LOCATION DENNY ILEstablished Series
TAXONOMIC CLASS: Fine, smectitic, mesic Mollic Albaqualfs
TYPICAL PEDON: Denny silt loam - on a 0.5 percent concave slope in a depression in a cultivated field at an elevation of 722 feet (220 meters) above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches (0 to 20 cm); very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; weak fine granular structure; very friable; few very fine roots throughout; moderately acid; abrupt smooth boundary. (Combined thickness of all A horizons is about 7 to 9 inches or 18 to 24 cm thick.)
Eg1--8 to 14 inches (20 to 36 cm); dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; weak thick platy structure parting to weak thin platy; very friable; few very fine roots throughout; few distinct very dark gray (10YR 3/1) organic coatings in root channels; common faint grayish brown (10YR 5/2) clay depletions on faces of peds; common fine prominent dark yellowish brown (10YR 3/6) masses of iron and manganese accumulation throughout; few fine distinct black (N 2/) manganese concretions in the matrix; moderately acid; clear smooth boundary.
Eg2--14 to 21 inches (36 to 53 cm); grayish brown (10YR 5/2) silt loam, light gray (10YR 7/2) dry; weak thick platy structure parting to moderate medium platy; friable; few very fine roots throughout; few distinct very dark gray (10YR 3/1) organic coatings in root channels; common fine faint dark brown (10YR 3/3) masses of iron and manganese accumulation throughout; common fine prominent black (N 2/) manganese concretions in the matrix; moderately acid; abrupt smooth boundary. (Combined thickness of all Eg horizons is about 4 to 15 inches or 10 to 36 cm thick)
Btg1--21 to 29 inches (53 to 74 cm); grayish brown (10YR 5/2) silty clay loam; moderate fine and medium subangular blocky structure; firm; few very fine roots between peds; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few distinct very dark gray (10YR 3/1) organic coatings in root channels; many fine prominent dark yellowish brown (10YR 4/6) and common fine distinct yellowish brown (10YR 5/4) masses of iron and manganese accumulation throughout; common fine prominent black (N 2/) manganese concretions in the matrix; moderately acid; clear smooth boundary.
Btg2--29 to 38 inches (74 to 97 cm); grayish brown (10YR 5/2) silty clay loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; few very fine roots between peds; common faint dark grayish brown (10YR 4/2) clay films on faces of peds; few distinct very dark gray (10YR 3/1) organic coatings in root channels; many fine prominent dark yellowish brown (10YR 4/6) iron and manganese and common fine prominent yellowish brown (10YR 5/8) masses of iron accumulation throughout; common fine prominent black (N 2/) manganese concretions in the matrix; moderately acid; gradual smooth boundary.
Btg3--38 to 46 inches (97 to 117 cm); light brownish gray (2.5Y 6/2) silty clay loam; moderate coarse prismatic structure parting to moderate coarse subangular blocky; firm; very few fine roots between peds; common distinct dark grayish brown (10YR 4/2) clay films on faces of peds; few distinct very dark gray (10YR 3/1) organic coatings in root channels; many fine prominent dark yellowish brown (10YR 4/6) iron and manganese and common fine prominent strong brown (7.5YR 5/6) masses of iron accumulation throughout; common fine prominent black (N 2/) manganese concretions in the matrix; moderately acid; gradual wavy boundary. (Combined thickness of all Btg horizons is about 25 to 50 inches or 63 to 127 cm thick)
Cg--46 to 60 inches (117 to 152 cm); light brownish gray (2.5Y 6/2) silty clay loam; massive; firm; few very fine roots along plains of weakness in the loess; very few distinct very dark gray (10YR 3/1) organic coatings in root channels; many fine prominent dark yellowish brown (10YR 4/6) iron and manganese and common fine prominent strong brown (7.5YR 5/6) masses of iron accumulation throughout; few medium prominent black (N 2/) manganese concretions in the matrix; slightly acid; diffuse wavy boundary.
TYPE LOCATION: McDonough County, Illinois; about 1/4 mile west of Good Hope, 225 feet north and 1,680 feet east of the southwest corner of sec. 25, T. 7 N., R. 3 W. Lat. 40 degrees 33 minutes 31 seconds N. and long. 90 degrees 41 minutes 15 seconds W. or UTM zone15T 0695797E 4492335N, NAD 83.
RANGE IN CHARACTERISTICS: The depth to the base of the argillic horizon ranges from 40 to 65 inches (102 to 165 cm). The particle size control section averages between 35 and 40 percent clay. The series control section has sand content of less than 8 percent. The soil temperature in the temperature control section averages between 47 and 56 degrees F. (8.3 to 13.3 degrees C.).
The Ap or A horizon has value of 2 or 3 (4 or 5 dry) and chroma of 1 or 2. Texture is silt loam and averages between 12 and 27 percent clay. Reaction ranges from moderately acid to neutral.
The Eg horizon has hue of 10YR or 2.5Y; value of 4 to 6; and chroma of 1 or 2. It is silt loam and averages between 15 and 27 percent clay. Reaction ranges from moderately acid to slightly acid.
The Btg horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 1 or 2. Redoximorphic feature colors include hue of 7.5YR and chroma as high as 8. Texture is silty clay loam or silty clay and averages between 35 and 40 percent clay. Individual subhorizons have 32 to 45 percent clay. Reaction is moderately acid or slightly acid in the upper part and moderately acid to slightly alkaline in the lower part.
The Cg horizon has hue of 10YR, 2.5Y, or 5Y; value of 4 to 6; and chroma of 1 or 2. Chroma of redox features range as high as 8. The Cg horizon is silt loam or silty clay loam. It ranges from 10 to 32 percent clay and less than 5 percent sand. Reaction ranges from slightly acid to slightly alkaline and lacks carbonates above a depth of 60 inches.
COMPETING SERIES: These are the Brooklyn, Cisne, Cowden, and Smileyville series. Brooklyn and Cisne soils have more than 8 percent fine sand or coarser in the lower part of the series control section. Cowden soils are in areas with that average more than 54 degrees F. (12.2 degrees C.) in the soil temperature control section. Smileyville soils average more than 40 percent clay in the particle size control section.
GEOGRAPHIC SETTING: Denny soils are typically in shallow depressions on loess covered ground moraines. Less commonly they occur on nearly level low summits and talfs. Slopes are 0 to 2 percent. They formed in loess. Mean annual air temperature ranges from 45 to 54 degrees F. (7.2 to 12.2 degrees C.), mean annual precipitation ranges from 34 to 39 inches (864 to 991 mm), and frost free days range from 150 to 190. Elevation ranges from 400 to 830 feet (122 to 253 meters) above mean sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Atterberry, Edgington, Ipava, Muscatune, Osco and Sable, soils. Atterberry, Ipava, Muscatune, and Osco soils are on nearby, slightly higher, non-depressional positions and are better drained. Edgington soils are on similar positions, have mollic epipedons and have less clay in the argillic horizons. Sable soils are Mollisols and do not have an albic horizon. They are on nearby similar topographic positions.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Denny soils are poorly drained. The potential for surface runoff is negligible. Permeability is slow (moderately low saturated hydraulic conductivity). In the undrained condition, these soils have an apparent water table from 0 to 6 inches below the surface from November through June in normal years and also pond water from 0 to 6 inches above the surface for long to very long periods from November to June in most years. In the drained condition, these soils have an apparent water table from 0 to 12 inches below the surface from January through May in normal years and also pond water from 0 to 6 inches above the surface for brief periods from January through May. The water table and ponding depth may vary based on local precipitation amounts..
USE AND VEGETATION: Most areas are used to grow corn and soybeans. Some undrained areas are used for pasture. Native vegetation is sedges and grasses.
DISTRIBUTION AND EXTENT: Central, western, and northwestern Illinois. The extent is moderate (nearly 14,000 acres correlated) in MLRAs 108B and 115C.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Warren County, Illinois, 1932.
REMARKS: The type location was moved from Jersey County to McDonough County, 3/2006. The new location site is more central to the overall extent of the Denny series mapped in Illinois.
Diagnostic horizons and features recognized in this pedon are:
1) ochric epipedon - the zone from the surface to a depth of 21 inches (Ap, Eg1, and Eg2 horizons);
2) albic horizon - the zone from 8 to 21 inches (Eg1 and Eg2 horizons);
3) argillic horizon - the zone from 21 to 46 inches (Btg1, Btg2, and Btg3 horizons).