LOCATION UHLIG WA+IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Vitrandic Haploxerolls
TYPICAL PEDON: Uhlig ashy silt loam, cultivated. (Colors are dry soil unless otherwise stated.)
Ap1--0 to 4 inches; dark gray (10YR 4/1) ashy silt loam, black (10YR 2/1) moist; weak fine and medium granular structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine irregular pores; moderately acid (pH 6.0); abrupt smooth boundary.
Ap2--4 to 10 inches; gray (10YR 5/1) ashy silt loam, very dark gray (10YR 3/1) moist; moderate thin and medium platy structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common fine irregular pores; slightly acid (pH 6.3); abrupt smooth boundary. (combined thickness of the Ap horizon is 8 to 20 inches)
A--10 to 18 inches; dark grayish brown (10YR 4/2) ashy loam, very dark brown (10YR 2/2) moist; weak medium subangular blocky structure; slightly hard, very friable, slightly sticky and slightly plastic; many very fine and fine roots; common very fine irregular pores; neutral (pH 6.6); clear wavy boundary. (4 to 10 inches thick)
2Bt1--18 to 32 inches; brown (10YR 5/3) loam, dark brown (10YR 3/3) moist; weak coarse prismatic structure parting to moderate medium subangular blocky structure; hard, firm, slightly sticky and slightly plastic; common fine roots; many very fine irregular pores; few faint patchy clay films on faces of peds and on surfaces along pores; neutral (pH 6.6); clear wavy boundary.
2Bt2--32 to 42 inches; pale brown (10YR 6/3) loam, brown (10YR 4/3) moist; weak coarse prismatic structure; slightly hard, friable, slightly sticky and slightly plastic; common fine roots; common fine irregular pores; few faint clay films on surfaces along pores; many nodules 1/4 to 3/8 inch in diameter that are brown (7.5YR 4/4) moist; neutral (pH 6.8); gradual wavy boundary. (combined thickness of the Bw horizon is 22 to 36 inches thick)
2C--42 to 60 inches; very pale brown (10YR 7/3) very fine sandy loam, brown (10YR 5/3) moist; massive; slightly hard, very friable, slightly sticky and nonplastic; few roots; many very fine and few fine interstitial pores; neutral (pH 6.8).
TYPE LOCATION: Spokane County, Washington; About 3 miles north of Millwood, WA; directly under power line about 1,000 feet north and 100 feet west of the end of Scott Road; 1,640 feet south and 1,220 feet east of the northwest corner of section 20, T. 26 N., R. 44 E.; USGS Spokane NE, Wash. topographic quadrangle; (Latitude 47 degrees, 44 minutes, 21 seconds N. and Longitude 117 degrees, 16 minutes, 41 seconds W.) NAD 83.
RANGE IN CHARACTERISTICS: The mean annual soil temperature at a depth of 20 inches ranges from 47 to 52 degrees F. The soils are usually moist but are dry in all parts between depths of 4 and 12 inches for 60 to 75 consecutive days during the summer and autumn. The upper 15 to 30 inches has an estimated moist bulk density of 1.20 to 1.40 g/cc, volcanic glass content of 5 to 20 percent, acid-oxalate extractable aluminum plus one-half of the acid-oxalate extractable iron of 0.4 to 1.0 percent, and 15-bar water retention of 5 to 10 percent for air dried samples. The mollic epipedon is 20 to 35 inches thick and may include part of the 2Bt or 2Bw horizon. The particle-size control section averages 5 to 18 percent clay and has more than 15 percent particles coarser than very fine sand.
The A horizon has value of 2 or 3 moist, 4 or 5 dry, and chroma of 1 or 2 dry or moist. Texture is ashy loam, ashy silt loam, or ashy very fine sandy loam and 5 to 18 percent clay. Gravel content is 0 to 5 percent. Reaction is moderately acid to neutral.
The 2Bt or 2Bw horizon has value of 3 to 5 moist, 5 to 7 dry, and chroma of 3 or 4 dry or moist. Texture is loam, silt loam, or very fine sandy loam in the upper part, and silt loam, loam, very fine sandy loam, or sandy loam in the lower part and 5 to 18 percent clay. It has none to few faint clay films. Gravel content is 0 to 5 percent in the upper part and 0 to 15 percent in the lower part. Reaction is slightly acid or neutral.
The 2C horizon, when present, has value of 3 to 5 moist and 5 to 7 dry, and chroma of 3 or 4 dry or moist. Texture is fine sandy loam, loam, sandy loam, or very fine sandy loam and has 5 to 15 percent clay. Reaction is neutral or slightly alkaline. Gravel content is 0 to 20 percent gravel. Secondary carbonates are present in some pedons.
A 3Btkb horizon is present in some pedons.
COMPETING SERIES: These are the Conconully, Deno (T), Falal (T), Phoebe, Safety, and Stevensseries. Similar soils with an isotic mineralogy class are the Donavan, Fourmound, Gibbs, Goldlake, Spokane, and Usk. Conconully, Donavan, and Stevens soils are 20 to 40 inches to Cd horizons. Deno soils have a lithic contact at 40 to 60 inches. Fanal and Goldlake soils are moderately well drained with redox concentrations in the lower part of the control section. Fourmound soils have mollic epipedons 10 to 20 inches thick and have a lithic contact at 40 to 60 inches. Gibbs soils have a lithic contact at 20 to 40 inches. Phoebe soils typically have sandy loam and fine sandy loam textures throughout and a substratum with sandy loam, loamy sand, or sand textures at a depth of 30 to 60 inches. Safety, Spokane, and Usk soils have a paralithic contact at 20 to 40 inches.
GEOGRAPHIC SETTING: Uhlig soils are on outwash terraces at elevations of 800 to 2,600feet. These soils formed from glaciofluvial deposits and alluvium mixed with loess and volcanic ash in the upper part. The climate is characterized by warm, dry summers and cool, moist winters. The mean annual precipitation ranges from 16 to 22 inches. The mean January temperature is about 28 degrees F.; the mean July temperature is about 66 degrees F.; and the mean annual temperature is 45 to 50 degrees F. The frost-free period is 100 to 140 days. In Idaho, the frost-free period is 150 to 175 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Athena, Calouse, Cheney, Hesseltine, Palouse, Thatuna, and Tucannon soils. Athena, Calouse, Palouse, Thatuna are fine-silty and are on loess hillslopes. Tucannon soils are fine-silty. and are on benches and plateaus of the channeled scabland. Hesseltine and Cheney soils are underlain by sand, gravel and cobbles at a depth of 20 to 40 inches and are on outwash plains.
DRAINAGE AND PERMEABILITY: Well drained; moderate permeability.
USE AND VEGETATION: These soils are used mainly for cropland and pasture. Small grains are principal crops. Native vegetation is Idaho fescue, bluebunch wheatgrass, common snowberry, and rose.
DISTRIBUTION AND EXTENT: Eastern Washington and Oregon, and western Idaho; MLRA 9. This series is moderately extensive.
MLRA OFFICE RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Spokane, Washington, 1961.
REMARKS: Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon - the zone from 0 to 32 inches (Ap1, Ap2, A and 2Bt horizons)
Cambic horizon - the zone from 18 to 42 inches (2Bt1 and 2Bt2 horizons) having oriented clay but no increase in clay percentage over the horizon above.
Particle-size control section - the zone from 10 to 40 inches (A, 2Bt1 and part of the 2Bt2 horizons)
Vitrandic feature - the zone from 0 to 18 inches (Ap1, Ap2, and Ap3 horizon)
This series is correlated to the PIPO/AGSP habitat type.
Classification revision as of 5/00 from coarse-loamy, mixed, mesic Pachic Haploxerolls to coarse-loamy, mixed, superactive, mesic Vitrandic Haploxerolls based on revision to Soil Taxonomy.
This pedon does not meet the criteria for an argillic horizon based on no increase in clay from the A horizon to the 2Bt1 horizon.
The discontinuity at the 2Bt1 horizon represents the limit of the vitrandic feature and the influence of air-fall volcanic ash and loess.
The 3Btkb horizon, when present, has been correlated to a clayey substratum phase.
ADDITIONAL DATA: Reference sample available; sample number S99WA-063-006; NSSL, Lincoln, NE.