LOCATION DRAGOON WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, isotic, mesic Vitrandic Argixerolls
TYPICAL PEDON: Dragoon ashy silt loam - cultivated. (Colors are for dry soil unless otherwise stated. All textures are apparent field textures.)
Ap--0 to 7 inches; dark grayish brown (10YR 4/2) ashy silt loam, very dark brown (10YR 2/2) moist; weak medium granular structure; slightly hard, friable, slightly sticky and plastic; common fine roots; neutral (pH 6.6); abrupt smooth boundary. (6 to 10 inches thick)
A--7 to 11 inches; dark grayish brown (10YR 4/2) ashy loam, very dark brown (10YR 2/2) moist; massive; slightly hard, friable, slightly sticky and moderately plastic; common fine roots; few very fine pores; neutral (pH 6.6); abrupt smooth boundary. (4 to 8 inches thick)
Bt1--11 to 20 inches; brown (7.5YR 5/4) loam, dark brown (10YR 3/3) moist; moderate medium prismatic structure parting to weak subangular blocky; hard, firm, moderately sticky and moderately plastic; common fine roots; few very fine pores; few faint clay films on faces of peds and in pores; one wavy dark brown clay band 3/8 inch to 1/2 inch thick; neutral (pH 6.6); clear wavy boundary. (5 to 12 inches thick)
Bt2--20 to 27 inches; brown (10YR 5/3) loam, dark brown (7.5YR 3/4) moist; moderate medium prismatic structure; hard, firm, moderately sticky and very plastic; common fine roots; few very fine pores; common faint clay films in pores; neutral (pH 6.6); gradual wavy boundary. (2 to 8 inches thick)
2Cr--27 to 60 inches; disintegrated granite; massive, but crumbles readily into fine pebbles and coarse sand.
TYPE LOCATION: Spokane County, Washington; 500 feet north of center of northwest 1/4 of section 21, T. 24 N., R. 41E.
RANGE IN CHARACTERISTICS: Solum thickness and depth to a paralithic contact is 20 to 40 inches. These soils are usually moist, but are dry in all parts between depths of 4 and 12 inches for 60 to 75 consecutive days following the summer solstice. The upper 7 to 14 inches has an estimated volcanic glass content of 5 to 20 percent and an acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.4 to 1.0 percent. Mean annual soil temperature at a depth of 20 inches is estimated to be 47 to 52 degrees F. The mollic epipedon is 10 to 18 inches thick. The control section has 0 to 15 percent coarse fragments. The soils are slightly acid or neutral throughout. Some pedons have stony or very stony surface layers.
The A horizon has value of 4 or 5 dry, 2 or 3 moist, and chroma of 2 or 3 moist and dry.
The Bt horizon has hue of 7.5YR or 10YR, value of 4 through 6 dry, 3 or 4 moist, and chroma of 3 or 4. It is heavy silt loam, heavy loam, sandy clay loam, or light clay loam.
Some pedons have a B3 or C horizon of very gravelly or gravelly loamy sand or sandy loam.
COMPETING SERIES: These are the Gibbs and Glenrose series. The Gibbs soils are moderately deep to a lithic contact. The Glenrose soils are very deep.
GEOGRAPHIC SETTING: Dragoon soils are on foothills, ridgetops, and mountain side slopes at elevations of 2,000 to 3,000 feet. Slopes are 0 to 90 percent. These soils formed in material weathered from granitic rocks, gneiss, or schist and have a thin mantle of volcanic ash and loess. These soils occur in a continental climate with dry summers and cool, moist winters. Average annual precipitation is 15 to 21 inches, average January temperature is 25 degrees F, average July temperature is 68 degrees F, and mean annual temperature is 45 to 49 degrees F. The frost-free season is 100 to 140 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Cheney and Reardan soils. Cheney soils lack an argillic horizon. Reardan soils have a fine-textured argillic horizon.
DRAINAGE AND PERMEABILITY: Well drained; slow to rapid runoff; moderate permeability.
USE AND VEGETATION: Used for woodland, cropland, watershed, wildlife habitat and recreation. Cultivated areas are used for the production of small grains and alfalfa. Native vegetation is ponderosa pine and Douglas-fir, with an understory of Idaho fescue, bluebunch wheatgrass, Sandberg bluegrass, and arrowleaf balsamroot.
DISTRIBUTION AND EXTENT: Eastern Washington. Series is of moderate extent.
MLRA OFFICE RESPONSIBLE: Bozeman, Montana
SERIES ESTABLISHED: Spokane County, Washington, 1964.
REMARKS: Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 11 inches, an argillic horizon from 11 to 27 inches, and a paralithic contact at 27 inches. Estimated base saturation (sum of cations) is less than 75 percent in some part of the upper 30 inches.