LOCATION RALLS WAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aridic Argixerolls
TYPICAL PEDON: Ralls very cobbly silt loam- rangeland. (Colors are for dry soil unless otherwise noted. All textures are apparent field textures).
A--0 to 10 inches; grayish brown (10YR 5/2) very cobbly silt loam, very dark grayish brown (10YR 3/2) moist; moderate fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; many medium and coarse tubular pores; 15 percent gravel, 5 percent cobbles and 5 percent stones; slightly alkaline (pH 7.6); gradual smooth boundary. (8 to 12 inches thick)
Bt--10 to 20 inches; brown (10YR 4/3) gravelly clay loam, dark brown (10YR 3/3) moist; moderate medium subangular blocky structure; hard, firm, moderately sticky and moderately plastic; common fine roots; few fine and very fine tubular pores; many distinct continuous clay films on faces of peds and on rock fragments; 20 percent gravel and 5 percent cobbles; slightly alkaline (pH 7.6); clear wavy boundary. (8 to 20 inches thick)
BCt--20 to 32 inches; yellowish brown (10YR 5/4) very gravelly silt loam, brown (10YR 4/3) moist; weak medium subangular blocky structure; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; few medium tubular pores; few faint discontineous clay films on peds and rock fragments; 25 percent gravel and 10 percent cobbles; slightly alkaline (pH 7.8); gradual smooth boundary. (0 to 20 inches thick)
C--32 to 60 inches; yellowish brown (10YR 5/4) very gravelly silt loam, dark yellowish brown (10YR 4/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few fine roots; common medium and fine tubular pores; 40 percent angular basalt gravel and 15 percent cobbles; moderately alkaline (pH 8.0).
TYPE LOCATION: Douglas County, Washington; 1,200 feet north and 1,200 feet east of southwest corner section 6, T. 23 N., R. 21 E.
RANGE IN CHARACTERISTICS: The mean annual soil temperature is 47 to 53 degrees F. These soils are dry more than one-half the time the soil temperature is above 41 degrees F, about 105 to 120 consecutive days in most years. The mollic epipedon is 10 to 20 inches thick. The particle-size control averages 15 to 35 percent rock fragments and 18 to 35 percent clay. Depth to bedrock is over 40 inches.
The A horizon has value of 4 or 5 dry, 2 or 3 moist and chroma of 2 or 3 dry or moist. Reactionb is slightly to moderately alkaline.
The Bt and BCt horizon has value of 4 or 5 dry, 3 or 4 moist and chroma of 3 or 4 dry, 2 to 4 moist. Texture is clay loam, silt loam or loam with 10 to 45 percent cobbles and gravel. It has continuous or patchy clay films. Reaction is slightly alkaline or moderately alkaline.
The C horizon has value of 5 to 7 dry, 3 to 5 moist and chroma of 3 or 4 dry or moist. Texture is clay loam or silt loam with 25 to 60 percent gravel and cobbles. Reaction is moderately alkaline or strongly alkaline. Soft powdery segregated lime is at a depth of 44 to 60 inches in some pedons.
COMPETING SERIES: These are the Bissell, Bjork, Cowiche, Dodes, Fernpoint, Hullsgulch (T), Indiano, Jerusalem (T), Margerum, Madras, Noslo, Orr, Pahrange, Quailridge (T), Quiero, Shoebend (T), Simcoe, Springmeyer, Truax, Uhaldi, and Wenatchee series. Bissell soils have 0 to 5 percent coarse fragments in the particle-size control section. Bjork, Indiano, Madras, Quiero, Simcoe, and Uhaldi soils have a lithic contact at a depth of 20 to 40 inches. Cowiche soils have 0 to 15 percent coarse fragments in the particle-size control section. Dodes, Pahrange, and Noslo soils have a paralithic contact at a depth of 20 to 40 inches. Galepi soils have a significant amount of volcanic ash in the particle-size control section. Jerusalem soils are more than 60 inches to the base of the argillic horizon, have 5 to 15 percent rock fragments and are slightly acid or neutral in the particle-size control sectionMargerum soils have 20 to 40 percent ash and pumice in the particle-size control section and the coarse fragments are dominantly pumice. Orr soils are sandy loam or sandy clay loam in the particle-size control section and are neutral or slightly acid throughout. Springmeyer and Truax soils are dry about 145 consecutive days and are slightly acid or neutral in the solum. Wenatchee soils have less than 15 percent coarse fragments in the particle-size control section. Fernpoint soils are 20 to 30 inches deep to contrasting extremely gravelly or cobbly sand or loamy sand. Quailridge and Hullsgulch soils formed in lacustrine sediments, contain lamella below the argillic horizon and have over 45 percent sand in the particle-size control section. Shoebend soils are 20 to 40 inches to a paralithic contact (granite) and 30 to 60 inches to a lithic contact (granite).
GEOGRAPHIC SETTING: These soils are on hillsides, canyon side slopes, and footslopes and side slopes of plateaus. Elevations are 400 to 3,300 feet. Slopes are 1 to 90 percent. These soils formed in colluvium from basalt mixed with some loess. They occur in a cool, dry semiarid climate. The mean annual precipitation is 9 to 12 inches. The average January temperature is 22 degrees F. and the average July temperature is 73 degrees F. The mean annual temperature is 49 degrees F. The frost-free season is 125 to 180 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bakeoven, Lickskillet, Renslow, and Zen soils. Bakeoven and Lickskillet soils are on uplands and areless than 20 inches deep to basalt. Renslow soils are on plateaus and hills and are coarse-silty. Zen soils are on plateaus and are 20 to 40 inches deep to a lithic contact.
DRAINAGE AND PERMEABILITY: Well drained; slow to very rapid runoff; moderately slow permeability.
USE AND VEGETATION: These soils are used for livestock grazing. The native vegetation is bluebunch wheatgrass, Idaho fescue, needleandthread, phlox, and Wyoming big sagebrush.
DISTRIBUTION AND EXTENT: Central Washington. MLRA 8. Ralls soils are of moderate extent.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Douglas County, Washington, 1978.
REMARKS: Diagnostic horizons and features recognized in this pedon are:
Mollic epipedon the zone from 0 to 20 inches
Argillic horizon the zone from 10 to 32 inches
Particle-size control section - the zone from 10 to 30 inches (Bt and part of the BCt horizon).