LOCATION DARFUR MN+IAEstablished Series
TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Endoaquolls
TYPICAL PEDON: Darfur loam with a plane slope on a delta in a glacial lake plain in a cultivated field. (Colors are for moist conditions unless otherwise stated.)
Ap--0 to 9 inches; black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak very fine subangular blocky structure; friable; neutral; abrupt smooth boundary.
A--9 to 14 inches; very dark gray (10YR 3/1) loam, dark gray (10YR 4/1) dry; weak very fine subangular blocky structure; friable; few channels of very dark grayish brown (10YR 3/2); neutral; clear irregular boundary.
AB--14 to 19 inches; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; weak very fine subangular blocky structure; friable; few very dark gray (10YR 3/1) strata and tongues; neutral;; clear irregular boundary. (Combined thickness of A horizons is 14 to 24 inches.)
Bg1--19 to 22 inches; dark grayish brown (2.5Y 4/2) fine sandy loam; weak very fine subangular blocky structure; very friable; few dark colored concretions; many fine faint grayish brown (2.5Y 5/2) and few fine distinct dark brown (7.5YR 3/2) Fe depletions; neutral; clear wavy boundary.
Bg2--22 to 27 inches; grayish brown (2.5Y 5/2) fine sandy loam; weak very fine subangular blocky structure; very friable; few dark colored concretions; many fine faint dark grayish brown (2.5Y 4/2) and few fine distinct dark brown (7.5YR 3/2) Fe depletions; neutral; clear wavy boundary.
Bg3--27 to 31 inches; grayish brown (2.5Y 5/2) fine sandy loam; weak very fine subangular blocky structure; very friable; few dark colored concretions; many fine faint dark grayish brown (2.5Y 4/2) and light brownish gray (10YR 6/2) Fe depletions; many medium distinct pale brown (10YR 6/3) Fe concentrations; neutral; clear wavy boundary. (Combined thickness of the Bg horizons is 6 to 20 inches.)
Cg--31 to 60 inches; light olive gray (5Y 6/2) with some strata of olive gray (5Y 5/2) statified fine sand, loamy fine sand, and fine sandy loam; massive; very friable; common medium prominent brown (7.5YR 4/4) Fe concentrations mostly in lower part; few dark colored concretions; neutral.
TYPE LOCATION: Blue Earth County, Minnesota; about 2 miles northwest of Garden City; 1,400 feet west and 500 feet south of the northeast corner, sec. 21, T. 107 N., R. 28 W.
RANGE IN CHARACTERISTICS: The thickness of solum ranges from 20 to 40 inches. The depth to free carbonates ranges from 20 to 70 inches. These soils lack coarse fragments in the solum and C horizon. The 10 to 40 inch control section is fine sandy loam, very fine sandy loam, or loam averaging less than 18 percent clay and at least 85 percent of the sand fraction is fine or very fine (but the content of fine sand and coarser exceeds 15 percent). The mollic epipedon is 14 to 24 inches thick.
The A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It is typically fine sandy loam, very fine sandy loam, loam, or sandy clay loam; but in some pedons is sandy loam or coarse sandy loam. It is neutral or slightly acid.
The Bg horizon has a matrix with hue of 2.5Y or 5Y, value of 4 or 5, and chroma of 1 or 2. It has mottles in all parts. It is mostly fine sandy loam, sandy loam, loam, or sandy clay loam. However, stratification of these commonly is in many pedons. In addition, subhorizons with texture of loamy sand, loamy fine sand, loamy very fine sand, very fine sandy loam, and silt loam are in this horizon in some pedons. It is neutral or mildly alkaline.
The C horizon has a matrix with hue of 2.5Y or 5Y, value of 5 or 6, and chroma of 1 or 2. It has mottles at least in some part. Dominant textures are fine sand, loamy fine sand, and fine sandy loam, but includes sand, loamy sand and sandy loam. These textures typically are stratified. Also, finer textured layers are in this horizon in some pedons. It ranges from neutral through moderately alkaline. In some pedons a 2C horizon of loam or clay loam glacial till or silty loam or silty clay loam lacustrine sediments begins at depths as shallow as 50 inches.
COMPETING SERIES: These are the Corunna, Dassel, Gilford, Hanska, Jubilee, Lyles, Toolesboro, and Zadoc series in the same family. The Corunna soils have continuous, fine-loamy, 2C horizons beginning at depths ranging from 25 to 40 inches. The Dassel soils are in depressions. The Gilford and Hanska soils contain less fine and very fine sand in the solum and C horizon and lack the loamy strata. In addition, Gilford soils have a warmer more humid climate. The Jubilee soils have few to many mica flakes in the profile and formed in nonglacial sediments. The Lyles soils have less than 85 percent of the sand fraction in the fine and very fine and has up to 10 percent fine gravel. Toolesboro soils have redder hue and higher chroma in much of the Bg horizon and a lower proportion of fine and very fine sand. Zadoc soils have an accumulation of iron oxides in the solum.
GEOGRAPHIC SETTING: These soils have plane slopes with gradient of less than 2 percent. They commonly are on the deltaic portions of glacial lake plains and less commmonly on outwash plains, and stream terraces. They formed in loamy and sandy lacustrine or outwash sediments that are dominated by fine and very fine sand and that commonly are stratified. Loamy glacial till or silty lacustrine sediments underlie these sediments at depths below 50 inches in some pedons. These sediments are of the Des Moines lobe of the Late Wisconsinan glaciation. Mean annual precipitation is 26 to 30 inches, and mean annual temperature is 45 to 48 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dassel, Fieldon, and Grogan soils which formed in similar sediments and are members of a hydrosequence with Darfur soils. The very poorly drained Dassel soils are in depressions and swales. The poorly drained Fieldon soils have carbonates throughout and are on terrain that is similar to that of the Darfur soils. The moderately well drained Grogan soils are on slight rises. The moderately well and somewhat poorly drained sandy Litchfield soils and the somewhat excessively drained sandy Lasa soils are associated in some places.
DRAINAGE AND PERMEABILITY: Poorly drained. Surface runoff is negligible to low. Permeability is moderate or moderately rapid in the upper mantle and moderately rapid in the subsoil and underlying material.
USE AND VEGETATION: Mostly cropped to corn and soybeans. Native vegetation was a wet-site community of the tall grass prairie.
DISTRIBUTION AND EXTENT: Southern Minnesota and northern Iowa. Moderately extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Blue Earth County, Minnesota, 1975.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 19 inches (Ap, A, and AB horizons); Cambic horizon - zone from 19 to 31 inches (Bg1, Bg2, and Bg3 horizons).
Classification only was changed 5/94. Competing series and other updates will be made later.
ADDITIONAL DATA: Refer to MAES Central File Code No. 976 for results of laboratory analysis of a representative pedon on this series.