LOCATION INTON IAEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Oxyaquic Hapludalfs
TYPICAL PEDON: Inton silt loam - on a convex slope of 6 percent - cultivated. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; brown (10YR 4/3) silt loam, pale brown (10YR 6/3) dry; about 40 percent mixing of dark yellowish brown (10YR 4/4); light yellowish brown (10YR 6/4) dry; weak very fine granular structure; friable; common fine roots; moderately acid; abrupt smooth boundary. (6 to 9 inches thick)
Bt1--8 to 14 inches; yellowish brown (10YR 5/4) silty clay loam; moderate fine angular blocky structure; firm; common fine roots; few distinct clay films on faces of peds; common distinct brown (10YR 4/3) coatings on faces of peds; common distinct very pale brown (10YR 7/3) dry silt coatings on faces of peds; common fine faint yellowish brown (10YR 5/6) and few fine distinct strong brown (7.5YR 5/6) redox concentrations; strongly acid; clear smooth boundary.
Bt2--14 to 23 inches; grayish brown (2.5Y 5/2) and yellowish brown (10YR 5/4) silty clay loam; moderate medium angular blocky structure; firm; common fine roots; common distinct clay films on faces of peds; few distinct very pale brown (10YR 7/3) dry silt coatings on faces of peds; few fine prominent brown (7.5YR 4/4) and strong brown (7.5YR 5/6) redox concentrations; few fine dark grayish brown (10YR 3/2) manganese oxides; few distinct yellowish brown (10YR 5/4) fills in old root channels; strongly acid; clear smooth boundary.
Bt3--23 to 30 inches; light brownish gray (2.5Y 6/2) silty clay loam; grayish brown (2.5Y 5/2) coatings on faces of peds; moderate medium angular blocky structure; firm; common fine roots; common distinct clay films on faces of peds; many distinct very pale brown (10YR 7/3) dry silt coatings on faces of peds; common fine prominent brown (7.5YR 4/4) and strong brown (7.5YR 5/6) redox concentrations; few fine dark oxides; strongly acid; clear smooth boundary.
Bt4--30 to 35 inches; light brownish gray (2.5Y 6/2) silty clay loam; gray (5Y 5/1) coatings on faces of some peds; weak fine and medium subangular blocky structure; friable; few fine roots; few faint clay films on faces of peds; common fine prominent yellowish brown (10YR 5/4) and strong brown (7.5YR 5/6) redox concentrations; few fine dark oxides; strongly acid; clear smooth boundary. (Combined thickness of the Bt horizons is 22 to 38 inches.)
BC--35 to 39 inches; light olive gray (5Y 6/2) silty clay loam; weak medium subangular blocky structure; friable; few fine roots; very few faint clay films on faces of peds; common fine prominent strong brown (7.5YR 5/6) and a few fine prominent yellowish red (5YR 5/8) redox concentrations; few fine dark oxides; strongly acid; clear smooth boundary. (0 to 10 inches thick)
C1--39 to 54 inches; light olive gray (5Y 6/2) silty clay loam; massive; friable; few fine roots and pores; common medium prominent strong brown (7.5YR 5/6) and common medium prominent yellowish red (5YR 4/8) redox concentrations; strongly acid; gradual smooth boundary. (10 to 18 inches thick)
C2--54 to 60 inches; light olive gray (5Y 6/2) silt loam; massive; friable; few fine roots and pores; common medium and coarse prominent strong brown (7.5YR 5/6) and common medium prominent yellowish red (5YR 4/8) redox concentrations; moderately acid.
TYPE LOCATION: Des Moines County, Iowa; about 5 miles north of Burlington; 2,325 feet east and 995 feet south of the northwest corner of sec. 28, T. 71 N., R. 2 W. U.S.G.S. Kingston, Iowa - Iowa-Illinois Topographic Quadrangle; latitude 40 degrees, 55 minutes, and 30 seconds N., longitude 91 degrees, 5 minutes, and 42 seconds W.
RANGE IN CHARACTERISTICS: The solum ranges in thickness from 30 to greater than 80 inches and lacks free carbonates. Depth to gray redox depletions typically ranges from 12 to 20 inches. The Inton soils have a matrix with a hue of 2.5Y or 5Y and chroma of 2 or less within 30 inches of the surface. Sand content is less than 5 percent in the upper 48 inches. These soils are moderately acid or strongly acid in the most acid part of the solum. Thickness of the A horizon, depth to clay maximum, maximum percent clay, thickness of the Bt horizon and depth to gray colors decreases with increasing slope gradient on convex slopes. Depth to the clay maximum ranges from about 13 to 25 inches, but it may be less in areas of significant erosion.
The Ap horizon has hue of 10YR, value of 4 and chroma of 2 or 3. It typically is silt loam or silty clay loam. The A horizon, where present, has 10YR hue, value of 3 and chroma of 1 or 2. It is 1 to 5 inches thick and is silt loam.
The E horizon commonly is present below the A horizon in areas not cultivated. It has 10YR hue, value of 4 or 5 and chroma of 2 or 3. It typically is 2 to 8 inches thick and is silt loam.
The upper part of the Bt horizon has 10YR hue, value of 4 or 5, and chroma of 3 or 4. The rest of the Bt horizons and the BC horizon have redox depletions and have matrix colors of 2.5Y or 5Y hue, value of 4 to 6, and chroma of 2 or less. The Bt horizon averages about 32 to 35 percent clay with a maximum of about 38 percent in any subhorizon. The BC horizon averages about 27 to 32 percent clay.
The C horizon has colors similar to the lower part of the Bt and the BC horizon.
In many areas, especially on the lower parts of the landscape 2Ab and 2Btgb horizons are present. Colors are variable but typically are grayish with redox concentrations present. Textures are also variable but increases in clay and sand content are evident.
COMPETING SERIES: These are the Barony (T), Birkbeck, Downsouth (T), Elco, Grays, Herdick, Homen (T), Iona, Kaneville (T), Libre, Mayville, Redbud, Rocheport (T), Somonank (T), Windere, Winfield, Wingate, and Zurich soils in the same family. Barony (T), Elco, Grays, Kaneville (T), Libre, Mayville, Somonank (T), Windere, Wingate, and Zurich soils contain more than 5 percent sand in parts of the solum above 48 inches. Birkbeck, Downsouth (T), Homen (T), Redbud, and Windfield soils have higher chroma in the lower part of the Bt horizons and lack gleyed colors above 36 inches. Hedrick soils have ochric epipedons that have color value and chroma moist of 3 or less. Iona soils have a thinner solum and contain carbonates at 40 to 50 inches. Rocheport soils have lithic or paralithic contact within a depth of 60 inches.
GEOGRAPHIC SETTING: Inton soils are on short convex to straight sideslopes and coves of drainageways surrounding the nearly level stable upland divides in the loess covered pre-Wisconsin till plain. The loess is 4 to 8 or more feet thick and is underlain by a gray or grayish, loamy or clayey paleosol. Slope gradient ranges from 2 to 18 percent. These soils formed in a deoxidized and leached weathering zone or a thin oxidized and leached zone and the underlying deoxidized and leached zone with redox depletions and redox concentrations and the underlying paleosol derived from glacial till. This weathering zone is stratigraphically related to the gray or grayish, loamy or clayey paleosol. Mean annual air temperature ranges from 47 to 53 degrees F, and mean annual precipitation ranges from 30 to 34 inches. The annual frost free period ranges from 155 to 180 days. Elevation ranges from about 650 to 1400 feet above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Ashgrove, Clinton, Keomah, and Keswick series. Inton soils are downslope from the moderately well drained Clinton soils and the somewhat poorly drained Keomah soils and typically upslope from the somewhat poorly and poorly drained Ashgrove soils and the moderately well drained Keswick soils.
DRAINAGE AND PERMEABILITY: These soils are moderately well drained. Runoff is medium and permeability is moderate. The intermittent apparent water table is from 2.5 to 4 feet for sometime from November through July in most years.
USE AND VEGETATION: Mainly cropped to corn and soybeans with oats and hay in a rotation. Some areas are still in the native vegetation of deciduous trees.
DISTRIBUTION AND EXTENT: Southern and southeastern Iowa. The series is moderately extensive and is in MLRA 108.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Des Moines County, Iowa, 1980.
REMARKS: These soils have been mainly included with the Clinton series in previous surveys.
The gray colors and iron segregations are relict features as they are related stratigraphically to a deoxidized and leached weathering zone.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface to a depth of 8 inches (Ap horizon); argillic horizon - the zone from approximately 8 to 35 inches (Bt1, Bt2, Bt3, and Bt4 horizons); udic moisture regime.