LOCATION COWICHE WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Argixerolls
TYPICAL PEDON: Cowiche loam - cultivated. (Colors are for dry soil unless otherwise stated.)
Ap1--0 to 3 inches; grayish brown (10YR 5/2) loam, very dark grayish brown (10YR 3/2) moist; moderate very thin platy structure; soft, very friable, slightly sticky and slightly plastic; many fine roots; neutral; abrupt smooth boundary.
Ap2--3 to 10 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak medium granular structure; soft, very friable, slightly sticky and slightly plastic; common fine roots; few fine tubular pores; neutral; clear wavy boundary. (The A or Ap horizon is 7 to 10 inches thick)
AB--10 to 20 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak medium prismatic structure; slightly hard, friable, sticky and plastic; few fine roots; few fine tubular pores; neutral; clear wavy boundary. (0 to 12 inches thick)
Bt--20 to 29 inches; yellowish brown (10YR 5/4) loam, dark yellowish brown (10YR 3/4) moist; moderate medium subangular blocky structure; hard, firm, sticky and plastic; few fine roots; few fine tubular pores; few thin and very thin clay films in pores and on faces of peds; neutral; clear wavy boundary. (6 to 30 inches thick)
BC1--29 to 35 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; few fine tubular pores; mildly alkaline; abrupt wavy boundary. (0 to 10 inches thick)
BC2--35 to 45 inches; pale brown (10YR 6/3) very fine sandy loam, brown (10YR 4/3) moist; massive; soft, very friable, nonsticky and nonplastic; few fine roots; mildly alkaline; clear wavy boundary. (0 to 12 inches thick)
2Bk--45 to 60 inches; brown (10YR 5/3) loamy fine sand, dark brown (10YR 3/3) moist; massive; hard, firm, nonsticky and nonplastic; few fine roots; segregated lime on upper boundary of horizon and in root channels; violently effervescent; moderately alkaline.
TYPE LOCATION: Yakima County, Washington; 6 miles northeast of Naches, about 2,000 feet east and 1,280 feet south of the northwest corner of sec. 27, T. 15 N., R. 18 E.
RANGE IN CHARACTERISTICS: The sola range from 30 to 60 inches thick. Depth to bedrock is greater than 40 inches. These soils are usually dry 105 to 120 days in all parts between depths of 4 and 12 inches when the soil temperature is more than 41 degrees F. The average annual soil temperature at a depth of 20 inches ranges from 47 to 55 degrees F. The upper 20 inches of the argillic horizon averages 15 to 25 percent particles coarser than very fine sand including 0 to 5 percent rock fragments. The lower part of the argillic horizon contains 0 to 5 percent coarse fragments. The mollic epipedon is 10 to 20 inches thick.
The A and AB horizons have value of 4 or 5 dry and chroma of 2 or 3 dry or moist. It has weak to moderate structure. This horizon is neutral or mildly alkaline.
The Bt horizon has value of 5 through 7 dry, and chroma of 3 or 4 dry or moist. It is heavy silt loam in the upper part and silt loam, heavy loam, clay loam, or sandy clay loam in the lower part. This horizon has moderate to strong blocky structure. It is neutral or mildly alkaline.
The 2Bk horizon, where present, has value of 5 or 6 dry, 3 or 4 moist, and chroma of 2 or 3 moist and dry or is multicolored. It is loamy fine sand, very fine sandy loam, sandy loam, or loamy sand and has 0 to 15 percent coarse fragments. It is mildly alkaline or moderately alkaline. Some pedons have a 2C horizon with similar color and texture that lack secondary line.
The 2Cr layers, where present, are sandstone or schist.
COMPETING SERIES: These are the Bissell, Bjork, Dodes, Indiano, Margerum, Pahrange, Ralls, Simcoe, Springmeyer, Uhalde, and Wenatchee series. Bissell soils are micaceous throughout. Bjork, Dodes, Indiano, Pahrange, Simcoe, and Uhalde soils have bedrock at a depth of 20 to 40 inches. Margerum soils have 15 to 35 percent coarse fragments, dominantly pumice, in the particle-size control section. Ralls soils have 15 to 35 percent basalt fragments in the particle-size control section. Springmeyer and Wenatchee soils have 5 to 35 percent coarse fragments in the particle-size control section.
GEOGRAPHIC SETTING: The Cowiche soils are at elevations of 1,000 to 4,800 feet on mountains and foothills. Slopes are 0 to 70 percent. These soils formed in loess over residuum from sandstone, or schist. The climate is semiarid with an average annual precipitation of 9 to 12 inches. These soils have hot, dry summers and cold, moist winters; average annual temperature is 49 degrees F., average January temperature is 29 degrees F., average July temperature is 70 degrees F., and average frost-free season is 135 to 185 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bjork, Colockum, Renslow, and Yaxon soils. Bjork soils are shallow to bedrock. Colockum and Renslow soils have secondary lime in the B horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for cropland, range, and wildlife habitat. Under irrigation the soil is used for production of orchards, vineyards, or hay and pasture. Native vegetation is bluebunch wheatgrass, Idaho fescue, arrowleaf balsamroot, lupine, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: Central Washington. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Yakima County, Washington, 1947.
REMARKS: Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 20 inches and an argillic horizon from 20 to 29 inches.