LOCATION LATAHCO IDEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, frigid Argiaquic Xeric Argialbolls
TYPICAL PEDON: Latahco silt loam-cultivated. (Colors are for dry soil unless otherwise noted.)
Ap--0 to 8 inches; dark gray (10YR 4/1) silt loam, black (10YR 2/1) moist; very weak thin or medium plates that part to weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; many very fine irregular pores; few uncoated silt grains; slightly acid (pH 6.5); abrupt smooth boundary. (6 to 10 inches thick)
A--8 to 13 inches; dark gray (10YR 4/1) silt loam, black (10YR 2/1) moist; weak fine and medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common fine and very fine roots; many fine and very fine tubular pores; few uncoated silt grains; neutral (pH 6.6); clear irregular boundary. (4 to 12 inches thick)
E1--13 to 17 inches; gray (10YR 5/1) silt loam, black (10YR 2/1) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine and very fine roots; many very fine tubular pores; many uncoated silt grains; very few soft small (less than 1 mm.) black bodies; neutral (pH 6.8); clear wavy boundary. (1 to 5 inches thick)
E2--17 to 20 inches; gray (10YR 6/1) silt loam (high in coarse silt), very dark gray (10YR 3/1) moist; few fine brownish redox concentrations; massive; soft, very friable, slightly sticky and slightly plastic; few fine roots; many fine and very fine tubular pores; common soft, small (less than 1 mm.) black bodies; neutral (pH 7.0); abrupt wavy boundary. (2 to 8 inches thick)
E/B--20 to 21 inches; horizon consisting of material like that in the E2 and Bt1 horizons. (0 to 2 inches thick)
Bt--21 to 26 inches; grayish brown (2.5Y 5/2), light brownish gray (2.5Y 6/2, rubbed) silty clay loam, dark gray (2.5Y 4/1) dark grayish brown (2.5Y 4/2, rubbed) moist; moderate medium prismatic structure parting to moderate angular blocky; very hard, firm, moderately sticky and moderately plastic; few fine roots; many very fine and fine tubular pores; continuous distinct very dark gray (10YR 3/1) clay films that are darker moist; many soft small (less than 1 mm.) black bodies; slightly alkaline (pH 7.4); clear smooth boundary. (5 to 7 inches thick)
Btk1--26 to 32 inches; grayish brown (2.5Y 5/2) light brownish gray (2.5Y 6/2, rubbed) silty clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium prismatic structure parting to moderate medium angular blocky; very hard, firm, moderately sticky and moderately plastic; few fine roots on peds; many fine and very fine tubular pores; continuous distinct very dark grayish brown (10YR 3/2) clay films, very dark gray (10YR 3/1) moist; many small (less than 1 mm in diameter) soft black bodies; noncalcareous matrix with thin seams and old root channels coated with white (10YR 8/1) lime; moderately alkaline (pH 7.9); clear smooth boundary. (0 to 8 inches thick)
Btk2--32 to 42 inches; grayish brown (2.5Y 5/2) light brownish gray (2.5Y 6/2, rubbed) silty clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium and coarse prismatic structure parting to moderate coarse angular blocky; very hard, firm, moderately sticky and moderately plastic; common fine to medium tubular pores; continuous distinct clay films on faces of peds and continuous prominent films in pores; few small black concretions; thin white (10YR 8/1) lime and seams and splotches in cracks and in channels, matrix is noncalcareous; moderately alkaline (pH 8.2); clear smooth boundary. (0 to 11 inches thick)
Btb--42 to 51 inches; light brownish gray (2.5Y 6/2) silt loam, grayish brown (2.5Y 5/2) moist; few fine distinct redox concentrations; weak very coarse prismatic structure; very hard, firm, moderately sticky and moderately plastic; few fine and medium tubular pores; continuous faint clay films on faces of peds, continuous prominent clay films in pores; slightly alkaline (pH 7.8); abrupt wavy boundary. (8 to 14 inches thick)
Cc--51 to 62 inches; light gray (2.5Y 7/2) silt loam, grayish brown (10YR 5/2) moist; many fine and medium distinct yellowish brown (10YR 5/6 and 5/4) redox concentrations, dark yellowish brown (10YR 4/4) and brown (10YR 4/3) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine and medium pores; many fine and medium black concretions; moderately alkaline (pH 8.0).
TYPE LOCATION: Benewah County, Idaho; about 4 miles north of Tensed, 300 feet west of Highway 95 at Benewah Creek road intersection; 920 feet west and 60 feet south of the northeast corner of the NE1/4 SE1/4 section 27, T.45N., R.5W.; (Latitude 47 degrees, 12 minutes, 40 seconds North and Longitude 116 degrees, 56 minutes, 48 seconds West; USGS Tensed Quadrangle).
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 41 to 47 degrees F.
Soil moisture control section - usually moist but are dry for 45 to 60 days in late summer and fall.
Mollic epipedon thickness - 11 to 22 inches
Depth to the argillic horizon - 17 to 35 inches
A horizon
Value - 2 to 5 dry, 1 to 3 moist
Chroma - 1 or 2 dry or moist
Textures - SIL, SICL
Clay content - 15 to 30 percent
Reaction - slightly acid or neutral
E horizon (EB horizon, when present)
Hue - 10YR or 2.5Y dry or moist
Value - 5 to 8 dry, 2 to 7 moist
Chroma - 1 to 3 dry, 1 to 4 moist
Texture - SIL or VFSL
Clay content - 8 to 22 percent
Redoximorphic features - few to common
Iron-manganese concretions - few to common
Reaction - slightly acid or neutral
Bt and Btb (Btk and Btc horizons, when present)
Hue - 2.5Y, 10YR or 7.5YR
Value - 4 to 6 dry, 3 to 5 moist
Chroma - 1 to 4 dry or moist
Texture - SIL, SICL
Clay content - 24 to 38 percent
Redoximorphic features - few to common
Iron-manganese concretions - few to common
Reaction - slightly acid to moderately alkaline
Btk horizon has seams, veins, and segregations of lime, but the matrix is always noncalcareous.
COMPETING SERIES: There are competing series.
GEOGRAPHIC SETTING: Latahco soils are on low terraces, flood plains, and drainageways associated with loess covered uplands. Slopes are 0 to 3 percent. The soils formed in alluvium from the surrounding loessal uplands. Elevation is 1,600 to 4,200 feet. The average annual precipitation is 18 to 35 inches. The frost-free period is 80 to 135 days. The average annual temperature is 40 to 46 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cald, Lovell, Moctileme and Thatuna. Cald soils lack albic and argillic horizons. Lovell soils have an ochric epipedon and a clayey B2t horizon. Moctileme soils have an ochric epipedon and are medial. Naff soils lack an albic horizon and are dry for 60 to 75 consecutive days in the summer. Thatuna soils lack redox depletions within the upper 30 inches and are dry for 60 to 80 consecutive days in late summer and early fall.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained; slow runoff; slow and moderately slow permeability. Occasional, brief flooding from February to April. Typically a perched water table is present from December through June. An apparent water table is also present.
USE AND VEGETATION: These soils are used mainly for cropland. Crops are wheat, barley, hay, pasture, and grass seed. Native vegetation includes perennial forbs and grasses, black hawthorn, common chokecherry, and ponderosa pine.
DISTRIBUTION AND EXTENT: Northern Idaho and eastern Washington. The series is of small extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Benewah County, Idaho, 1975.
REMARKS: Diagnostic horizons and features recognized in the pedon:
Mollic epipedon - The zone from the soil surface to 17 inches (Ap, A, and E1 horizons)
Albic horizon - The zone from 17 to 20 inches (E2 horizon)
Argillic horizon - The zone from 21 to 51 inches (Bt, Btk1, Btk2 and Btb horizons)
Particle-size control section - 21 to 41 inches (Bt and Btk1 and part of the Btk2 horizons)
Soil moisture regime - aquic/xeric
Soil temperature regime - mesic
CEC activity class based on associated soils.