LOCATION IROQUOIS IN
Established Series
Rev. LCO-WDH
11/2021
IROQUOIS SERIES
The Iroquois series consist of deep, very poorly drained soils formed in loamy outwash and are underlain by clayey sediments on lake plains. Permeability is moderate in the solum and slow in the underlying material. Slopes range from 0 to 2 percent. Mean annual precipitation is about 37 inches, and mean annual temperature is about 50 degrees F.
TAXONOMIC CLASS: Fine-loamy over clayey, mixed, semiactive, mesic Typic Argiaquolls
TYPICAL PEDON: Iroquois fine sandy loam - on a slightly concave position in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 11 inches; very dark brown (10YR 2/2) fine sandy loam, dark gray (10YR 4/1) dry; moderate medium granular structure; friable; common medium roots; medium acid; abrupt smooth boundary.
A--11 to 16 inches; very dark grayish brown (10YR 3/2) fine sandy loam, dark grayish brown (10YR 4/2) dry; common medium prominent light olive brown (2.5Y 5/4) mottles; moderate medium subangular blocky structure; firm; few fine roots; thin discontinuous dark gray (10YR 4/1) and very dark gray (10YR 3/1) organic stains on faces of peds; medium acid; clear wavy boundary. (Combined thickness of the A horizons is 13 to 18 inches.)
Btg1--16 to 21 inches; dark grayish brown (2.5Y 4/2) sandy clay loam; many medium faint light olive brown (2.5Y 5/4) mottles; weak coarse prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots; thin discontinuous dark gray (10YR 4/1) clay films on faces of peds; few very dark gray (10YR 3/1) organic stains on faces of peds; 1 percent gravel; slightly acid; clear wavy boundary. (5 to 7 inches thick)
Btg2--21 to 27 inches; gray (10YR 5/1) sandy clay loam; many medium prominent light olive brown (2.5Y 5/4) mottles; weak medium prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots; thin discontinuous dark gray (10YR 4/1) clay films on faces of peds; 1 percent gravel; slightly acid; clear wavy boundary. (6 to 8 inches thick)
Btg3--27 to 31 inches; gray (5Y 6/1) clay loam; many medium prominent light olive brown (2.5Y 5/4) mottles; weak coarse prismatic structure parting to moderate medium subangular blocky; firm; thin discontinuous gray (5Y 5/1) clay films on faces of peds; neutral; clear wavy boundary. (0 to 4 inches thick)
2Cg--31 to 60 inches; gray (N 6/0) silty clay; many medium distinct light olive brown (2.5Y 5/4) mottles; massive; firm; strong effervescence; moderately alkaline.
TYPE LOCATION: Jasper County, Indiana; about 3 miles south and .5 mile west of Rensselaer; 100 feet north and 2000 feet east of the southwest corner of sec. 12, T. 28 N., R. 7 W.
RANGE IN CHARACTERISTICS: The thickness of the solum is 24 to 38 inches.
The A horizon has hue of 10YR, value of 2 or 3, and chroma of 1 or 2. It ranges from medium acid to neutral. Gravel content is less than 2 percent.
The Bt horizon has hue of 10YR, 5Y, or 2.5Y; value of 4 to 6; and chroma of 1 or 2. The Bt horizon is sandy clay loam, clay loam or sandy loam. The clay content dominantly ranges from 18 to 25 percent. In many pedons thin subhorizons up to 4 inches thick are in the lower most part of the Bt horizon and contain somewhat more clay. The Bt horizon ranges from medium acid to neutral. Gravel content is less than 2 percent.
The 2C horizon has hue of 10YR, value of 6, and chroma of 1 or 2, or is neutral and has value of 6. It is clay or silty clay and the clay content ranges from 45 to 60 percent. It is mildly alkaline or moderately alkaline.
COMPETING SERIES: There are no other series in this family.
Navan soils formed in similar material but are not contrasting.
GEOGRAPHIC SETTING: Iroquois soils are on glacial lake plains. Slopes range from 0 to 2 percent. Iroquois soils formed in 24 to 38 inches of loamy outwash and are underlain by clayey sediments. Mean annual precipitation ranges from 35 to 39 inches, and mean annual temperature ranges from 48 to 52 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Darroch,
Montgomery,
Rensselaer,
Seward, and
Strole soils. Darroch soils do not have contrasting textures and are on slightly higher lying positions in the landscape. Montgomery soils have more clay in the upper part of the solum and are on similar landscape positions. Seward soils have arenic layers, are moderately well drained, and are on higher lying landscape positions. Rensselaer soils do not have contrasting textures and are on similar lanscape positions. Strole soils have more clay in the upper part of the solum and on slightly higher lying landscape positions.
DRAINAGE AND PERMEABILITY: Very poorly drained. Surface water runoff is very slow or ponded. Permeability is moderate in the solum and slow in the underlying material.
USE AND VEGETATION: Most areas are drained and cropped to corn, soybeans, and small grain. Native vegetation was swamp grasses.
DISTRIBUTION AND EXTENT: Northwestern Indiana and possibly northeastern Illinois. They are of minor extent.
SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: AMHERST, MASSACHUSETTS
SERIES ESTABLISHED: Jasper County, Indiana, 1985.
REMARKS: Diagnostic features and horizons recognized in this pedon are: mollic epipedon - 0 to 16 inches (Ap, A); argillic horizon - 16 to 31 inches (Btg1, Btg2, Btg3).
ADDITIONAL DATA: Laboratory data is available from the Purdue Soil Characterization Laboratory (File No. JR7914).
National Cooperative Soil Survey
U.S.A.