LOCATION FARMSWORTH SDEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Natrustolls
TYPICAL PEDON: Farmsworth loam - with a plane slope of 1 percent in native grass. When described the soil was dry to 35 inches. (Colors are for dry soil unless otherwise stated.)
A--0 to 4 inches; dark gray (10YR 4/1) loam, black (10YR 2/1) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; slightly acid; clear smooth boundary. (3 to 8 inches thick)
E--4 to 6 inches; gray (10YR 5/1) clay loam, very dark gray (10YR 3/1) moist; weak fine granular structure; slightly hard, friable, slightly sticky and slightly plastic; many fine roots; slightly acid; clear smooth boundary. (2 to 4 inches thick)
Btn1--6 to 9 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; moderate medium columnar structure parting to moderate medium blocky; very hard, very firm, sticky and plastic; few fine continuous clay films on faces of peds; thin discontinuous coatings of gray (10YR 5/1) on tops of columnar peds; common fine roots; slightly acid; clear smooth boundary.
Btn2--9 to 13 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; moderate medium prismatic structure parting to strong medium and fine blocky and subangular blocky; very hard, very firm, sticky and plastic; few fine clay films on vertical faces of peds; few fine roots; neutral; clear smooth boundary.
Btn3--13 to 22 inches; dark gray (10YR 4/1) clay, black (10YR 2/1) moist; moderate coarse prismatic structure parting to strong medium and fine blocky and subangular blocky; very hard, very firm, sticky and plastic; few fine clay films on vertical faces of peds; few fine roots; slight effervescence; slightly alkaline; clear wavy boundary. (Combined Btn horizons is 10 to 20 inches thick.)
Bkz1--22 to 28 inches; gray (10YR 5/1) clay, very dark gray (10YR 3/1) moist; few fine prominent olive brown (2.5Y 4/4) redox concentrations; weak coarse prismatic structure parting to moderate medium subangular blocky; hard, very firm, sticky and plastic; common fine and medium nests of gypsum; common fine and medium accumulations of carbonate; strong effervescence; slightly alkaline; gradual wavy boundary.
Bkz2--28 to 53 inches; grayish brown (2.5Y 5/2) clay, dark grayish brown (2.5Y 4/2) moist; common fine distinct very dark gray (10YR 3/1) redox depletions; common fine distinct olive brown (2.5Y 4/4) redox concentrations; weak coarse subangular blocky structure parting to weak medium subangular blocky; hard, very firm, sticky and plastic; common fine and medium nests of gypsum; common fine and medium accumulations of carbonate; strong effervescence; slightly alkaline; gradual wavy boundary. (Combined Bkz horizons is 17 to 40 inches thick.)
Cg--53 to 60 inches; gray (5Y 6/1) and light brownish gray (2.5Y 6/2) sandy clay loam, grayish brown (2.5Y 5/2) and olive gray (5Y 4/2) moist; common medium distinct pale olive (5Y 6/4) redox concentrations; massive; very hard, firm, sticky and plastic; thin lens of fine sand at depths of about 58 inches; few fine dark concretions (iron and manganese oxides); common medium accumulations of carbonate; strong effervescence; moderately alkaline.
TYPE LOCATION: Sanborn County, South Dakota; about 5 miles north of Woonsocket; 129 feet west and 120 feet north of the southeast corner, sec. 28, T. 108 N., R. 62 W.
RANGE IN CHARACTERISTICS: Thickness of the mollic epipedon ranges from 20 to 60 inches and typically includes all of the Btn horizon. Depth to carbonates ranges from 10 to 40 inches.
The A horizon has value of 3 or 4 and 2 or 3 moist. It is loam, clay loam, silt loam, or silty clay loam and ranges from medium acid to neutral.
The E horizon has value of 5 to 7 and 3 to 5 moist, and chroma of 1 or 2. It is loam, clay loam, silt loam, or silty clay loam and is medium acid or slightly acid.
The Btn horizon has hue of 10YR or 2.5Y, value of 3 to 5 and 2 to 4 moist, and chroma of 1 or 2. Typically, the column tops are evident and are hard and durable when dry. Typically, the Btn horizon is clay or silty clay averaging between 35 and 60 percent clay and less than 15 percent fine sand or coarser. It is clay loam or silty clay loam in some pedons. It has few or common, faint mottles in the lower part of some pedons. It ranges from slightly acid in the upper part to moderately alkaline in the lower part. Some pedons have accumulations of salts in the lower part as a Btnz horizon.
The Bkz horizon has hue of 10YR or 2.5Y, value of 4 to 6 and 3 to 5 moist, and chroma of 1 to 3. It is clay, clay loam, silty clay loam, or silty clay and ranges from slightly alkaline to strongly alkaline. Some pedons have Bk, Bz, or BC horizons. Some pedons do not have accumulations of gypsum or other salts in the Bk or BC horizons.
The C horizon has hue of 2.5Y or 5Y, value of 5 to 7 and 3 to 5 moist, and chroma of 1 to 4. Typically, it is clay or silty clay but range from clay loam to sandy clay loam in the lower part of some pedons. It is slightly alkaline to strongly alkaline. Strata of coarser textures are between depths of 40 and 60 inches in some pedons. Some pedons have buried horizons below a depth of 30 inches. The Bkz and C horizons have few to many, fine to coarse accumulations of carbonate and nests of gypsum. They have few to many, fine to coarse faint to distinct mottles.
COMPETING SERIES: These are the Cavo, DeGrey, Dudley, Dwight, Mosher, and Wood River series. Cavo, Dudley, Mosher, and Wood River soils contain more than 15 percent fine sand or coarser. In addition, Cavo, DeGrey, Mosher, and Wood River soils have mollic epipedons less than 20 inches thick. DeGrey soils do not have mottles in the underlying material due to wetness. Dwight soils have air warmer soil temperature control sections and mean annual temperature greater than 50 degrees F.
GEOGRAPHIC SETTING: Farmsworth soils are on broad, low lying flats in glacial outwash plains. Slope gradients are less than 2 percent. Surfaces are plane to slightly concave and have micro-relief with differences in elevation of 2 feet or less. The soils formed in clayey glaciolacustrine and alluvial sediments. Mean annual air temperature ranges from 45 to 48 degrees F, and mean annual precipitation ranges from 17 to 21 inches. Growing season is about 130 to 155 days; growing season precipitation is 13 to 17 inches; and growing degree days are about 2800 to 3200.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Artesian, Blendon, Durrstein, Enet, Fedora, Hand, Northville, Whitelake, and Woonsocket soils. Artesian soils are in similar or slightly higher positions and do not have natric horizon. Blendon, Enet, Fedora, Hand, and Woonsocket soils do not have a natric horizon and all except Fedora are in higher positions on the landscape. Fedora soils are in similar or slightly lower positions. Durrstein soils have a wetter soil moisture control section and are in lower positions on the landscape. Northville soils do not have columnar structure and are on similar landscapes. Whitelake soils are fine-loamy and are in similar or slightly higher positions on the landscape.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained or moderately well drained. Runoff is low. Permeability is slow or very slow. A temporary water table is at depths of 1.5 to 5 feet in most years.
USE AND VEGETATION: The soils are in native grass or are cropped to alfalfa and small grain. Native vegetation is mainly western wheatgrass with lesser amounts of blue grama, green needlegrass, buffalograss, sedges, and forbs.
DISTRIBUTION AND EXTENT: East-central South Dakota. The series is inextensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Sanborn County, South Dakota, November, 1978.
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 28 inches (A, E, Btn1, Btn2, Btn3, and Bkz1 horizons); natric horizon - the zone from about 6 to 22 inches (Btn1, Btn2, and Btn3 horizons).