LOCATION BOWMAN IDEstablished Series
TAXONOMIC CLASS: Coarse-loamy over sandy or sandy-skeletal, mixed, superactive, calcareous, mesic Typic Endoaquolls
TYPIFYING PEDON: Bowman silt loam, cultivated. (Colors are for dry soil unless otherwise noted.)
Apca--0 to 10 inches; dark gray (10YR 4/1) silt loam, black (10YR 2/1) moist; moderate medium granular structure; slightly hard, friable, slightly sticky, slightly plastic; many very fine roots and pores; moderately calcareous; moderately alkaline (pH 8.0); abrupt smooth boundary. (7 to 12 inches thick)
A12ca--10 to 18 inches; gray (10YR 5/1) silt loam, very dark gray (10YR 3/1) moist; few medium distinct brown mottles; weak fine subangular blocky structure; hard, friable, slightly sticky, slightly plastic; many very fine roots; many very fine tubular pores; slightly calcareous; mildly alkaline (pH 7.6); clear smooth boundary. (1 to 9 inches thick)
C1cag--18 to 32 inches; light gray (2.5Y 6/1) and light brownish gray (2.5Y 6/2) loam, gray (2.5Y 5/1) and grayish brown (2.5Y 5/2) moist; common medium distinct brown mottles; massive; hard, friable, slightly sticky, slightly plastic; common very fine roots; common very fine tubular pores; slightly calcareous; neutral (pH 7.2); clear smooth boundary. (3 to 18 inches thick)
C2g--32 to 38 inches; light gray (2.5Y 7/2) loam, light gray (2.5Y 6/1) and light brownish gray (2.5Y 6/2) moist; many medium prominent strong brown (7.5YR 5/8) mottles; massive; hard, friable, slightly sticky, slightly plastic; few very fine roots; common very fine tubular pores; neutral (pH 7.2); abrupt smooth boundary. (0 to 10 inches thick)
IIC3g--38 to 42 inches; light gray (N 7/) loamy fine sand, gray (N 5/) moist; massive; soft, very friable, nonsticky, nonplastic; few very fine roots; many very fine pores; moderately alkaline (pH 8.2); abrupt smooth boundary. (0 to 30 inches thick)
IIIC4g--42 to 48 inches; light gray (N 7/) sand, gray (N 5/) moist; single grained; loose; many very fine pores; mildly alkaline (pH 7.6); abrupt smooth boundary. (0 to 30 inches thick)
IVC5--48 to 60 inches; gravel, mostly of acid igneous origin.
TYPE LOCATION: Gem County, Idaho; about 2.7 miles southwest of Emmett; 1,100 feet west and 1,000 feet south of NE corner sec. 23, T.6N., R.2W.
RANGE IN CHARACTERISTICS: The mean annual soil temperature ranges from 49 degrees to 54 degrees F. and the mean summer temperature at a depth of 20 inches range from 68 degrees to 73 degrees F. The soils are saturated at some period when the soil temperature is above 41 degrees F. or are artificially drained. The upper part of the 10- to 40-inch control section is dominantly loam with less than 18 percent clay. Depth to loose noncalcareous sand, loamy sand or gravelly sand is less than 40 inches and is commonly about 30 inches. The upper part of the profile is moderately or weakly calcareous and the lower part is less calcareous or commonly noncalcareous. The organic carbon content is about 3 to 5 percent in the Ap horizon and it decreases regularly as depth increases. The mollic epipedon is 10 to 20 inches thick. The Ap horizon or the upper 7 inches when mixed ranges from 10YR 5/2 to 2.5Y 4/1 dry and from 10YR 3/2 to 2.5Y 2/1 moist. In some pedons, it contains segregations of lime. This horizon has moderate granular to weak subangular blocky structure. Distinct or prominent mottles related to wetness are in the lower part of the mollic epipedon or immediately below it. The horizon below the mollic epipedon has chroma of 2 or less in the matrix. Though dominantly loam between depths of 10 and 30 inches, some pedons have a thin layer of silt loam or moderately coarse or moderately fine texture. The C1cag horizon has weak coarse prismatic structure or is massive and it is friable or firm.
COMPETING SERIES AND THEIR DIFFERENTIAE: These are the Baldock, Balm, Black Canyon, Catherine, Draper, Gannett, Gilford, Hanska, McBeth, Moulton, Pajaro, St. Joe, and Wingville series. Baldock soils lack a mollic epipedon. Balm soils lack an aquic moisture regime or the colors associated with wetness of the Aquolls. Black Canyon soils have a strongly contrasting clayey over loamy control section. Catherine, Draper, and Wingville soils have a mollic epipedon thicker than 24 inches and lack strongly contrasting textures in the control section. Gannett, Gilford, Hanska, Jubilee, McBeth, and Pajaro soils lack strongly contrasting textures in the control section and Gannett, Gilford, Hanska, Moulton, and St. Joe soils have dominantly moderately coarse textures in the upper part of the control section.
SETTING: Bowman soils are in level or nearly level stream bottoms, alluvial fans, lake basins or very low terraces at elevations of 2,000 to 3,000 feet. Some areas are channelled and many are swales or depressions. The soils formed in alluvium or lacustrine deposits from mixed sources but mostly from acid igneous rocks. The climate is semiarid and has dry summers. Mean annual precipitation is 9 to 15 inches including 1 to 3 feet of snowfall. Mean freeze-free period is 115 to 152 days.
PRINCIPAL ASSOCIATED SOILS: These are the Competing Baldock, Black Canyon, Catherine, Draper, Moulton, and Wingville soils.
DRAINAGE AND PERMEABILITY: Naturally poorly drained but some areas are artificially drained; very slow runoff; moderate permeability. The water table is naturally high (1 to 3 feet), but has been lowered in many areas. Some areas are periodically flooded.
USE AND VEGETATION: Most is irrigated and used for production of hay, small grains, corn, and pasture. Some is used for native hay, pasture, and wildlife. Natural vegetation is chiefly water-loving grasses, sedges, and rushes, and includes iris, Great Basin wildrye, saltgrass, scattered shrubs, and along streams willow, cottonwood, alder, and hawthorn.
DISTRIBUTION AND EXTENT: Gem and Payette Counties, Idaho and possibly other parts of southern Idaho and southeastern Oregon. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Portland, Oregon
SERIES ESTABLISHED: Gem County Area, Idaho, 1962.
REMARKS: The soils were classified formerly as Humic Gley soils.