LOCATION ST. ANDREWS WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Vitritorrandic Durixerolls
TYPICAL PEDON: St. Andrews ashy loam - cropland, wheat stubble, on a 2 percent slope at an elevation of 2,175 feet. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures and spot plate reaction is used for pH values.)
Ap--0 to 7 inches; grayish brown (10YR 5/2) ashy loam, very dark grayish brown (10YR 3/2) moist; moderate medium platy structure; soft, very friable, nonsticky and slightly plastic; many very fine and fine roots; common very fine irregular pores; 5 percent sand-size ash, 0.5 to 2.0 mm in diameter; 5 percent gravel; slightly alkaline (pH 7.5); clear wavy boundary. (5 to 10 inches thick)
A--7 to 14 inches; grayish brown (10YR 5/2) ashy loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; common very fine and fine roots; common very fine and fine tubular and few very fine irregular pores; common faint skeletans on faces of peds at the lowest two inches of the horizon; 5 percent sand-size ash, 0.5 to 2.0 mm in diameter; 5 percent gravel; slightly alkaline (pH 7.4); abrupt smooth boundary. (4 to 9 inches thick)
2Btk1--14 to 21 inches; grayish brown (2.5Y 5/2) silt loam, dark grayish brown (2.5Y 4/2) moist; strong medium prismatic structure; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; common fine tubular and few very fine irregular pores; many distinct light olive brown (2.5Y 5/4) clay films on faces of peds; 5 percent sand-size ash, 0.5 to 2.0 mm in diameter; 5 percent gravel; common fine filaments of calcium carbonate, strongly effervescent; 1 percent calcium carbonate equivalent; slightly alkaline (pH 7.4); clear wavy boundary.
2Btk2--21 to 29 inches; light brownish gray (2.5Y 6/2) silt loam, dark grayish brown (2.5Y 4/2) moist; moderate medium subangular blocky structure; hard, friable, slightly sticky and slightly plastic; common very fine roots; few very fine tubular and irregular pores; few faint light olive brown (2.5Y 5/4) clay films and few distinct stress surfaces on faces of peds; 10 percent sand-size ash, 0.5 to 2.0 mm in diameter; 10 percent gravel; few fine soft masses and disseminated calcium carbonate scattered throughout the horizon, violently effervescent; 1 percent calcium carbonate equivalent; moderately alkaline (pH 8.3); abrupt wavy boundary. (Combined thickness of the 2Btk horizons is 6 to 22 inches)
2Bkqm--29 to 33 inches; gray (2.5Y 5/1) moderately cemented duripan, black (5Y 2.5/2) moist; when crushed, gravelly sandy loam, massive; many distinct pinkish white (7.5YR 8/2) silica coatings on the laminar cap, pinkish gray (5YR 6/2) moist; very hard, very firm, nonsticky and nonplastic; few very fine roots in fractures spaced 4 to 10 inches apart; 15 percent gravel, 5 percent cobbles and 10 percent duripan fragments 2 to 75 mm in diameter; common distinct calcium carbonate films on 1 mm laminar cap surface and few fine irregular hard calcium carbonate concretions along with disseminated carbonates scattered below the laminar cap, violently effervescent; moderately alkaline (pH 8.4); abrupt wavy boundary. (1 to 16 inches thick)
3Cdk--33 to 60 inches; dark gray (2.5Y 4/1) gravelly coarse sandy loam, dark olive gray (5Y 3/2) moist; massive; very hard, very firm, nonsticky and nonplastic; few very fine roots; 20 percent gravel and 10 percent cobbles; common distinct calcium carbonate films on coarse fragments, strongly effervescent, and disseminated carbonates, very slightly effervescent; 5 percent calcium carbonate equivalent; slightly alkaline (pH 7.4).
TYPE LOCATION: Douglas County, Washington; approximately 12.6 miles east of Mansfield; about 550 feet west and 200 feet south of the northeast corner of section 1, T. 26 N., R. 27 E. (Latitude 47 degrees 47 minutes 09 seconds N, Longitude 119 degrees, 21 minutes 50 seconds W)
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 50 to 52 degrees F. These soils are dry in the moisture control section for one-half to three-fourths of the time when the soil temperature is above 41 degrees F. The mollic epipedon is 10 to 19 inches thick, it has moist bulk density of 1.15 to 1.45 g/cc, an estimated 30 to 60 percent volcanic glass, including 5 to 15 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, 15-bar water retention of 5 to 10 percent, 3 to 15 percent rock fragments, and an apparent field estimated clay content of 9 to 16 percent. The particle-size control section averages 18 to 27 percent clay and 15 percent or more fine sand or coarser, and less than 30 percent volcanic glass. Rock fragments average 3 to 15 percent with 3 to 15 percent pebbles and 0 to 10 percent cobbles. Depth to the argillic horizon and depth to secondary carbonates is 10 to 19 inches. Depth to a weakly to strongly cemented duripan is 20 to 40 inches. Depth to dense till is 21 to 50 inches.
The Ap horizon value is 4 or 5 dry and the chroma is 2 or 3 moist.
The A horizon chroma is 2 or 3 dry or moist. It is ashy loam or ashy silt loam. Reaction is neutral or slightly alkaline.
The 2Btk horizon hue is 10YR, 2.5Y, or 5Y. The value is 4, 5, or 6 dry and 3 or 4 moist. The chroma is 1, 2, or 3 dry and 2 or 3 moist. It is silt loam or loam. The calcium carbonate equivalent is 1 to 10 percent. Reaction is slightly alkaline to strongly alkaline.
The 2Bkqm horizon hue is 10YR, 2.5Y, or 5Y. The value is 5, 6, or 7 dry and 2.5, 3, or 4 moist. The chroma is 1 or 2 dry or moist. When crushed, the fine earth fraction textures to sandy loam, loam or coarse sandy loam. Calcium carbonate equivalent is 1 to 10 percent. Reaction is moderately alkaline or strongly alkaline.
The 3Cdk horizon hue is 10YR, 2.5Y, or 5Y. The value is 4 through 7 dry and 3 through 6 moist. The chroma is 1 or 2 dry or moist. It is gravelly coarse sandy loam, cobbly sandy loam, gravelly loam, or gravelly fine sandy loam. Rock fragments average 15 to 35 percent, with 10 to 20 percent gravel, 5 to 25 percent cobbles and 0 to 5 percent stones. Calcium carbonate equivalent is 1 to 10 percent and reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING: St. Andrews soils are in depressions on glaciated plateaus. Slopes are 0 to 8 percent. Elevation is 1,600 to 2,600 feet. They formed in loess mixed with volcanic ash over glaciolacustrine sediments over a duripan over glacial till. The climate is characterized by warm, dry summers and cool, moist winters. Average annual precipitation is 9 to 12 inches and average annual air temperature is 48 to 50 degrees F. Average January air temperature is about 27 degrees F., average July air temperature is about 71 degrees F., and frost-free season is 130 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the DelRio, Simsfield, Stubblefield and Touhey soils. Delrio soils are in outwash channels, depressions, swales, and on side slopes of glaciated plateaus. DelRio soils are ashy and do not have duripan. Simsfield soils are in glaciolacustrine bottoms and small depressions. Stubblefield soils are on ground moraines and are loamy-skeletal. Touhey soils are on side slopes and toe slopes of undulating till plains on plateaus.
DRAINAGE AND PERMEABILITY: Well drained, very slow to medium runoff; moderate permeability above the duripan.
USE AND VEGETATION: These soils are primarily used for dryland wheat and barley production. Small areas are used for livestock grazing. The potential native vegetation is bluebunch wheatgrass, basin wildrye, Wyoming big sagebrush, needleandthread, and Sandberg bluegrass.
DISTRIBUTION AND EXTENT: North Central Washington. The series is of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Washington, 1998.
REMARKS: Diagnostic features and horizons recognized in this pedon are a mollic epipedon from the surface to 14 inches, a fine-loamy argillic horizon with an average of 12.5 percent pebbles and 9 percent fine sand through very coarse sand (by weight) and with 1 percent calcium carbonate equivalent from 14 to 29 inches, and a moderately cemented lime-silica duripan from 29 to 33 inches over dense till. The particle size control section in the zone from 14 to 29 inches (the 2Btk1 and 2Btk2 horizons). Placement into fine-loamy family based on 2.5 x 15-bar water for average clay of 20 percent. The pumice is white, gray or yellowish brown. The percent field estimated pebbles by volume in the 2Btk horizons was not converted to percent by weight and is not listed on the lab data for this pedon, NSSL #90P0334. The gravel consists of ice rafted erratics and till rock fragments.
ADDITIONAL DATA: Partial NSSL lab data is available on this pedon, #90P0334.