LOCATION BENWY WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Calciargidic Argixerolls
TYPICAL PEDON: Benwy silt loam; rangeland; on a 10 percent northeast-facing slope at an elevation of 2,280 feet. (Colors are for dry soil unless otherwise stated.)
A--0 to 10 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; moderate fine granular structure; soft, very friable, nonsticky and slightly plastic; many very fine, common fine roots; many very fine tubular pores; 5 percent basalt gravel; neutral (pH 7.0); abrupt wavy boundary. (4 to 14 inches thick)
AB--10 to 18 inches; brown (10YR 5/3) silt loam, dark brown (10YR 3/3) moist; moderate fine subangular blocky structure; slightly hard, friable, nonsticky and slightly plastic; many very fine roots; common very fine tubular pores; 10 percent basalt gravel; neutral (pH 7.2); clear wavy boundary. (0 to 27 inches thick)
Bt--18 to 33 inches; yellowish brown (10YR 5/4) gravelly silt loam, dark yellowish brown (10YR 4/4) moist; moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine, fine roots; few very fine tubular pores; few faint clay films on peds and on coarse fragments; 15 percent basalt gravel; slightly alkaline (pH 7.8); clear wavy boundary. (10 to 18 inches thick)
Btk--33 to 45 inches; light yellowish brown (10YR 6/4) gravelly silt loam, yellowish brown (10YR 5/4) moist; strong medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common very fine roots; few very fine tubular pores; 15 percent basalt gravel; few faint clay films on peds and on coarse fragments; strongly effervescent; many fine irregular seams of soft lime; moderately alkaline (pH 8.4) abrupt wavy boundary (9 to 16 inches thick)
2Bkqm--45 inches; indurated duripan; violently effervescent.
TYPE LOCATION: Kittitas County, Washington; about 13 miles southeast of Kittitas off the old Milwaukee Railroad line; 1,600 feet south and 1,600 feet east of the northwest corner of section 14, T. 16 N., R. 21 E.; USGS Boyleston Topographic quadrangle; Latitude 46 degrees 52 minutes 36 seconds N. and Longitude 120 degrees 09 minutes 36 seconds W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 47 to 54 degrees F. These soils are dry more than half the time in the moisture control section when the soil temperature at a depth of 20 inches is above 40 degrees F. The particle-size control section averages 18 to 28 percent clay and more than 15 percent particles larger than very fine sand in the fine earth fraction and has 0 to 15 percent rounded basalt gravel and cobbles. The mollic epipedon ranges from 10 to 15 inches in thickness. Depth to secondary lime deposits range from 24 to 38 inches. Depth to the duripan ranges from 40 to more than 60 inches and is underlain by basalt, fanglomerate, sandstone, or siltstone.
The A horizon has a value of 4 or 5 dry and chroma of 2 or 3 moist. Reaction is neutral or slightly alkaline.
The AB horizon has a value of 4 or 5 dry, 3 or 4 moist and chroma of 3 or 4 dry and moist. Texture is silt loam or loam and averages 0 to 10 percent gravel. Reaction is neutral or slightly alkaline.
The Bt horizon has value of 4 to 6 dry, 3 or 4 moist and chroma of 3 or 4 dry and moist. Texture is loam, silt loam, or clay loam and has 0 to 20 percent gravel. Reaction is neutral, slightly alkaline or moderately alkaline.
The Btk or Bk horizon has a value of 4 to 8 dry, 4 to 6 moist and chroma of 2 to 4 dry, 3 or 4 moist. Texture is a loam, silt loam, or clay loam and has 5 to 20 percent gravel and 0 to 5 percent cobbles. Reaction is slightly alkaline to strongly alkaline. Clay content is typically less than 28 percent, but some pedons range up to 35 percent immediately above the duripan.
Some pedons have a very gravelly loam Bkq horizon above the indurated duripan.
COMPETING SERIES: These are the
Axford,
Babbington,
Brogan (T),
Caliralls,
Drybed,
Haw,
Polly and
Zen series.
Axford soils 40 to 60 inches to paralithic contact (basalt); 27 to 35 percent clay in pscs
Babbington soils 27 to 35 percent clay in pscs; lacks a duripan (2Bkqm horizon)
Brogan soils lack rock fragments in pscs; 15 to 25 inches to secondary carbonates
Caliralls soils 40 to more than 60 inches to lithic contact (basalt); lack a duripan (2Bkqm horizon); 15 to 25 percent rock fragments and 25 to 33 percent clay in pscs
Drybed soils 8 to 20 inches to secondary carbonates; 27 to 35 percent clay in pscs; lack a duripan (2Bkqm horizon)
Haw soils lack a duripan (2Bkqm horizon); less than 5 percent rock fragments in pscs
Polly soils 15 to 25 inches to secondary carbonates and base of argillic horizon; 25 to 35 percent clay in pscs; lack a duripan (2Bkqm)
Zen soils 20 to 40 inches to lithic contact (basalt)
GEOGRAPHIC SETTING: Benwy soils are on structural benches, highly dissected fan terraces, hillslopes, backslopes, summits, and footslopes and toeslopes of plateaus. Slopes are 0 to 45 percent. These soils formed in loess, colluvium, and alluvium from loess and basalt over cemented gravels and cobbles underlain by basalt, sandstone, or siltstone. These soils occur in depositional positions at elevations of 1,200 to 3,400 feet. These soils are in a semiarid climate with warm, dry summers and cool, moist winters. The mean annual precipitation is 9 to 12 inches. The mean January temperature is about 25 degrees F. and the mean July temperature is about 69 degrees F. The mean annual temperature is 46 to 52 degrees F. The frost-free season is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cheviot, Clerf, Grinrod, and Wipple soils on side slopes; Renslow soils on north-facing slopes; Vantage and Bakeoven soils in eroded and remnant positions on the same structural benches; Selah; and Terlan soils. Cheviot and Clerf soils are loamy-skeletal. Clerf and Wipple soils are clayey-skeletal. Renslow soils lack an indurated 2Ckqm layer and are coarse-silty. Vantage soils are clayey-skeletal with a lithic contact at 10 to 20 inches. Bakeoven soils are loamy-skeletal with a lithic contact at 4 to 10 inches. Selah soils are 20 to 40 inches to an indurated 2Bkqm. Terlan soils are 10 to 20 inches to an indurated duripan.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff; moderate permeability above the duripan, and very slow within the duripan.
USE AND VEGETATION: These soils are used for livestock grazing, wildlife habitat, and limited irrigated cropland. Native vegetation is bluebunch wheatgrass, Sandberg bluegrass, and big sagebrush.
DISTRIBUTION AND EXTENT: Eastern Kittitas and southern Douglas County, Washington. MLRA 8. Series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Kittitas County, Washington, Yakima Training Center, 1994.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon - the zone from 0 to 10 inches
Argillic horizon - the zone from 18 to 45 inches
Secondary carbonates - the zone from 33 to 45 inches
Indurated duripan - the zone beginning at 45 inches
ADDITIONAL DATA: Partial laboratory data available NSSL Number 83P4434-4437.