LOCATION SHULLSBURG MN+IA ILEstablished Series
TAXONOMIC CLASS: Fine, mixed, superactive, mesic Aquic Argiudolls
TYPICAL PEDON: Shullsburg silt loam on a 4 percent concave slope on a sideslope of dissected uplands in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 10 inches; black (10YR 2/1) silt loam; dark gray (10YR 4/1) dry, moderate very fine granular structure; neutral; abrupt wavy boundary. (6 to 10 inches thick)
A3--10 to 17 inches; very dark grayish brown (10YR 3/2) heavy silt loam, grayish brown (10YR 5/2) dry; moderate very fine granular structure; friable; many very fine tubular pores; slightly acid; gradual irregular boundary. (4 to 10 inches thick)
B21t--17 to 22 inches; dark grayish brown (10YR 4/2) silty clay loam, many very dark grayish brown (10YR 3/2) coatings on faces of peds; common medium distinct yellowish brown (10YR 5/4) mottles; moderate very fine subangular blocky structure; friable; few thin clay films on faces of peds; slightly acid; clear wavy boundary. (4 to 10 inches thick)
B22t--22 to 26 inches; dark brown (10YR 4/3) silty clay loam, very dark grayish brown (10YR 3/2) coatings on faces of peds; common fine faint grayish brown (10YR 5/2) mottles; moderate fine subangular blocky structure; friable; common thin clay films on faces of peds; slightly acid; clear wavy boundary. (0 to 8 inches thick)
IIB23t--26 to 31 inches; yellowish brown (10YR 5/6) clay; few soft fragments of greenish gray (5Y 5/1) shale; strong fine angular blocky structure; firm; many fine black clay films in tubular pores and on faces of peds; slightly acid; gradual wavy boundary. (2 to 10 inches thick)
IIB3t--31 to 37 inches; yellowish brown (10YR 5/4) clay; many medium prominent greenish gray (5GY 6/1) mottles; weak coarse prismatic structure; extremely firm; few fine and very fine tubular pores; common black clay films in fine pores; slightly acid; gradual wavy boundary. (0 to 10 inches thick)
IICr--37 to 60 inches; greenish gray (5GY 6/1) shale; many large prominent yellowish brown (10YR 5/4) mottles; massive with some laminations and vertical cleavages; extremely firm; slight effervescence; mildly alkaline.
TYPE LOCATION: Olmsted County, Minnesota; about 8 miles northwest of Rochester, Minnesota; 1,230 feet south and 1,000 feet east of northwest corner of sec. 3, T. 107 N., R. 15 W.
RANGE IN CHARACTERISTICS: Thickness of solum and depth to shale bedrock are 20 to 40 inches. The thickness of the loess mantle is 15 to 30 inches. The thickness of the part of the solum in residuum is 6 to 18 inches. Content of coarse fragments of shale, limestone, or sandstone ranges from 0 to 10 percent. The mollic epipedon is 10 to 18 inches thick. The average content of clay in the upper 20 inches of the argillic horizon is 35 to 50 percent.
The A horizon has 10YR hue, value of 2 or 3, and chroma of 1 or 2. Typically, it is silt loam, but silty clay loam is in the range. It has weak or moderate granular or subangular blocky structure. It is medium acid through neutral.
The part of the B horizon that formed in loess has hue of 10YR or 2.5Y, value of 4 or 5, and chroma of 2 through 4. It has lower or higher chroma mottles than the matrix in most to all parts, and it must have low chroma mottles in the upper part if the hue is 10YR and the chroma is 3 or 4, or if the hue is 2.5Y and the chroma is 4. It is heavy silt loam or silty clay loam. It has moderate subangular blocky or prismatic structure. It is friable or firm. It has few through many thin or medium clay films on faces of peds in at least some part. It is medium acid through neutral.
The IIB horizon has hue of 10YR, 2.5Y, or 5Y, value of 5 or 6, and chroma of 2 through 6. It has mottles in some to all parts. It is silty clay or clay. It has subangular blocky or prismatic structure that is moderate or strong in the upper part and weak or moderate in the lower part. It is firm through extremely firm. It has few through many thin through thick clay films. It is slightly acid through mildly alkaline.
The IICr horizon has hue of 2.5Y, 5Y, 5GY, or 5BG, value of 5 or 6, and chroma of 1 through 6. It is clay or silty clay. It is massive or has horizontal cleavage. It has thin strata of sandstone or limestone in some pedons. It has iron or manganese oxide masses or concretions in some pedons. It is neutral or mildly alkaline. It lacks or has slight effervescence.
COMPETING SERIES: These are the Denrock series in the same family and the Greenton, Kent, Loran, Schapville, and Snead series. Denrock soils lack shale bedrock beginning between depths of 20 to 40 inches and have acid sola. Greenton soils have thicker sola which is finer textured in the upper part and, in addition, lack a paralithic contact at depths of less than 40 inches. Kent soils formed in residuum weathered partly from acid shale and partly from sandstone and, in addition, have more acid sola and a higher sand content in the lower B horizon. Loran soils have a silt layer more than 30 inches thick and contain less clay in the series control section. Schapville soils formed in similar soil material, but lack low chroma mottles within a depth of 6 inches below the lower boundary of the mollic epipedon. Snead soils formed in residuum weathered from calcareous shale and have finer textures in the upper part of the solum and, in addition, lack argillic horizons.
GEOGRAPHIC SETTING: Shullsburg soils have plane or concave slopes on uplands and foot slopes of upland hills. Slope gradients typically are 1 to 3 percent but range up to 25 percent. These soils formed in silty sediments (loess) 15 to 30 inches thick and clayey residuum weathered from shale. Mean annual temperature ranges from 45 to 52 degrees F, and mean annual precipitation ranges from 28 to 35 inches. The growing season ranges from 140 to 160 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Calamine, Derinda, Haverhill, and the competing Loran and Schapville soils. Derinda soils have thinner or lighter-colored surface horizons. Loran soils have silty surface layer greater than 30 inches thick. The well and moderately well drained Schapville soils and the poorly and very poorly drained Calamine and Haverhill soils are in drainage sequence with the Shullsburg soils. Haverhill soils lack or have a thinner mantle of loess.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Runoff is slow or medium. Internal drainage is slow. Permeability is slow.
USE AND VEGETATION: Most areas are cropped to corn, small grain, and forages. Some seepage and more sloping areas are used for growing pasture. Native vegetation was mixed prairie and forest.
DISTRIBUTION AND EXTENT: Southwestern Wisconsin, northwestern Illinois, southeastern Minnesota, and possibly adjoining areas of Iowa. Shullsburg soils are of small extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Stephenson County, Illinois, 1969.
REMARKS: Color in that part of the B horizon formed in shale is due partially to the color of parent material. Responsibility for this series was transferred from Wisconsin to Minnesota in February 1977.