LOCATION SHIELDS MNEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Vertic Epiaqualfs
TYPICAL PEDON: Shields silty clay loam on a plane level slope of 1 percent on a moraine at an elevation of 1,140 feet in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; cloddy; friable; few inclusions of dark gray (10YR 4/1); moderately acid; abrupt smooth boundary. (Combined thickness of the A horizon is 6 to 10 inches.)
Eg--8 to 10 inches; dark gray (10YR 4/1) silt loam, gray (10YR 6/1) dry; very dark gray (10YR 3/1), gray (10YR 5/1) dry coatings on peds; dark gray (10YR 4/1) when kneaded; weak medium platy structure; friable; moderately acid; clear wavy boundary. (0 to 6 inches thick)
B/E--10 to 14 inches; dark gray (10YR 4/1) silty clay; few fine prominent light olive brown (2.5Y 5/4) Fe concentrations; moderate fine subangular blocky structure; firm; thin continuous porous silty and sandy very dark gray (10YR 3/1), dark gray (10YR 4/1) dry and gray (10YR 5/1) dry coatings on peds; few sand size shale particles; strongly acid; clear wavy boundary. (0 to 8 inches thick)
Btg1--14 to 18 inches; dark grayish brown (2.5Y 4/2) silty clay; few fine distinct olive brown (2.5Y 4/4) Fe concentrations; strong fine subangular blocky structure; very firm; few thin patchy porous silty and sandy dark gray (10YR 4/1) coatings on peds and thin to thick continuous very dark gray (10YR 3/1) clay films on faces of peds; few sand size shale particles; strongly acid; clear wavy boundary.
Btg2--18 to 27 inches; grayish brown (2.5Y 5/2) silty clay; few fine distinct light olive brown (2.5Y 5/4) Fe concentrations; moderate medium prismatic structure parting to moderate fine and medium angular blocky structure; very firm; thick continuous black (10YR 2/1) and very dark gray (10YR 3/1) clay films on faces of peds and in old root channels; few sand size shale particles; strongly acid; clear wavy boundary.
Btg3--27 to 41 inches; gray (5Y 5/1) and olive gray (5Y 5/2) silty clay; common fine prominent olive (5Y 5/6) Fe concentrations; weak medium and coarse prismatic structure; firm; many black clayey fillings in old root channels and pores; moderately acid; clear wavy boundary. (Combined thickness of the Btg horizons is 14 to 40 inches.)
2Bk--41 to 80 inches; olive (5Y 5/3) silty clay loam; many fine prominent light olive brown (2.5Y 5/6) Fe concentrations; weak coarse prismatic structure; firm; few soft secondary limy segregations and filaments; about 5 percent gravel; strongly effervescent; moderately alkaline.
TYPE LOCATION: Steele County, Minnesota; 300 feet west and 90 feet south of the northeast corner of sec. 27, T. 108 N., R. 21 W., USGS Medford West quadrangle; lat. 44 degrees 8 minutes 17 seconds N. and long. 93 degrees 19 minutes 39 seconds W., NAD27
RANGE IN CHARACTERISTICS: Depth to free carbonates typically is 36 to 42 inches but ranges from 28 to 60 inches. Gravel of mixed lithology and commonly dominated by shale typically comprise 2 to 8 percent of the volume, but in a few pedons the upper part either lacks gravel or has less than 2 percent. Shale is the major component in the sand fraction.
The Ap or A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. The E horizon, where present, typically has hue of 10YR, value of 4 or 5, and chroma of 1 or 2. Fe concentrations are in some E horizons. The A and E horizons typically are silt loam or silty clay loam, but can be loam or clay loam. They are moderately or slightly acid.
The B/E horizon has color, textures and reaction similar to the E and Btg horizons.
The Btg horizons have hue of 2.5Y or 5Y, value of 4 or 5, and chroma of 1 or 2. Some pedons have hue of 10YR in the upper part of the Btg horizon. The Btg horizon typically is silty clay or clay, but in some pedons is silty clay loam or clay loam. The upper 20 inches of the argillic horizon typically averages between 42 and 55 percent clay with an extreme range of 40 to 60 percent and from 15 to 30 percent fine sand and coarser. Reaction ranges from moderately acid to very strongly acid.
The Bk or 2Bk horizon has hue of 2.5Y or 5Y, value of 4 or 5, and chroma of 2 or 3. It commonly has Fe concentrations and depletions. Typically it is a firm, silty clay loam, clay loam, or clay, and less commonly a friable loam or clay loam.
Some pedons have a C horizon.
COMPETING SERIES: These are the Bluford, Bucknell, Gifford, Hurst, Kernan, Kilwinning, Kniffin, Leonard, McGirk, Pershing, Rathbun, Rinda, Sabina, Sexton, Stateline and the Weir series. The Bluford, Bucknell, Gifford, Kniffin, Pershing, Rathbun, Stateline and Weir soils have free carbonates below a depth of 60 inches. The Hurst, Kernan and Kilwinning soils have less than 15 percent sand in the lower third of the series control section. Leonard, Rinda and Sexton soils lack rock fragments in the lower third of the series control section. McGirk soils average less than 5 percent sand in the particle size control section. Sabina soils have illite as the dominant clay mineralogy in the lower third of the series control section.
GEOGRAPHIC SETTING: Shields soils are on ground moraines of low relief and on nearly level hilltops within the strongly morainic areas. Slopes are plane or slightly convex and range from 0 to 3 percent. These soils formed in moderately fine and fine textured glacial till or flow till with lacustrine sediments containing appreciable amounts of shale that mantles friable, loam or clay loam till to depths ranging from 3 to 10 feet or more. These sediments are Late Wisconsinan in age. Mean annual temperature is 45 to 52 degrees F. Mean annual precipitation is approximately 28 to 32 inches. Frost-free days range from 125 to 170. Elevation above sea level ranges from 700 to 1600 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: The main ones are the Kilkenny, Lerdal, and Mazaska soils. These soils formed in materials that are similar to those of the Shields soils and are members of a drainage sequence with the Shields soils. The moderately well drained Kilkenny and the somewhat poorly drained Lerdal soils are on adjacent gently sloping to steep areas. Mazaska soils are poorly drained and are nearly level.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Surface runoff is medium. Permeability is slow. The perched seasonal high water table is at 1.5 to 2.5 feet during April to June.
USE AND VEGETATION: Mostly cultivated with corn, soybeans, and hay being the principal crops. A few areas are in pasture and forest. Native vegetation dominantly is burr oak with a understory of grasses.
DISTRIBUTION AND EXTENT: Primarily on moraines along the eastern edge of the Des Moines Lobe in southeastern Minnesota. Inextensive, but significant, because it is confined physiographical areas of 20 to 80 acres in size.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Hennepin County, Minnesota, 1969.
REMARKS: Diagnostic features recognized in this pedon are: ochric epipedon-from the soil surface to a depth of 8 inches; too thin for a mollic horizon (Ap); albic horizon- the zone from 8 to 10 inches (Eg); argillic horizon-the zone from 10 to 41 inches (B/E, Btg1, Btg2, Btg3).