LOCATION COLVILLE WAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Fluvaquentic Endoaquolls
TYPICAL PEDON: Colville silt loam - cultivated. (Colors are for moist soil unless otherwise noted. (All textures are apparent field textures.)
Ap--0 to 9 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; moderate fine and medium granular structure; hard, friable, moderately sticky and slightly plastic; many roots; common fine pores; strongly effervescent; strongly alkaline (pH 8.6); abrupt smooth boundary. (6 to 11 inches thick)
A--9 to 17 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; moderate medium subangular blocky structure; hard, friable, moderately sticky and slightly plastic; common roots; common fine pores; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (7 to 11 inches thick)
Bg--17 to 27 inches; dark gray (5Y 4/1) silty clay loam, gray (10YR 6/1); few medium distinct yellowish brown (10YR 5/8) redox concentrations; gray (10YR 6/1) dry; weak coarse prismatic structure; very hard, friable, moderately sticky and moderately plastic; few roots; common fine pores; strongly effervescent; strongly alkaline (pH 8.6); clear wavy boundary. (6 to 10 inches thick)
Cg1--27 to 38 inches; grayish brown (2.5Y 5/2) silty clay loam, light gray (10YR 7/1) dry; few medium distinct yellowish brown (10YR 5/8) redox concentrations; massive; hard, friable, moderately sticky and moderately plastic; few roots; common fine pores; strongly effervescent; strongly alkaline (pH 8.5); clear wavy boundary. (6 to 11 inches thick)
Cg2--38 to 54 inches; gray (10YR 5/1) silty clay loam, light gray (10YR 7/1) dry; few fine distinct brown (7.5YR 4/4) redox concentrations; massive; very hard, firm, moderately sticky and moderately plastic; few roots; common fine pores; strongly effervescent; moderately alkaline (pH 8.4); clear wavy boundary. (12 to 18 inches thick)
Cg3--54 to 60 inches; gray (10YR 6/1) silt loam, white (10YR 8/1) dry; few fine and medium distinct brown (7.5YR 4/4) redox concentrations; massive; hard, friable, slightly sticky and slightly plastic; few roots; common fine pores; slightly alkaline (pH 7.8).
TYPE LOCATION: Stevens County, Washington; Road No. 576, 0.3 mile west of the railroad track and 75 feet north of a cultivated field in the northeast 1/4, northeast 1/4 of section 29, T. 35 N., R. 39 E., W.M.
RANGE IN CHARACTERISTICS:
Soil Temperature: mean annual soil temperature is 47 to 50 degrees F.
Rock fragments: less than 5 percent in the particle-size control section
Calcium carbonate: calcareous in all parts of the upper 40 inches.
Reaction: slightly alkaline to strongly alkaline.
Clay content: 25 to 35 percent in the particle-size control section
Sand: less than 15 percent (by weight) fine sand or coarser
Ap and A horizons
Value: 3 to 5 dry, 2 or 3 moist
Chroma: 1 or 2 dry or moist
Structure: weak or moderate granular
Bg horizon
Hue: 10YR, 2.5Y or 5Y,
Value: 5 to 7 dry, 4 to 6 moist
Chroma: 1 or 2 dry or moist
Structure: weak or moderate prismatic
Redox concentrations: few to common medium distinct
Cg horizon
Hue: 10YR, 2.5Y or 5Y
Value: 5 to 8 dry, 4 to 6 moist
Chroma: 1 or 2 dry or moist
Texture: silt loam or silty clay loam, some pedons are silty clay in the lower part
Redox concentrations: few to common medium distinct
COMPETING SERIES: These are the Gibbon, Kittitas, Pahranagat, and Paranat series. Kittitas soils have more than 15 percent exchangeable sodium in the mollic epipedon. Pahranagat soils have a mean annual soil temperature of 53 to 59 degrees F. Gibbon and Paranat soils do not have a cambic horizon
GEOGRAPHIC SETTING: Colville soils are on bottom lands along streams and drainage ways. Slopes are 0 to 3 percent. These soils formed in alluvium derived principally from argillite, schist, gneiss, granite, limestone, and dolomite. Elevations are 1,400 to 2,400 feet. The climate is characterized by warm, dry summers and cool, moist winters. The mean annual precipitation is 15 to 29 inches. The mean annual air temperature is 45 to 47 degrees F. The frost-free season is 100 to 125 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bridgeson, Chewelah, and Narcisse soils. Bridgeson soils are noncalcareous. Chewelah and Narcisse soils have more than 15 percent coarser than very fine sand in the control section.
DRAINAGE AND PERMEABILITY: Poorly drained; slow or very slow runoff; moderately slow permeability. A seasonal water table is at or near the surface during the spring. In the summer, the water table is 2 to 4 feet below the surface.
USE AND VEGETATION: Most areas are under cultivation and small grains are the principal crops. Many areas are used for hay or pasture. Native vegetation is water-tolerant grasses, black cottonwood, willows, quaking aspen, birch, cedar, wild rose, reeds, tules and rushes.
DISTRIBUTION AND EXTENT: Northern Washington; MLRA 43A. The series is moderate in extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Stevens County, Washington, 1913.
REMARKS: Diagnostic horizons and other features recognized in this pedon are:
Mollic epipedon from 0 to 17 inches
Cambic horizon from 17 to 27 inches
Redox concentrations from 17 to 60 inches