LOCATION CROWERS IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Calcic Pachic Haploxerolls
TYPICAL PEDON: Crowers silt loam -- on a 62 percent northwest-facing slope at 2,360 feet elevation in native rangeland. (When described on June 1, 1989, the soil was moist throughout. Colors are for air-dry soil unless otherwise stated).
A1--0 to 10 inches; very dark grayish brown (10YR 3/2) silt loam, black (10YR 2/1) moist; weak coarse subangular blocky structure parting to strong fine granular; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine roots throughout; many very fine irregular pores; neutral (pH 6.8); clear smooth boundary.
A2--10 to 17 inches; brown (10YR 4/3) silt loam, very dark grayish brown (10YR 3/2) moist; weak coarse subangular blocky structure parting to strong fine granular; slightly hard, very friable, nonsticky and nonplastic; many fine and very fine roots throughout; many very fine irregular pores; 5 percent gravel; mildly alkaline (pH 7.4); clear smooth boundary.
A3--17 to 27 inches; brown (10YR 4/3) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate medium granular; slightly hard, friable, nonsticky and slightly plastic; many fine and very fine roots throughout; many very fine irregular pores; 5 percent gravel; mildly alkaline (pH 7.4); clear smooth boundary. (combined thickness of A the horizons is 20 to 30 inches)
Bw--27 to 31 inches; brown (10YR 4/3) silt loam, very dark grayish brown (10YR 3/2) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots throughout; common fine and very fine tubular pores; 5 percent gravel and 5 percent cobbles; mildly alkaline (pH 7.8); clear irregular boundary. (4 to 8 inches thick)
2Bk1--31 to 41 inches; brown (10YR 5/3) very cobbly silt loam, dark brown (10YR 3/3) moist; weak coarse subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; common fine and very fine roots throughout; common fine and very fine tubular pores; strongly effervescent (5 percent calcium carbonate equivalent); lime disseminated and segregated in many very fine filaments and as coatings on coarse fragments; 15 percent gravel and 25 percent cobbles; moderately alkaline (pH 8.2); clear wavy boundary. (6 to 30 inches thick)
2Bk2--41 to 62 inches; brown (10YR 5/3) cobbly silt loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots throughout; common fine and very fine tubular pores; strongly effervescent (5 percent calcium carbonate equivalent); lime disseminated and segregated in many fine and medium seams and soft masses and as coatings on coarse fragments; 5 percent gravel and 10 percent cobbles; moderately alkaline (pH 8.4).
TYPE LOCATION: Nez Perce County, Idaho; about 8 miles south of Lewiston, about 170 feet north and 1600 feet west of the southeast corner of section 27, T.34 N., R.5 W. Latitude 46 degrees 56' 38" N, longitude 116 degrees 15' 11" W.
RANGE IN CHARACTERISTICS:
Mollic epipedon thickness - 22 to 34 inches (Organic matter content is less than 1 percent below the Bw horizon.) Average annual soil temperature - 50 to 54 degrees F Depth to 2Bk horizon - 28 to 36 inches
Particle-size control section (weighted averages) Clay content - 16 to 18 percent Coarse fragment content - 15 to 30 percent Silt content - greater than 50 percent
A horizon Value - 3 or 4 dry, 2 or 3 moist Chroma - 2 or 3 dry, 1 or 2 moist Gravel content, lower part - 0 to 5 percent Clay content, lower part - 12 to 16 percent
Bw horizon Value - 4 or 5 dry, 3 or 4 moist Chroma - 2 or 3, dry or moist Textures - SIL, CB-SIL Coarse fragment content - 5 to 25 percent Clay content - 16 to 22 percent Reaction - neutral or mildly alkaline
2Bk1 horizon Textures - CBX-SIL, CBV-SIL Coarse fragment content - 35 to 70 percent Clay content - 16 to 24 percent Calcium carbonate equivalent - 5 to 10 percent
2Bk2 horizon (absent in some pedons) Coarse fragment content - 15 to 35 percent Clay content - 16 to 24 percent Calcium carbonate equivalent - 5 to 10 percent
COMPETING SERIES: This is the Timentwa soil. The Timentwa soils have a duripan at 40 to 60 inches and have less than 50 percent silt throughout the particle size control section.
GEOGRAPHIC SETTING: Crowers soils are on north- and east-facing canyon sides. Slopes range from 45 to 80 percent. These soils formed in loess, with minor amounts of volcanic ash, over colluvium from basalt. Elevations are 740 to 2800 feet. Average annual precipitation is 13 to 16 inches, average annual temperature is 48 to 52 degrees F., and the frost free period is 160 to 190 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Limekiln and Linville series. Limekiln soils are shallow, have a loamy-skeletal particle-size control section, and are on south and west aspects of canyons. Linville soils lack secondary carbonates within 40 inches, have a fine-loamy particle size control section, and are on canyon slopes at higher elevations.
DRAINAGE AND PERMEABILITY: Well drained; slow or medium runoff when vegetated; moderate permeability.
USE AND VEGETATION: These soils are used for livestock grazing. Native vegetation is mainly Idaho fescue, prairie junegrass, bluebunch wheatgrass, threeflower avens, and penstemon.
DISTRIBUTION AND EXTENT: North central Idaho. The soils of this series are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES PROPOSED: Nez Perce County, Idaho. The name is from a nearby canyon.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon (Pachic feature) - The zone from the surface to 31 inches (A1, A2, A3, and Bw horizons).
Secondary carbonates (Calcic feature) - from 31 to 62 inches (2Bk horizons).
Particle-size control section - The zone from 10 to 40 inches (A2, A3, Bw, and upper part of the 2Bk1 horizon).