LOCATION VELMA ILEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Argiudolls
TYPICAL PEDON: Velma silt loam - with a 12 precent south-facing slope, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 7 inches; very dark grayish brown (10YR 3/2) silt loam, dark grayish brown (10YR 4/2) dry; moderate very fine and fine granular structure; very friable; many very fine and fine roots; neutral; abrupt smooth boundary.
A--7 to 16 inches; very dark grayish brown (10YR 3/2) loam, dark grayish brown (10YR 4/2) dry; moderate fine and medium granular structure; friable; common very fine and fine roots; few yellowish brown (10YR 5/4) soil fragments or worm casts; 3 percent pebbles; medium acid; clear smooth boundary. (Combined thickness of the A horizons is 10 to 18 inches.)
Bt1--16 to 26 inches; yellowish brown (10YR 5/4) clay loam; moderate fine and medium subangular blocky structure; friable; common fine roots; many distinct dark brown (10YR 4/3) clay films on faces of peds; 3 percent pebbles; strongly acid; clear smooth boundary.
Bt2--26 to 34 inches; yellowish brown (10YR 5/4) clay loam; few fine faint yellowish brown (10YR 5/6) mottles; moderate fine and medium subangular blocky structure; friable; few fine roots; many distinct brown (10YR 5/3) clay films on faces of peds; 3 percent pebbles; strongly acid; clear smooth boundary.
Bt3--34 to 47 inches; mottled yellowish brown (10YR 5/4 and 10YR 5/8), and pale brown (10YR 6/3) clay loam; moderate fine and medium subangular blocky structure; friable; few distinct dark brown (10YR 4/3) clay films on faces of peds; 3 percent pebbles; medium acid; clear smooth boundary.
Bt4--47 to 54 inches; mottled yellowish brown (10YR 5/6 and 10YR 5/4) clay loam; weak medium subangular blocky structure; friable; few distinct dark brown (10YR 4/3) clay films on faces of peds; 3 percent pebbles; slightly acid; clear smooth boundary. (Combined thickness of the Bt horizons is 20 to 45 inches.)
C--54 to 60 inches; pale brown (10YR 6/3) loam; common medium distinct yellowish brown (10YR 5/6) mottles; weak very coarse subangular blocky structure; friable; common distinct brown (10YR 4/3) clay films on vertical faces of peds; 3 percent pebbles; strong effervescence; moderately alkaline.
TYPE LOCATION: Macoupin County, Illinois; about 8 miles west and 2 miles south of Carlinville; 1000 feet south and 1200 feet west of the center of sec. 6, T. 9 N., R. 8 W.
RANGE IN CHARACTERISTICS: The solum is 42 to more than 60 inches in thickness. The mollic epipedon is 10 to 24 inches in thickness. The loess mantle is 0 to 20 inches in thickness. The depth to free carbonates is between 42 and 60 inches. The upper 20 inches of the argillic horizon averages between 25 and 45 percent fine and coarser sand, and between 25 to 35 percent clay. Glacial pebbles range from 0 to 15 percent throughout the part of the solum formed in till, and gennerally are absent in the surface and subsurface layers that formed in loess. A few cobbles may be present.
The Ap and A horizons have hue of 10YR, value of 2 or 3 (4 or 5 dry), and chroma of 1 through 3. They are silt loam or loam except in some eroded or severely eroded pedons the surface layer is clay loam and contains some pebbles and cobbles. They are neutral to strongly acid.
Some pedons have an AB and BA horizon. Some pedons have a thin silty clay loam Bt horizon formed in loess.
The Bt or 2Bt horizon that formed in till has hue of 7.5YR or 10YR, value of 4 or 5, and chroma of 3 through 8. Some mottling is common and some pedons contain chroma of 2 or less or iron and manganese oxides in the middle and lower parts. The Bt or 2Bt horizon commonly is clay loam and less commonly is loam. It is very strongly acid or strongly acid in the upper part and strongly acid to neutral in the lower part.
Some pedons have a BC or 2BC horizon as much as 10 inches in thickness.
The C or 2C horizon has hue of 7.5YR or 10YR, value of 5 or 6, and chroma of 3 through 8 and commonly is mottled. It is clay loam, loam, or sandy loam and commonly contains between 2 and 15 percent fine gravel. It is mildly alkaline or moderately alkaline.
COMPETING SERIES: These are the Atkinson, Barce, Burchard, Calmar, Corwin, Cresco, Durand, Foresman, Friesland, Griswold, Hitt, Hochheim, Jasper, Joslin, La Rose, Linkville, Markesan, Moingona, Mona, Morrill, Pana, Parr, Plattville, Prairieville, Ringwood, Rockton, Rotamer, Schoolcraft, Shelby, Sibleyville, Symerton, Tippecanoe, Wea, and Winnebago series in the same family. Atkinson, Joslin, and Mona soils contain more clay in the lower part of the solum. Barce soils have the lower solum formed in loamy outwash and glacial till. Burchard soils contain free carbonates within a depth of 30 inches. Calmar, Rockton, and Sibleyville soils have bedrock within a depth of 40 inches. Corwin, Griswold, Hochheim, La Rose, Markesan, Parr, Ringwood, and Rotamer soils have thinner sola. In addition, Parr and Ringwood soils are not strongly acid in any part of the solum, and Ringwood soils contain more sand in the lower part of the solum. Cresco soils typically contain more sand in the upper part of the solum and have gray colors with chroma 0 or 1 in the matrix and on the faces of the peds in the lower part of the solum. Durand, Hitt, and Winnebago soils have redder colors with hue of 5YR in some part of the subsoil. Foresman soils have the lower part of the B horizon and C horizon formed in stratified fine sand and silt and typically have a thinner solum. Friesland, Moingona, Plattville, Shelby, and Symerton soils are not strongly acid in any part. In addition, Friesland and Symerton soils contain less sand in the lower part of the solum, and Shelby soils contain a higher content of montmorillonitic clay. Jasper soils contain less clay in the lower part of the solum and formed in stratified sediments. Linkville soils average less than 25 percent clay in the control section and contain less clay in the lower part of the solum. Morrill soils typically have, in the B horizon, hue of 5YR, and lack hue of 10YR or yellower. Pana, Tippecanoe, and Wea soils contain more sand and gravel in the lower part of the solum. In addition, Pana soils lack hue of 10YR or yellower in the B horizon, and Tippecanoe and Wea soils contain less clay in the lower part of the solum. Prairieville soils formed in loamy eolian deposits and the underlying till on old erosional surface on till plains and have slopes less than 5 percent. They typically contain more sand in the upper part of the solum and are leached of free carbonates to depths greater than 60 inches. Schoolcraft soils contain more sand and less clay in the lower part of the solum and have sand or gravelly sand within a depth of 40 inches.
GEOGRAPHIC SETTING: Velma soils are on sloping to moderately steep side slopes of drainageways on dissected loess-covered till plains. Slope gradients range from 4 to 20 percent. Velma soils formed in glacial till, typically of Illinoian age, with a mantle of loess less than 20 inches in thickness on many pedons. They are downslope from the Sangamon paleosol that formed in the upper part of the Illinoian till. Mean annual temperature varies from 50 to 54 degrees F, and mean annual precipitation varies from 32 to 38 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are Assumption, Coatsburg, Elkhart, Harrison, Keller, and Tama soils. All these soils are upslope from the Velma soils. The well drained or moderately well drained Assumption soils and the somewhat poorly drained Keller soils formed in 20 to 40 inches of loess and the underlying till and contain a paleosol in the underlying till. The poorly drained Coatsburg soils formed in thin loess and the underlying till and contain a paleosol in the till. The well drained Elkhart soils and well drained or moderately well drained Tama soils formed entirely in loess. In addition, Elkhart soils contain free carbonates within a depth of 40 inches. The moderately well drained Harrison soils formed in 40 to 60 inches of loess and in the uderlying silty or loamy materials.
DRAINAGE AND PERMEABILITY: Well drained or moderately well drained. Runoff is medium on the sloping areas and rapid on the strongly sloping and moderately steep areas. Permeability is moderate.
USE AND VEGETATION: These soils are used for cropland or forage for hay or pasture. Corn is the principal row crop. Native vegetation was prairie grasses.
DISTRIBUTION AND EXTENT: Central and western Illinois. The extent is moderate.
MLRA OFFICE RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Christian County, Illinois, 1937.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface of the soil to a depth of 16 inches (Ap and A horizon); argillic horizon - the zone from about 16 to 54 inches (Bt1, Bt2, Bt3, and Bt4 horizons).