LOCATION TIMENTWA WAEstablished Series
TAXONOMIC CLASS: Ashy over loamy, glassy over mixed, superactive, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Timentwa very fine sandy loam, rangeland. (Colors are for dry soil unless otherwise stated.)
A1--0 to 2 inches; dark grayish brown (10YR 4/2) very fine sandy loam, very dark brown (10YR 2/2) moist; weak thin platy structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many fine tubular pores; 5 percent pebbles; slightly alkaline (pH 7.4); abrupt smooth boundary. (2 to 4 inches thick)
A2--2 to 9 inches; dark grayish brown (10YR 4/2) very fine sandy loam, very dark brown (10YR 2/2) moist; weak fine granular structure; soft, very friable, nonsticky and nonplastic; many very fine roots; many fine tubular pores; 10 percent pebbles; slightly alkaline (pH 7.4); clear smooth boundary. (7 to 9 inches thick)
A3--9 to 14 inches; dark grayish brown (10YR 4/2) very fine sandy loam, very dark grayish brown (10YR 3/2) moist; massive; soft, very friable, nonsticky and nonplastic; common very fine roots; few fine tubular pores; 10 percent pebbles; slightly alkaline (pH 7.8); clear smooth boundary. (0 to 8 inches thick)
Bw1--14 to 26 inches; brown (10YR 5/3) gravelly very fine sandy loam, dark brown (10YR 3/2) moist; weak medium subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; common very fine roots; many fine tubular pores; 15 percent pebbles; moderately alkaline (pH 8.0); clear wavy boundary. (10 to 16 inches thick)
Bw2--26 to 37 inches; brown (10YR 5/3) gravelly very fine sandy loam, very dark grayish brown (10YR 3/2) moist; weak fine subangular blocky structure; soft, very friable, slightly sticky and slightly plastic; few very fine roots; common fine tubular pores; 20 percent pebbles; moderately alkaline (pH 8.4); abrupt wavy boundary. (6 to 14 inches thick)
2Bk1--37 to 43 inches; grayish brown (2.5Y 5/2) gravelly fine sandy loam, dark grayish brown (2.5Y 4/2) moist; moderate subangular blocky structure; hard, firm, slightly sticky and slightly plastic; few very fine roots; few fine tubular pores; 25 percent pebbles; 5 percent cobbles, and 1 percent stones; strongly effervescent with lime coatings on pores; strongly alkaline (pH 8.6); abrupt wavy boundary. (5 to 8 inches thick)
2Bkq--43 to 47 inches; gray (10YR 5/1) very gravelly fine sandy loam, dark gray (10YR 4/1) moist; massive; very hard, very firm, nonsticky and nonplastic; few fine tubular pores; discontinuous weakly lime-silica cemented lenses 1/8 inch thick; 35 percent pebbles, 10 percent cobbles, and 1 percent stones; strongly effervescent; strongly alkaline (pH 8.6); clear smooth boundary. (2 to 7 inches thick)
2Bk2--47 to 60 inches; gray (10YR 5/1) very gravelly fine sandy loam, dark gray (10YR 4/1) moist; massive; hard, firm, slightly sticky and slightly plastic; few fine tubular pores; 35 percent pebbles, 10 percent cobbles, and 1 percent stones; strongly effervescent; strongly alkaline (pH 8.6).
TYPE LOCATION: Grant County, Washington, about 7 miles north of the town of Coulee City; 1,000 feet south and 2,570 feet east of the northwest corner of section 27, T.26N., R.28E.
RANGE IN CHARACTERISTICS: Th mean annual soil temperature is 47 to 51 degrees F. The soils are usually moist but are dry in all parts between the depths of 8 and 24 inches for 90 to 105 consecutive days following the summer solstice. The rock fragments are mostly basalt, and average 15 to 35 percent in the particle-size control section. The mollic epipedon is 20 to 30 inches thick. The upper 15 to 27 inches of the particle-size control section has an estimated moist bulk density of 1.10 to 1.40 g/cc, volcanic glass content of 30 to 60 percent, including 5 to 40 percent sand-size pumice 0.5 to 2.0 mm in diameter, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.15 to 0.40 percent, and 15-bar water retention of 5 to 10 percent for air dried samples. Depth to secondary lime ranges from 22 to 44 inches. Depth to the 2Bkq or 2Bkqm horizon ranges from 40 to 60 inches. Depth to basalt bedrock is 40 to 60 or more inches. Glacial rocks, some up to 100 feet in diameter, occur in some pedons and are commonly exposed at the surface.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 dry or moist. It is 0 to 10 percent coarse fragments in the upper part and 0 to 20 percent in the lower part. It is neutral or slightly alkaline.
The Bw horizon has hue of 10YR or 2.5Y, value of 4 through 6 dry, 3 or 4 moist and chroma of 2 through 4 dry or moist. It is fine sandy loam, very fine sandy loam, or loam and is gravelly or cobbly in some pedons. It is 5 to 25 percent pebbles and 0 to 10 percent cobbles. Reaction is neutral to moderately alkaline.
A 2Bw horizon is in some pedons. It has textures like the 2Bk horizon.
The 2Bk horizon has hue of 10YR or 2.5Y, value of 4 through 7 dry, 3 through 5 moist and chroma of 2 through 4 dry or moist. It is fine sandy loam, coarse sandy loam, sandy loam, or loam and is gravelly, very gravelly, or cobbly in some pedons. It is 10 to 35 percent pebbles, 0 to 20 percent cobbles, and 0 to 5 percent stones. Reaction is slightly alkaline to very strongly alkaline.
The 2Bkq or 2Bkqm horizon has hue of 7.5YR, 10YR, or 2.5Y, value of 5 through 7 dry, 3 through 5 moist, and chroma of 2 through 4 dry or moist. It is fine sandy loam, sandy loam, coarse sandy loam, or loam and is gravelly, very gravelly, cobbly, or very cobbly. It is 10 to 35 percent pebbles, 0 to 20 percent cobbles, and 0 to 10 percent stones. Reaction is moderately alkaline to very strongly alkaline.
COMPETING SERIES: This is the Willock series. The Willock series lacks carbonates.
GEOGRAPHIC SETTING: Timentwa soils formed in glacial till mixed with loess and volcanic ash in the upper part on till plains on basalt plateaus. Slopes are 0 to 70 percent. Elevations range from 1,300 to 3,200 feet. The average annual precipitation ranges from 12 to 15 inches. The mean January temperature is about 26 degrees F.; the mean July temperature is about 70 degrees F.; and the mean annual temperature is 46 to 49 degrees F. The frost-free season is about 110 to 170 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Argabak, Badge, Bakeoven, Benge, Colockum, Conconully, Dezellem, Duleylake, Emdent, Haley, Picard, and Siweeka series. Badge soils are on sideslopes. Argabak, Bakeoven and Colockum soils are on uplands. Benge, Haley and Picard soils are on outwash terraces and terrace escarpments. Conconully and Dezellem soils are on ground moraines. Duleylake soils are in basins on till plains. Emdent soils are in bottomlands and basins. Siweeka soils are on till plains. All of these soils lack a mollic epipedon greater than 20 inches thick. In addition, Badge soils are loamy-skeletal and have an argillic horizon. Bakeoven soils are less than 10 inches deep to a lithic contact. Benge and Haley soils are coarse-loamy over sandy or sandy-skeletal. Colockum and Duleylake soils are fine-loamy. Conconully and Picard soils lack secondary lime within 44 inches of the surface. Emdent soils are Halaquepts. Siweeka soils have duripan at 20 to 40 inches.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability above duric layer and slow through the duric layer (2Bkq).
USE AND VEGETATION: Used mainly for dryland grain production and livestock grazing. Native vegetation is bluebunch wheatgrass, Idaho fescue, Sandberg bluegrass, big sagebrush, green rabbitbrush, threetip sagebrush, arrowleaf balsamroot, silky lupine, low fleabane, and common yarrow.
DISTRIBUTION AND EXTENT: North central Washington. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Washington, 1978.
REMARKS: Diagnostic horizons and features recognized in this soil are a mollic epipedon from the surface to 37 inches, discontineous, weakly cemented layer from 43 to 47 inches, and secondary lime at a depth of 37 to 60 inches.
ADDITIONAL DATA: Characterization and partial data is available for this soil. NSSL pedon number 84P0167 and 89P0212. Glass count for very fine sand fraction is 18 to 27 percent. Estimated glass count for coarse silt and fine sand is 18 to 27 percent. Because of sand size pumice and coarse volcanic ash from Glacier Peak, the following are estimated glass counts for sand fractions - medium sand is 50 percent, coarse sand is 75 percent and very coarse sand is 80 percent glass. Calculated weighted average is 30 to 40 percent glass in the upper part of the particle-size control section.