LOCATION GEOCONDA WAEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Calcic Pachic Argixerolls
TYPICAL PEDON: Geoconda silty clay loam-cultivated on a 4 percent northwest facing slope at an elevation of 3,280 feet. (Colors are for dry soil unless otherwise noted)
Ap--0 to 7 inches; very dark gray (10YR 3/1) silty clay loam, black (10YR 2/1) moist; moderate fine and medium granular structure and moderate medium subangular blocky; hard, firm, sticky and plastic; many very fine roots; common very fine irregular pores; neutral (pH 6.8); abrupt smooth boundary. (6 to 9 inches thick)
A--7 to 11 inches; very dark gray (10YR 3/1) silty clay loam, black (10YR 2/1) moist; moderate medium subangular blocky structure; hard, firm, sticky, sticky and plastic; many very fine roots; many very fine irregular pores; neutral (pH 7.0); clear wavy boundary. (3 to 7 inches thick)
Bt1--11 to 19 inches; very dark gray (10YR 3/1) silty clay, very
dark brown (10YR 2/2) moist; moderate medium subangular blocky structure; extremely hard, very firm, very sticky and very plastic; common very fine roots; common very fine tubular pores; continuous thick clay films on faces of peds and lining pores; mildly alkaline (pH 7.6); clear wavy boundary. (4 to 10 inches thick)
Bt2--19 to 25 inches; dark grayish brown (10YR 4/2) silty clay,
very dark grayish brown (10YR 3/2) moist; strong medium angular blocky structure; extremely hard, very firm, very sticky and very plastic; common very fine roots; common very fine tubular pores; continuous thick stress cutans on faces of peds;clay films lining some pores; mildly alkaline (pH 7.6); clear wavy boundary. (4 to 10 inches thick)
Btk1--25 to 54 inches; brown (10YR 5/3) silty clay, dark brown
(10YR 3/3) moist; moderate medium and coarse subangular blocky structure; extremely hard, very firm, very sticky and very plastic; common very fine roots; common very fine irregular pores; continuous moderately thick stress cutans on faces of peds;clay films lining some pores; common lime coatings in pores and on faces of peds; strongly effervescent; moderately alkaline (pH 8.2) abrupt wavy boundary. (2 to 35 inches thick)
2Btk2--54 to 57 inches; brown (10YR 5/3) gravelly silty clay; dark brown (10YR 3/3) moist; moderate medium and coarse subangular blocky structure; extremely hard, very firm, very sticky and very plastic; few very fine roots; common very fine irregular pores, continuous moderately thick stress cutans on faces of peds;clay films lining some pores; common lime coatings in pores and on faces of peds; 25 percent pebbles and 5 percent cobbles; moderately alkaline (pH 8.4); abrupt irregular boundary. (2 to 10 inches thick)
3R--57 inches; basalt.
TYPE LOCATION: Asotin County, Washington; about 2 miles northeast of Anatone; 1,000 feet south and 2,600 feet west of northeast corner of sec. 19, T. 8 N., R. 46 E.
RANGE IN CHARACTERISTICS: The depth to lime is 20 to 38 inches. Depth to a lithic contact is more than 40 inches. The mean annual soil temperature is about 47 to 50 degrees F. These soils are usually moist, but are dry in all parts between the depths of 4 and 12 inches for 60 to 75 consecutive days following summer solstice. The particle-size control section is 35 to 50 percent clay. The mollic epipedon is 20 to 38 inches thick and includes part of the argillic horizon.
The A horizon has value of 3 to 4 dry and chroma of 1 or 2 dry or moist. Reaction is slightly acid or neutral.
The Bt has hue of 7.5YR or 10YR, value of 3 through 5 dry, 2 through 4 moist, and chroma of 2 through 4 dry or moist. It is neutral or mildly alkaline throughout.
The Btk horizon has value of 5 through 7 dry, 3 through 5 moist, and chroma of 2 or 3 dry or moist. It is gravelly silty clay, very cobbly clay loam, very gravelly clay loam, gravelly loam, or very gravelly loam. The Btk is moderately alkaline or strongly alkaline. A thin Bk horizon is in some pedons just above the basalt.
COMPETING SERIES: This is the Pataha series in another family. Pataha soils are fine-loamy.
GEOGRAPHIC SETTING: Geoconda soils are on basalt plateaus and have slopes of 3 to 30 percent. They formed in loess and materials weathered from basalt. Elevation ranges from 3,000 to 3,600 feet. Summers are warm and dry and winters are cool and moist. The average annual precipitation ranges from 17 to 20 inches. The mean annual air temperature is about 46 degrees F. Frost-free season is 110 to 130 days.
GEOGRAPHICALLY ASSOCIATED SOILS: They are the Gwinly, Mallory, Neconda, Powwahkee, and Rockly soils. Gwinly, Mallory, Neconda, and Rockly soils have lithic contact at a depth of less than 40 inches. Powwahkee soils are fine-silty.
DRAINAGE AND PERMEABILITY: Well drained; medium to rapid runoff, slow permeability.
USE AND VEGETATION: Used for cropland and wildlife habitat. The principle crops are small grains and grass. Native vegetation is Idaho fescue, bluebunch wheatgrass, Sandberg bluegrass, and rose.
DISTRIBUTION AND EXTENT: Southeast Washington. Series of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Asotin County, Washington, 1984.
REMARKS: Diagnostic horizons and features recognized in this pedon are a mollic epipedon from the surface to 25 inches, an argillic horizon from 11 to 57 inches, and a calcic horizon from 25 to 57 inches.