LOCATION LARVIE SDEstablished Series
TAXONOMIC CLASS: Very-fine, smectitic, mesic Aridic Leptic Haplusterts
TYPICAL PEDON: Larvie clay - on a slightly convex slope of 4 percent in native grass. When described the soil was dry throughout. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; gray (10YR 5/1) clay, dark grayish brown (10YR 4/2) moist; moderate fine and medium subangular blocky structure with a weak thin crust in upper part; very hard, friable, slightly sticky; cracks 1/2 to 1 inch wide; strong effervescence; slightly alkaline; clear smooth boundary. (3 to 6 inches thick)
Bss--4 to 12 inches; light gray (10YR 6/1) clay, grayish brown (10YR 5/2) moist; weak medium blocky structure; extremely hard, very firm, very sticky and very plastic; cracks 1/2 to 1 inch wide; few intersecting slickensides; tongues of dark gray (10YR 4/1) material; strong effervescence; moderately alkaline; gradual wavy boundary. (6 to 12 inches thick)
Bkss1--12 to 17 inches; gray (10YR 6/1 and 5/1) clay, grayish brown (10YR 5/2) moist; weak coarse blocky structure; extremely hard, extremely firm, very sticky and plastic; cracks 1/2 inch wide; few intersecting slickensides; few tongues of dark gray (10YR 4/1) material extend into horizon; common medium soft accumulations of carbonate; strong effervescence; moderately alkaline; gradual wavy boundary.
Bkss2--17 to 26 inches; reddish gray (10R 6/1) clay, weak red (10R 4/2) moist; weak fine and medium blocky structure; extremely hard, very firm, very sticky and very plastic; few intersecting slickensides; many medium soft accumulations of carbonate; strong effervescence; moderately alkaline; gradual smooth boundary. (Combined Bkss horizons is 5 to 16 inches thick.)
Cr--26 to 36 inches; reddish gray (10R 6/1) soft clay shale; breaks into blocky rock fragments; very hard and brittle; few medium soft accumulations of carbonate in upper 3 inches; strong effervescence; moderately alkaline.
TYPE LOCATION: Mellette County, South Dakota; about 8 miles north and 1 mile west of Cedar Butte; 1,100 feet east and 1,840 feet north of southwest corner of sec. 18, T. 43 N., R. 31 W.
RANGE IN CHARACTERISTICS: The depth to mudstone or clay shale bedrock ranges from 20 to 40 inches. Clay content exceeds 60 percent in most horizons. Gilagi microrelief is in most areas of the soil. The soil contains carbonates throughout and is slightly or moderately alkaline throughout.
The A horizon has hue of 10YR or 7.5YR, value of 4 to 6 and 3 or 4 moist, and chroma of 1 or 2.
The Bss horizon has hue of 10YR to 10R, value of 4 to 6 and 4 or 5 moist, and chroma of 1 to 3. Some pedons have accumulations of gypsum.
The Bkss horizon has hue of 7.5YR to 10R, value of 5 to 7 and 4 to 6 moist, and chroma of 1 to 3. It contains from 5 to 20 percent calcium carbonate equivalent. Some pedons have accumulation of gypsum and other salts.
Some pedons have a C horizon that is multi-colored and reflects the varigated color of the mudstone.
The Cr horizon is soft clay shale or mudstone.
COMPETING SERIES: These are the Kyle, Pierre, Swanboy, Wasa, Winler, Whitewater, and Twotop series. Kyle, Pierre, Swanboy, Wasa, Winler, and Twotop soils have yellower hue in the lower part of the profile. In addition, Kyle, Swanboy, and Twotop soils do not have bedrock above depths of 40 inches and Wasa soils have visible salts within depths of 8 inches of the surface. Whitewater soils have a high SAR and formed in sodium rich materials.
GEOGRAPHIC SETTING: Larvie soils are on nearly level to strongly sloping uplands and typically have convex surfaces. Slope gradients typically are 2 to 6 percent, but range from 0 to 15 percent. Larvie soils formed on the ridges in a gilgai landscape. Larvie soils formed in residuum weathered from variegated shales and mudstones. Mean annual air temperature ranges from 45 to 48 degrees F, and mean annual precipitation ranges from 12 to 18 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Conata, Hisle, Metre and Norrest soils. Conata soils have bedrock within a depth of 20 inches and are on nearby steep slopes. Hisle soils have a natric horizon and are in slightly concave areas. Metre soils are in the furrows of a gilgai landscape. They have mollic colors at depths greater than 8 inches. Norrest soils have a fine textured argillic horizon. They are on smooth ridges and sideslopes.
DRAINAGE AND PERMEABILITY: Well drained. Runoff ranges from medium to very high depending on slope. Permeability is very slow.
USE AND VEGETATION: Mostly in rangeland. Native vegetation is mainly western wheatgrass, green needlegrass, buffalograss, blue grama, sedges, and forbs.
DISTRIBUTION AND EXTENT: Inextensive, mostly in southwestern South Dakota and possibly adjacent areas in Wyoming and Nebraska.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Denver, Colorado
SERIES ESTABLISHED: Mellette County, South Dakota, 1971.
REMARKS: Diagnostic horizons and features recognized in this pedon are: Ochric epipedon - the zone from the surface of the soil to a depth of 4 inches (A horizon).