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soil clod

Darmstadt

soil profile

DARMSTADT SERIES

LOCATION                IL

Established Series
Rev. DEW-JBF-ZWW
07/2018


The Darmstadt series consists of very deep, somewhat poorly drained soils formed in loess or in loess and the underlying silty pedisediment on till plains. These soils contain a concentration of exchangeable sodium in the subsoil. Slope ranges from 0 to 10 percent. Mean annual temperature is about 13 degrees C (55 degrees F), and mean annual precipitation is about 965 millimeters (38 inches).

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Aquic Natrudalfs

TYPICAL PEDON: Darmstadt silt loam, on a nearly level summit in a cultivated field at an elevation of about 143 meters (470 feet) above mean sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 20 centimeters (0 to 8 inches); dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; weak thick platy structure parting to weak very fine granular; friable; many very fine roots; few fine continuous tubular pores; few fine rounded black (10YR 2/1) iron-manganese nodules with sharp boundaries throughout; 1 percent exchangeable sodium; neutral; abrupt smooth boundary. [13 to 23 centimeters (5 to 9 inches) thick]

E--20 to 28 centimeters (8 to 11 inches); light brownish gray (10YR 6/2) and grayish brown (10YR 5/2) silt loam, light gray (10YR 7/2) dry; weak thick platy structure parting to weak fine subangular blocky; friable; common very fine roots; few fine constricted tubular pores; many fine and medium rounded black (10YR 2/1) iron-manganese nodules with sharp boundaries throughout; 4 percent exchangeable sodium; neutral; abrupt smooth boundary. [8 to 25 centimeters (3 to 10 inches) thick]

Btn1--28 to 41 centimeters (11 to 16 inches); brown (10YR 5/3) silty clay loam; weak medium prismatic structure parting to moderate fine and medium angular blocky; firm; many very fine roots; few faint grayish brown (10YR 5/2) clay films on faces of peds; common medium faint grayish brown (10YR 5/2) iron depletions in the matrix; common medium prominent yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; few fine irregular strong brown (7.5YR 5/6) iron-manganese masses and few medium rounded black (7.5YR 2.5/1) iron-manganese nodules with clear strong brown (7.5YR 4/6) boundaries; 7 percent exchangeable sodium; very strongly acid; gradual smooth boundary.

Btn2--41 to 53 centimeters (16 to 21 inches); pale brown (10YR 6/3) silty clay loam; moderate medium prismatic structure parting to strong medium angular blocky; firm; common very fine roots; common distinct gray (10YR 5/1) clay films on faces of peds; many fine faint grayish brown (10YR 5/2) iron depletions in the matrix; many fine distinct brownish yellow (10YR 6/6) and many fine prominent yellowish brown (10YR 5/8) masses of oxidized iron in the matrix; few fine irregular strong brown (7.5YR 5/6) iron-manganese masses and few medium rounded black (7.5YR 2.5/1) iron-manganese nodules with clear boundaries and strong brown (7.5YR 4/6) surfaces throughout; 12 percent exchangeable sodium; moderately acid; gradual smooth boundary.

Btn3--53 to 69 centimeters (21 to 27 inches); pale brown (10YR 6/3) and light brownish gray (10YR 6/2) silty clay loam; moderate coarse prismatic structure; firm; few very fine roots; few distinct gray (10YR 5/1) clay films on faces of peds; many coarse prominent strong brown (7.5YR 5/8) masses of oxidized iron in the matrix; few medium irregular very dark brown (7.5YR 2.5/2) iron-manganese masses with diffuse boundaries and strong brown (7.5YR 5/6) surfaces throughout; 17 percent exchangeable sodium; slightly acid; gradual smooth boundary.

Btng1--69 to 89 centimeters (27 to 35 inches); light brownish gray (10YR 6/2) silty clay loam; weak coarse prismatic structure; firm; few very fine roots; common fine vesicular pores; few distinct gray (10YR 5/1) clay films on vertical faces of peds; few distinct black (10YR 2/1) and very dark gray (10YR 3/1) organo-clay films lining root channels and pores; few medium faint dark gray (10YR 4/1) iron depletions in the matrix; few medium distinct dark yellowish brown (10YR 4/4) and light yellowish brown (10YR 6/4) masses of oxidized iron in the matrix; common coarse irregular black (7.5YR 2.5/1) iron-manganese masses with diffuse strong brown (7.5YR 4/6) boundaries; 20 percent exchangeable sodium; neutral; clear smooth boundary.

Btng2--89 to 99 centimeters (35 to 39 inches); light gray (10YR 7/1) silty clay loam; weak coarse prismatic structure; friable; few very fine roots; few very fine vesicular pores; few distinct gray (10YR 5/1) clay films on vertical faces of peds; few coarse prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; few medium irregular black (7.5YR 2.5/1) and common coarse irregular strong brown (7.5YR 5/6) iron-manganese masses in the matrix; 25 percent exchangeable sodium; slightly alkaline; abrupt smooth boundary. [Combined thickness of the Bt horizon is 46 to 102 centimeters (18 to 40 inches).]

Cng1--99 to 112 centimeters (39 to 44 inches); light gray (10YR 7/1) silt loam; massive; friable; few very fine roots; few very fine vesicular pores; many coarse prominent yellowish brown (10YR 5/6 and 10YR 5/8), and strong brown (7.5YR 5/6) masses of oxidized iron in the matrix; common medium and coarse irregular black (7.5YR 2.5/1) and strong brown (7.5YR 5/6) iron-manganese masses; few medium irregular white (10YR 8/1) carbonate nodules throughout; 25 percent exchangeable sodium; slightly effervescent; slightly alkaline; abrupt smooth boundary.

Cng2--112 to 158 centimeters (44 to 62 inches); light gray (10YR 7/1) silt loam; massive; friable; few fine tubular and vesicular pores; few distinct very dark grayish brown (10YR 3/2) clay films lining root channels and pores; many coarse prominent yellowish brown (10YR 5/6 and 10YR 5/8) masses of oxidized iron in the matrix; few medium irregular black (7.5YR 2.5/1) and medium and coarse irregular strong brown (7.5YR 5/6) iron-manganese masses; about 25 percent exchangeable sodium; slightly effervescent; moderately alkaline; gradual smooth boundary.

Cg--158 to 200 centimeters (62 to 79 inches); light gray (10YR 7/1) silt loam; massive; friable; few distinct very dark grayish brown (10YR 3/2) organo-clay films lining root channels; many coarse prominent yellowish brown (10YR 5/6) masses of oxidized iron in the matrix; few fine irregular black (7.5YR 2.5/1) and common medium irregular strong brown (7.5YR 5/6) iron-manganese masses; moderately alkaline.

TYPE LOCATION: St. Clair County, Illinois; about 2 miles south of Smithton; 1,202 feet west and 84 feet south of the northeast corner of sec. 9, T. 2 S., R. 8 W.; USGS Freeburg, IL topographic quadrangle; lat. 38 degrees, 22 minutes, 52 seconds North and long. 89 degrees, 59 minutes, 7 seconds West, NAD 27; Std Latitude 38.3808698 decimal degrees and Std Longitude -89.9850772 decimal degrees, WGS84.

RANGE IN CHARACTERISTICS:
Depth to the base of the natric horizon: typically 89 to 127 centimeters (35 to 50 inches) but ranges from 76 to 152 centimeters (30 to 60 inches)
Thickness of the loess: typically greater than 152 centimeters (60 inches) but is as thin as 114 centimeters (45 inches) in some pedons
Particle-size control section: averages between 27 and 35 percent clay and less than 10 percent sand
Other features: carbonates commonly are in the natric horizon, but are not everywhere present

Ap horizon:
Hue: 10YR
Value: 3 to 5 (5 or 6 dry)
Chroma: 2 or 3
Texture: silt loam but severely eroded pedons may be silt loam or silty clay loam
Clay content: averages 18 to 27 percent but ranges from 12 to 35 percent
Sand content: averages than 7 percent
Reaction: strongly acid to neutral but includes very strongly acid in severely eroded pedons

E horizon:
Hue: 10YR
Value: 5 or 6
Chroma: 2
Clay content: 12 to 27 percent
Sand content: averages than 7 percent
Reaction: strongly acid to neutral

In some eroded areas the E horizon has been mixed with the Ap horizon.

Btn and Btng horizons:
Hue: 10YR or 2.5Y
Value: 4 to 7
Chroma: 1 to 6; typically has chroma of 3 or higher in the upper part and becomes gleyed in the lower part
Texture: dominantly silty clay loam but may have thin subhorizons of silty clay and grades to silt loam in the lower part in some pedons
Clay content: averages 27 to 35 percent in the upper part but ranges to a maximum of 42 percent in thin subhorizons, and averages 20 to 35 percent in the lower part
Sand content: averages than 7 percent
Reaction: very strongly acid to slightly alkaline in the upper part, and neutral to strongly alkaline in the lower part

Some pedons have a Bg, BC, 2Bt, 2Bg, or 2BC horizon in the lower part of the solum.

Cng or Cg horizon; 2Cng or 2Cg horizon below depth of 114 cm:
Hue: 10YR to 5Y
Value: 5 to 7
Chroma: 1 or 2
Texture: silt loam or silty clay loam in the Cng or Cg horizon, but ranges to loam or clay loam in the 2Cng or 2Cg horizon
Reaction: slightly alkaline to strongly alkaline; some pedons contain carbonates
Clay content: 15 to 30 percent
Sand content: averages less than 7 percent in the Cng or Cg horizon; 10 to 25 percent in the 2Cng or 2Cg horizon
Rock fragment content: 0 to 5 percent

COMPETING SERIES: There are no other series in this family.

GEOGRAPHIC SETTING: Darmstadt soils are on interfluves, convex summits, and in upland drainageways on till plains. Slope ranges from 0 to 10 percent. These soils contain a concentration of exchangeable sodium in the subsoil. These soils typically formed in loess, or in loess and the underlying silty pedisediment. The material beneath the loess is Illinoian-age till or the silty erosional sediments that lie above the till and contains a component of sand. The loess is late Wisconsinan-age Peoria Loess and the underlying silty material is early Wisconsinan-age Roxana Silt. The till commonly contains a strongly developed paleosol. Mean annual temperature ranges from 12 to 14 degrees C (53 to 57 degrees F). Mean annual precipitation ranges from 914 to 1067 millimeters (36 to 42 inches). Frost-free period is 175 to 200 days. Elevation is 122 to 229 meters (400 to 750 feet) above mean sea level.

GEOGRAPHICALLY ASSOCIATED SOILS: 

These are the CisneCowdenCoultervilleGrantforkHerrickHoyletonHueyOconeePiasa, and Tamalco soils. The poorly drained Cisne, Cowden, Huey, and Piasa soils are on broad, nearly level interfluves. Cisne and Cowden soils are in fine-textured families and do not have a natric horizon. The somewhat poorly drained Coulterville soils contain a concentration of exchangeable sodium in the subsoil, but do not have a natric horizon, and are on similar landforms nearby. The somewhat poorly drained Grantfork soils contain a concentration of exchangeable sodium in the subsoil and are on side slopes below the Darmstadt soils. The somewhat poorly drained Herrick, Hoyleton, and Oconee soils are in fine-textured families and do not have a natric horizon. Hoyleton and Oconee soils are in a complex pattern with Darmstadt soils on the landscape in most places. The moderately well drained Tamalco soils are in a fine-textured family, have a natric horizon, and are on positions slightly higher on the landform.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Somewhat poorly drained. Saturated hydraulic conductivity is low. Permeability is very slow. The potential for surface runoff is negligible to very high. In drained areas, depth to the top of an intermittent perched high water table ranges from 15 to 61 centimeters (0.5 foot to 2.0 feet) from December to April in normal years.

USE AND VEGETATION: Most areas of Darmstadt soils are used for cultivated crops such as corn, small grains, and soybeans. Native vegetation is mixed hardwood forest or prairie grasses.

DISTRIBUTION AND EXTENT: MLRAs 113 and 114 in southern Illinois. The type location is in MLRA 114. The series is of moderate extent.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana.

SERIES ESTABLISHED: St. Clair County, Illinois, 1975.

REMARKS: Diagnostic horizons and features in this pedon include:
Ochric epipedon: from the surface to a depth of 28 centimeters (11 inches) (Ap and E horizons).
Albic horizon: from a depth of 20 to 28 centimeters (8 to 11 inches) (E horizon).
Natric horizon: from a depth of approximately 28 to 91 centimeters (11 to 39 inches) (Btn1, Btn2, Btn3, Btng1, and Btng2 horizons); Btn3, Btng1, and Btng2 horizons between depth of 53 and 91 centimeters (21 and 39 inches) contain more than 15 percent exchangeable sodium (ESP).
Aquic conditions: periodic saturation and reduction indicated by redoximorphic features throughout the soil.

Classification changed from Albic Natraqualfs to Aquic Natrudalfs with the 11/2004 revision.

ADDITIONAL DATA: Characterization data is available for the typical pedon (Pedon ID: 1973IL163001) from the Kellogg Soil Survey Laboratory, Lincoln, NE.
 


National Cooperative Soil Survey
U.S.A.