LOCATION CAVOUR SD+NDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, frigid Calcic Natrudolls
TYPICAL PEDON: Cavour loam - on a nearly level glacial till plain under grassland. When described the soil was slightly moist to 38 inches and moist below. (Colors are for dry soil unless otherwise stated.)
A--0 to 6 inches; very dark gray (10YR 3/1) loam, black (10YR 2/1) moist; moderate fine and medium granular structure; slightly hard, friable; neutral; abrupt smooth boundary. (4 to 10 inches thick)
E--6 to 8 inches; gray (10YR 5/1 and 10YR 6/1) silt loam, dark gray (10YR 4/1) and very dark gray (10YR 3/1) moist; weak thin platy structure; slightly hard, very friable; neutral; abrupt wavy boundary. (0 to 4 inches thick)
Btn1--8 to 13 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; moderate coarse columnar structure parting to strong medium and fine blocky; extremely hard, very firm, sticky and plastic; thin light gray (10YR 6/1) caps about 1/4 inch thick on tops of columns; neutral; gradual irregular boundary.
Btn2--13 to 19 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; weak medium and fine prismatic structure parting to strong medium and fine blocky; extremely hard, firm, sticky and plastic; moderately alkaline; clear wavy boundary.
Btnyz--19 to 24 inches; dark gray (5Y 4/1) clay, very dark grayish brown (2.5Y 3/2) moist; moderate fine and medium blocky structure; very hard, firm, sticky and plastic; common fine and medium accumulations of gypsum and other salts; moderately alkaline; gradual wavy boundary. (Combined thickness of Btn horizons is 9 to 24 inches.)
Byz--24 to 32 inches; grayish brown (2.5Y 5/2) clay loam, dark grayish brown (2.5Y 4/2) moist; moderate medium and coarse subangular blocky structure; very hard, firm, sticky and plastic; common fine and medium accumulations of gypsum and other salts; slight effervescence; moderately alkaline; gradual wavy boundary. (0 to 20 inches thick)
C1--32 to 43 inches; light brownish gray (2.5Y 6/2) clay loam, olive brown (2.5Y 4/4) moist; common fine distinct of gray (2.5Y 5/1) redox depletions and prominent yellowish brown (10YR 5/6) redox concentrations; massive; hard, firm, sticky and plastic; few to common fine and medium accumulations of gypsum and other salts; strong effervescence; moderately alkaline; gradual wavy boundary. (0 to 16 inches thick)
C2--43 to 60 inches; light brownish gray (2.5Y 6/2) clay loam, olive brown (2.5Y 4/4) moist; common fine prominent yellowish red (5YR 5/8) and strong brown (7.5YR 5/6) redox concentrations and common medium distinct gray (5Y 5/1) redox depletions; massive; hard, firm, sticky and plastic; few to common fine and medium accumulations of gypsum and other salts; strong effervescence; slightly alkaline.
TYPE LOCATION: Roberts County, South Dakota; about 3 miles south of Wilmot; 162 feet east and 51 feet north of the southwest corner of sec. 19, T. 122 N., R. 49 W.
RANGE IN CHARACTERISTICS: Depth to carbonates ranges from 14 to 35 inches. Depth to accumulations of gypsum and other salts ranges from 16 to 45 inches. Thickness of the mollic epipedon typically is over 16 inches but ranges from 7 to 35 inches. The natric horizon has an estimated SAR or ESP of 10 to 20.
The A horizon has hue of 10YR or is neutral, value of 3 to 5 and 2 or 3 moist. It typically is loam or silt loam, but is clay loam in some pedons. Some pedons have up to 25 percent stones on the surface. It ranges from slightly acid to slightly alkaline.
The E horizon has value of 3 to 7 and 2 to 5 moist, and chroma of 1 or 2. It is silt loam or loam, but is fine sandy loam in some pedons. It ranges from slightly acid to slightly alkaline. When cultivated, the A and E horizons become mixed.
The Btn and Btnyz horizons have hue of 10YR, 2.5Y, or 5Y; value of 3 to 5 and 2 to 4 moist; and chroma of 3 or less. They are clay loam, clay, silty clay, or silty clay loam averaging between 35 to 50 percent clay with more than 15 percent fine sand or coarser. Reaction ranges from neutral to strongly alkaline. Accumulations of gypsum and other salts are not present in the lower part of this horizon in some pedons.
The Byz horizon has hue of 10YR, 2.5Y, or 5Y; value of 5 or 6 and 4 or 5 moist; and chroma of 1 to 3. It is loam, clay loam, silty clay loam, silty clay, or clay and ranges from slightly alkaline to strongly alkaline. Some pedons do not have gypsum accumulations.
Some pedons have a Bk horizon. It is loam, clay loam, silty clay loam, silty clay or clay. Some Bk horizons have accumulations of gypsum and other salts.
The C horizon has hue of 2.5Y or 5Y, value of 5 to 7 and 4 or 5 moist, and chroma of 1 to 4. It is loam or clay loam and ranges from slightly alkaline to strongly alkaline. Accumulations of gypsum and other salts are few to common in the C horizon.
COMPETING SERIES: These are the Nahon and Rich series. Nahon soils are varved within depths of 40 inches and typically contain more silt and very fine sand. Rich soils typically do not have E horizons and have a drier soil moisture control section.
GEOGRAPHIC SETTING: The Cavour soils are on uplands having plane and slightly convex slopes. Slope gradients typically are 0 to 3 percent but range from 0 to 6 percent. Cavour soils formed in firm loam and clay loam glacial till. The mean annual air temperature ranges from 38 to 48 degrees F, and the mean annual precipitation ranges from 16 to 24 inches. Growing season is about 120 to 130 days; average growing season precipitation ranges from 14 to 18 inches; and growing degree days are about 2500 to 2800.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Aastad, Cresbard, Forman, Miranda, Parnell, Peever, and Tonka soils. Cresbard and Miranda soils are on similar positions on the landscape. Aastad, Forman, Parnell, Peever, and Tonka soils do not have natric horizons. In addition, Aastad soils are in swales. Forman soils are on higher positions on the landscape. Peever soils are on similar nearby level landscapes and on slight rises. Parnell and Tonka soils are very poorly and poorly drained and are in closed depressions.
DRAINAGE AND PERMEABILITY: Moderately well and well drained. Runoff is low to very high. Permeability is slow or very slow.
USE AND VEGETATION: These soils are used for growing small grains, corn, feed grains, and alfalfa. Native vegetation mainly is western wheatgrass, green needlegrass, blue grama, buffalograss, sedges, and forbs.
DISTRIBUTION AND EXTENT: Northeastern South Dakota and eastern North Dakota. The series is of moderate extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Beadle County, South Dakota, 1943.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of about 24 inches (A, E, Btn1, Btn2, Btnyz horizons); Natric horizon - the zone from about 8 to 24 inches (Btn1, Btn2, Btnyz horizons).