LOCATION PIOPOLIS IL+IN MO OHEstablished Series
The Piopolis series consists of very deep, poorly drained and very poorly drained, slowly permeable soils formed in silty alluvium on flood plains or flood-plain steps within lake plains. Slopes range from 0 to 2 percent. Mean annual temperature is about 55 degrees F., and mean annual precipitation is about 43 inches.
TAXONOMIC CLASS: Fine-silty, mixed, active, acid, mesic Fluvaquentic Endoaquepts
TYPICAL PEDON: Piopolis silty clay loam - nearly level in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; grayish brown (10YR 5/2) silty clay loam, light brownish gray (10YR 6/2) dry; weak medium granular structure; friable; slightly acid; abrupt smooth boundary (5 to 12 inches thick)
Bg1--7 to 14 inches; light brownish gray (10YR 6/2) silty clay loam; weak coarse subangular blocky structure; firm; common medium prominent strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; common medium faint gray (10YR 6/1) iron depletions in the matrix; strongly acid; gradual smooth boundary.
Bg2--14 to 23 inches; gray (10YR 6/1) silty clay loam; weak coarse subangular blocky structure; firm; many medium prominent strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; few dark iron and manganese concretions; strongly acid; gradual smooth boundary.
Bg3--23 to 37 inches; gray (10YR 6/1) silty clay loam; weak coarse subangular blocky structure; firm; many medium prominent strong brown (7.5YR 5/6) and common medium distinct yellowish brown (10YR 5/4) masses of iron accumulation in the matrix; common black iron and manganese concretions; strongly acid; gradual smooth boundary. (The combined thickness of the Bg horizons is 8 to 48 inches thick)
Cg--37 to 60 inches; gray (10YR 6/1) silty clay loam; massive; firm; few coarse prominent strong brown (7.5YR 5/6) masses of iron accumulation in the matrix; strongly acid.
TYPE LOCATION: Hamilton County, Illinois; about 10 miles north of McLeansboro; 1,340 feet south and 1,300 feet west of the center of sec. 26, T. 3 S., R. 6 E.; USGS Belle Prairie City, IL. topographic quadrangle; lat. 38 degrees 13 minutes 47 seconds N. and long. 88 degrees 30 minutes 55 seconds W. NAD 27.
RANGE IN CHARACTERISTICS: The particle-size control section averages 27 to 35 percent clay and less than 15 percent sand. This soil has an irregular decrease in organic carbon content with increasing depth, but in some pedons the irregular decrease is slight. The soil is not dry in all parts of the soil moisture control section for 45 or more days during the 120 days following the summer solstice.
The Ap or A horizon has hue of 10YR, 2.5Y, or 5Y, value of 4 to 6, and chroma of 1 to 3. Redox concentrations have redder hue and higher chroma. Texture is silty clay loam, or less commonly silt loam. Clay content ranges from 20 to 35 percent and sand content is less than 20 percent. Reaction ranges from strongly acid to neutral, depending on liming history.
The Bg or Cg horizon, above a depth to 40 inches, has hue of 10YR, 2.5Y, 5Y, or is neutral; value of 4 to 7; and chroma of 0 to 2. Redox concentrations have redder hue and higher chroma. Texture is silty clay loam and averages 27 to 35 percent clay and less than 15 percent sand. Reaction is very strongly acid or strongly acid.
The Bg or Cg horizon, below a depth of 40 inches, is dominantly silty clay loam, or silt loam, and includes thin strata of fine sandy loam, loam, or silty clay. It averages 25 to 38 percent clay and less than 30 percent sand. Reaction ranges from strongly acid to neutral, and typically increases with depth.
COMPETING SERIES: This is the Stendal series. Stendal soils have at least one horizon between the A or Ap horizon and a depth of 30 inches that has both a color value, moist, and chroma of 3 or more or chroma of 2 or more if there are no redox concentrations.
GEOGRAPHIC SETTING: Piopolis soils are in backlands and backswamps of flood plains or flood-plain steps within lake plains. Slope gradients commonly are less than 1 percent, and range from 0 to 2 percent. Piopolis soils formed in silty alluvium. The alluvium is silty clay loam in the upper part. Mean annual air temperature ranges from 54 to 58 degrees F.; mean annual precipitation ranges from 38 to 45 inches, frost free period ranges from 180 to 200 days, and elevation ranges from 340 to 600 feet above sea level.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bonnie, Cape, Jacob, Karnak, Stendal, and Zipp soils. The poorly drained and/or very poorly drained Birds, Bonnie, Cape, and Petrolia soils are on backlands or backswamps of flood plains. Bonnie soils contain less clay in the particle-size control section. Cape, Jacob, and Karnak soils contain more clay in the particle-size control section and are typically in backswamps. The somewhat poorly drained Stendal soils are on slightly higher flood-plain steps. The very poorly drained, more clayey Zipp soils are on flats and depressions of lake plains.
DRAINAGE AND PERMEABILITY: Poorly drained and very poorly drained. The potential for surface water runoff is low or negligible. Permeability is slow. Flooding from stream overflow is common during late winter and spring. In the undrained condition, these soils have an intermittent apparent water table from 2 feet above the surface to at the surface during November through June in most years. Where drained, the intermittent water table will be from 1 foot above the surface to 1 foot below during December through May in most years.
USE AND VEGETATION: Most areas are used to grow corn and soybeans. Some areas are in forest or are used for pasture. Native vegetation is hardwood trees.
DISTRIBUTION AND EXTENT: Southern Illinois, southern Indiana, northeastern Missouri, and southeastern Ohio. Piopolis soils are of large extent (more than 125,000 acres correlated).
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Johnson County, Illinois, 1954.
REMARKS: This soil was reclassified (3/2002) as an inceptisol based on the Eighth Edition of the "Keys to Soil Taxonomy" and the presence of a cambic horizon in the majority of pedons. In most areas these soils have been described as having weak or moderate blocky structure through the middle part of the series control section.
Diagnostic horizons and features recognized in this pedon are: ochric epipedon - the zone from the surface to a depth of 7 inches (Ap horizon); cambic horizon - the zone from 7 to 37 inches (Bg1, Bg2, Bg3 horizons); aquic conditions throughout.