LOCATION BOWNS IDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Xeric Paleargids
TYPICAL PEDON: Bowns loam -- on a 2 percent concave-concave east-facing slope at 3,155 feet elevation in rangeland. The surface has about 1 percent stone cover. (Colors are for dry soil unless otherwise noted.)
A--0 to 2 inches; pale brown (10YR 6/3) loam, dark brown (10YR 3/3) moist; moderate thick platy structure; slightly hard, very friable, slightly sticky and slightly plastic; few very fine roots; many fine vesicular and few fine tubular pores; slightly alkaline (pH 7.5); abrupt smooth boundary. (0 to 2 inches thick)
E--2 to 7 inches; light yellowish brown (10YR 6/4) loam, dark brown (10YR 3/3) moist; weak thin platy structure; soft, very friable, moderately sticky and slightly plastic; common very fine and fine roots; common very fine and fine vesicular and tubular pores; neutral (pH 7.2); abrupt wavy boundary. (2 to 5 inches thick)
2Bt1--7 to 15 inches; pale brown (10YR 6/3) silty clay loam, dark yellowish brown (10YR 3/4) moist; light brownish gray (10YR 6/2) silt coats on faces of peds; moderate medium prismatic structure parting to moderate medium subangular blocky; slightly hard, friable, moderately sticky and moderately plastic; common very fine and fine roots; common faint clay films on faces of peds and in pores; about 7 percent fine basalt gravel; neutral (pH 7.3); gradual wavy boundary.
2Bt2--15 to 20 inches; light yellowish brown (10YR 6/4) silty clay, dark yellowish brown (10YR 4/4) moist; strong medium prismatic structure parting to strong medium angular blocky; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; common very fine and fine tubular pores; continuous distinct clay films on faces of peds and in pores; about 5 percent basalt gravel; slightly alkaline (pH 7.5); clear smooth boundary. (Combined 2Bt horizon is 8 to 15 inches thick)
2Btkn--20 to 28 inches; yellowish brown (10YR 5/4) silty clay, dark yellowish brown (10YR 4/6) moist; moderate medium prismatic structure parting to strong fine angular blocky; hard, firm, moderately sticky and moderately plastic; common very fine and fine roots; few very fine and fine tubular pores; continuous prominent clay films on faces of peds and in pores; about 7 percent basalt gravel; about 10 percent very hard cicada krotovina; common large lime splotches and veins in lower part of horizon; strongly alkaline (pH 8.6); slightly saline; clear smooth boundary. (4 to 12 inches thick)
2Btnq--28 to 35 inches; very pale brown (10YR 7/3) loam, yellowish brown (10YR 5/4) moist; massive; slightly hard, friable, slightly sticky and slightly plastic; few very fine roots; few very fine tubular pores; about 10 percent basalt gravel; about 15 percent durinodes; slightly calcareous matrix with many large splotches and veins of very strongly calcareous soft powdery lime; strongly alkaline (pH 8.6); moderately saline; abrupt wavy boundary. (3 to 20 inches thick)
3R--35 inches; highly jointed and fractured basalt.
TYPE LOCATION: Ada County, Idaho; about 25 miles southwest of Orchard; about 2,500 feet north and 2,475 feet west of the southeast corner of section 35, T. 1 S., R. 3 E.; USGS Orchard quadrangle; (Latitude 43 degrees, 17 minutes, 33 seconds N. and Longitude 116 degrees, 03 minutes, 47 seconds W.)
RANGE IN CHARACTERISTICS:
Average annual soil temperature - 54 to 55 degrees F.
Depth to abrupt textural change - 2 to 7 inches
Depth to calcium carbonates - 10 to 22 inches
Depth to bedrock - 20 to 40 inches
Particle-size control section - 35 to 55 percent clay; 0 to 15 percent rock fragments
Moisture control section - moist less than 90 consecutive days when the soil temperature is greater than 47 degrees F.
E horizon
Value - 3 or 4 moist
Chroma - 3 or 4 dry or moist
Texture - L or SIL
Clay content - 14 to 22 percent
Rock fragments - 0 to 20 percent gravel, 0 to 15 percent cobble, 0 to 5 percent stones and 10 to 35 percent total
Reaction - slightly acid or neutral
2Bt horizon
Value - 5 or 6 dry, 3 or 4 moist
Value of silt coats - 6 or 7 dry
Chroma - 3 or 4 dry or moist
Texture - SICL, SIC or C
Clay content - 35 to 55 percent
Rock fragments - 0 to 10 percent gravel, 0 to 5 percent cobbles, 0 to 5 percent stones and 0 to 15 percent total
Reaction - neutral or slightly alkaline
2Btkn horizon
Value - 5 through 7 dry, 4 or 5 moist
Chroma - 4 or 6 dry or moist
Texture - SIC, SICL or C
Clay content - 27 to 45 percent clay
Rock fragments - 0 to 10 percent gravel, 0 to 5 percent cobbles, 0 to 5 percent stones and 0 to 15 percent total
Calcium carbonate content - 3 to 15 percent
Reaction - moderately alkaline or strongly alkaline
2Bknq horizon
Value - 7 or 8 dry, 5 or 6 moist
Chroma - 2 through 4 dry or moist
Texture - L or SIL
Clay content - 18 to 27 percent
Rock fragments - 5 to 15 percent gravel, 0 to 10 percent cobbles, 0 to 5 percent stones and 5 to 25 percent total
Calcium carbonate content - 5 to 15 percent
Durinodes - 0 to 20 percent
Reaction - moderately alkaline or strongly alkaline
COMPETING SERIES: These are the Acoma, Berdugo, Biscaro (T), Borda, Chardoton, Gooding, Hagata (T), Jowee, Locey (T), Lodico (T), Poall, Reba and Spangenburg series. Acoma, Berdugo, Borda, Brent, Chardoton, Gooding, Jowee, Poall, Reba, and Spangenburg soils are greater than 40 inches deep to bedrock. Biscaro and Hagata soils are over paralithic contacts and lack calcium carbonate. Locey and Lodico soils lack calcium carbonate and E horizons.
GEOGRAPHIC SETTING: Bowns soils are on lava flow lobes on shield volcanoes. Elevations range from 3,000 to 3,200 feet. Slopes are 0 to 15 percent. These soils formed in a thin mantle of loess mixed with colluvium from basalt over silty alluvium from loess and weathered volcanic ash. The mean annual precipitation ranges from 8 to 9 inches. The mean annual temperature is 52 to 53 degrees F. The frost-free period is 140 to 150 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Banbury, Chilcott, Catchell, Power and Purdam soils and the competing Chardoton soils. Power and Purdam soils lack bedrock at a depth of less than 40 inches. Catchell and Chilcott soils have a duripan at depths of 20 to 40 inches. Banbury soils are less than 20 inches deep to bedrock.
DRAINAGE AND PERMEABILITY: Well drained; slow through rapid runoff; very slow permeability.
USE AND VEGETATION: The Bowns soils are used mainly for range and some small areas are irrigated. Natural vegetation is Sandberg bluegrass, bottlebrush squirreltail, Thurber needlegrass, Wyoming big sagebrush and littleleaf horsebrush.
DISTRIBUTION AND EXTENT: Ada County, Idaho; MLRA 11.. These soils are inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Ada County, Idaho, 1977.
REMARKS: Diagnostic horizons and features recognized in this pedon:
Ochric epipedon - the zone from 0 to 7 inches (A and E horizons)
Abrupt textural change -
Argillic horizon - the zone from 7 to 28 inches (2Bt1, 2Bt2, and 2Btkn horizons)
Particle-size control section - the zone from 7 to 27 inches
Soil moisture regime - aridic bordering xeric
Of the 12,983 acres previously mapped as the Bowns soil, about 50 percent has been correlated to the Catchell series through the MLRA 11 update process and Orchard Training Area Project, 1999. Some areas still mapped as the Bowns series have tested high in electrical conductivity in the lower part of the argillic horizon which may indicate the presence of a natric horizon. Further investigation is needed during the update process.
The classification of this pedon has been revised from Xerollic Paleargids to Xeric Paleargids based on revision to Soil Taxonomy.