons).
Cambic horizon - the zone from 14 to 33 inches (Bt and Bw horizons).
Particle-size control section - the zone from 10 to 40 inches (part of the A, the Bt, Bw and part of the 2Bk1 horizons).