LOCATION BULLOCK SD+MT WYEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, frigid Aridic Leptic Natrustalfs
TYPICAL PEDON: Bullock fine sandy loam - on a 2 percent concave west-facing slope in native grass. (Colors are for dry conditions unless otherwise stated.)
E--0 to 4 inches; grayish brown (10YR 5/2) and light gray (10YR 6/1) fine sandy loam, dark grayish brown (10YR 4/2) moist; weak thin platy structure parting to weak fine granular; soft, very friable; common fine roots; neutral; abrupt smooth boundary. (2 to 4 inches thick)
Btn--4 to 9 inches; grayish brown (10YR 5/2) sandy clay loam, dark grayish brown (10YR 4/2) moist; strong coarse columnar structure parting to strong coarse and medium subangular blocky; very hard, friable, slightly sticky and slightly plastic; light gray (10YR 6/1) coats on caps of peds; thin continuous very dark grayish brown (10YR 3/2) shiny coats on all the faces of peds; few fine compressed roots; moderately alkaline; abrupt wavy boundary. (3 to 7 inches thick)
Btnk--9 to 12 inches; light brownish gray (2.5Y 6/2) sandy clay loam, dark grayish brown (2.5Y 4/2) moist; weak coarse prismatic structure parting to moderate medium and coarse subangular blocky; very hard, friable, slightly sticky and slightly plastic; thin continuous very dark grayish brown (2.5Y 3/2) shiny coats on the faces of peds; few fine compressed roots; few fine nests of gypsum and other salts; many medium and coarse accumulations of carbonate; strong effervescence; moderately alkaline; clear wavy boundary. (0 to 7 inches)
Bkz1--12 to 15 inches; light brownish gray (2.5Y 6/2) loam; grayish brown (2.5Y 5/2) moist; weak medium prismatic structure parting to moderate medium and fine subangular blocky; very hard, friable, slightly sticky and slightly plastic; few fine compressed roots; common fine nests of gypsum and other salts; common fine and medium accumulations of carbonate; strong effervescence; moderately alkaline; clear wavy boundary.
Bkz2--15 to 20 inches; light gray (2.5Y 6/1) clay loam, grayish brown (2.5Y 5/2) moist; weak medium and fine subangular blocky structure; hard, very friable; slightly sticky and slightly plastic; few fine compressed roots; common fine nests of gypsum and other salts; few fine accumulations and concretions of carbonate; strong effervescence; moderately alkaline; clear wavy boundary. (Combined Bk horizons 5 to 15 inches thick)
C--20 to 29 inches; light olive gray (5Y 6/2) very fine sandy loam, olive gray (5Y 5/2) moist; massive; hard, very friable; very few fine roots along horizontal bedding planes; few fine nests of gypsum and other salts; few fine concretions of carbonate; moderately alkaline; clear wavy boundary.
Cr1--29 to 43 inches; light gray (2.5Y 6/1) fine sandstone, gray (2.5Y 5/1) moist; sandstone easily crushed; fine roots along cracks from 2 to 7 inches apart; few fine concretions of carbonate; moderately alkaline; diffuse wavy boundary.
Cr2--43 to 60 inches; light gray (2.5Y 6/1) fine sandstone, gray (2.5Y 5/1) moist; sandstone easily crushed; few fine roots along the cracks and seams of the bedrock; common fine concretions of carbonate; strongly alkaline.
TYPE LOCATION: Harding County, South Dakota; about 13.5 miles south and 0.7 miles west of Camp Crook; about 1,600 feet north and 750 feet east of the southwest corner of sec. 15, T. 16 N., R. 1 E.
RANGE IN CHARACTERISTICS: Soft bedrock is at a depth of 20 to 40 inches and is easily dug with a spade or auger. Depth to gypsum and other visible salts ranges from 5 to 15 inches. Depth to the Btn horizon is less than 5 inches. Depth to carbonates ranges from 5 to 11 inches. SAR ranges from 13 to 20 in the natric horizon.
The E horizon has hue of 10YR or 2.5Y, value of 5 to 7 and 3 or 4 moist, and chroma of 1 or 2. It is typically fine sandy loam, but is loam, very fine sandy loam, loamy very fine sand or loamy fine sand in some pedons. It ranges from slightly acid to slightly alkaline.
The Btn horizon has hue of 10YR or 2.5Y, value of 5 or 6 and 4 or 5 moist, and chroma of 2 or 4. It typically is sandy clay loam, but is loam or clay loam in some pedons. It has moderate or strong columnar structure parting to moderate or strong fine to coarse subangular or blocky in the upper part and has weak to strong prismatic structure parting to moderate, medium, or coarse subangular or blocky in the lower part. It contains fine to coarse accumulations of carbonate and salts in the lower part of most pedons. It ranges from neutral to moderately alkaline in the upper part and slightly to strongly alkaline in the lower part.
The Bk horizon has hue of 10YR, 2.5Y or 5Y, value of 5 to 7 and 4 or 5 moist, and chroma of 1 to 4. It is clay loam, sandy clay loam, loam, or sandy loam. It has few to many, fine to coarse accumulations of carbonate. It has few to many fine accumulation of salts. It ranges from slightly to strongly alkaline.
The C horizon has hue of 2.5Y or 5Y, value of 4 to 8 and 3 to 6 moist, and chroma of 2 to 4. It is clay loam, sandy clay loam, silt loam, loam, fine sandy loam, sandy loam or very fine sand loam and in some pedons it is stratified. Typically, it has few to many, fine or medium accumulations of carbonate and fine accumulations of salts. It ranges from slightly to strongly alkaline. Some pedons do not have a C horizon.
The Cr horizon is soft sandstone or siltstone, or silty or clayey shale interbedded with soft sandstone. The bedrock is calcareous, but some layers do not have carbonates.
COMPETING SERIES: These are the Archin, Armitage, Hopsonville, Parchin, Rominell and Tisworth series. None these soils, except Hopsonville and Parchin, have bedrock at a depth of 20 to 40 inches. In addition, Archin soils have a combined A and E horizons more than 5 inches thick, Armitage soils have greater than 15 percent coarse fragments on the surface and Rominell soils are more alkaline in the A and Bt1 horizon. Hopsonville soils have carbonates in the Bt horizon, are very strongly alkaline in the Bt horizon and have an SAR of greater than 20 below a depth of 16 inches. Parchin soils are 5 inches or more to the base of the E horizon and the carbonates and visible salts are at greater depths.
GEOGRAPHIC SETTING: Bullock soils are on nearly level to steep uplands. Slope gradients range from 0 to 30 percent. The soils formed in residuum weathered from sandstone or silty and clayey shales interbedded with soft sandstone. Mean annual temperature ranges from 40 to 45 degrees F, and the mean annual precipitation ranges from l0 to l4 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the competing Parchin soils and the Absher, Blackhall, Cabbart, Gerdrum, Loburn, Marmarth, Rhame and Twilight soils. Parchin soils are on slightly higher parts of the microrelief with the Bullock soils. Absher, Gerdrum and Loburn series have a fine-textured natric horizon. Blackhall, Cabbart, Rhame and Twilight soils do not have a natric horizon. In addition, Blackhall and Cabbart soils have bedrock at a depth less than 20 inches. Blackhall, Cabbart, Marmarth, Rhame and Twilight soils are on upland ridges, crests, and knolls with the Bullock soils in saddles and toeslopes. Bullock soils are associated with Slickspots.
DRAINAGE AND PERMEABILITY: Well drained. Permeability is very slow or slow in the Btn horizon and moderate or moderately slow in the C horizon. Runoff is low to very high depending on slope.
USE AND VEGETATION: These soils are used mainly for range. Some areas are cultivated. Native vegetation is western wheatgrass, blue grama, buffalograss, saltgrass, needleandthread, sedges, saltbush, cactus and forbs.
DISTRIBUTION AND EXTENT: Northwestern South Dakota and possibly eastern Montana and southwestern North Dakota. This soil is extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Meade County, South Dakota, 1983.
REMARKS: The Bullock soils were mapped with the Absher soils in former surveys.
Diagnostic horizons and features recognized in this pedon: ochric horizon - the zone from the surface to a depth of about 4 inches; natric horizon - the zone from about 4 to 12 inches (Btn1 and Btnk horizon).
ADDITIONAL DATA: NSSL, Lab data 78P3124 for the typical pedon.