LOCATION OMULGA OHEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, active, mesic Oxyaquic Fragiudalfs
TYPICAL PEDON: Omulga silt loam - on a 2 percent convex slope in a cultivated field. (Colors are for moist soils unless otherwise stated.)
Ap--0 to 11 inches; dark brown (10YR 4/3) silt loam; pale brown (10YR 6/3) dry; weak fine granular structure; friable; common fine roots; 1 percent rock fragments; neutral; abrupt smooth boundary. (8 to 12 inches thick)
Bt1--11 to 17 inches; yellowish brown (10YR 5/4) silt loam; weak fine subangular blocky structure; friable; few fine roots; thin very patchy yellowish brown (10YR 5/6) clay films on faces of peds; 1 percent rock fragments; strongly acid; clear smooth boundary.
Bt2--17 to 22 inches; yellowish brown (10YR 5/4) silt loam; moderate medium subangular blocky structure parting to weak medium platy; friable; few fine roots; thin patchy yellowish brown (10YR 5/6) clay films on faces of peds; thick continuous light yellowish brown (10YR 6/4) silt coatings on vertical faces of peds; 1 percent rock fragments; very strongly acid; gradual wavy boundary. (Combined thickness of the Bt horizon is 9 to 20 inches.)
B/E--22 to 27 inches; yellowish brown (10YR 5/6) silt loam (Btx); few medium faint strong brown (7.5YR 5/6) mottles; weak coarse prismatic structure parting to moderate medium platy; very firm, some brittleness; medium patchy dark yellowish brown (10YR 4/4) clay films on faces of peds; very thick continuous pale brown (10YR 6/3) silt coatings on vertical faces of peds (E) (10 to 15 percent volume); 1 percent rock fragments; extremely acid; clear wavy boundary. (0 to 6 inches thick)
Btx1--27 to 38 inches; yellowish brown (10YR 5/6) silt loam; moderate very coarse prismatic structure parting to moderate medium platy; very firm, brittle; medium patchy yellowish brown (10YR 5/6) clay films on faces of peds; thick continuous light brownish gray (10YR 6/2) silt coatings on vertical faces of peds; yellowish brown (10YR 5/8) rind between the coating and ped interior; 1 percent rock fragments; extremely acid; gradual smooth boundary.
Btx2--38 to 49 inches; yellowish brown (10YR 5/6) silt loam; moderate very coarse prismatic structure; very firm, brittle; medium patchy yellowish brown (10YR 5/6) clay films on faces of peds; thick continuous light brownish gray (10YR 6/2) silt coatings on vertical faces of peds; yellowish brown (10YR 5/8) rind between the coating and ped interiors; 1 percent rock fragments; very strongly acid; gradual smooth boundary. (Combined thickness of the Btx horizon is 13 to 36 inches.)
B't1--49 to 65 inches; yellowish brown (10YR 5/6) silty clay loam; moderate very coarse prismatic structure parting to weak fine subangular blocky; very firm; thin very patchy yellowish brown (10YR 5/6) clay films on faces of peds; thick continuous light brownish gray (10YR 6/2) silt coatings on vertical faces of peds; 1 percent rock fragments; very strongly acid; gradual smooth boundary. (0 to 36 inches thick)
2B't2--65 to 71 inches; yellowish brown (10YR 5/4) clay; weak coarse prismatic structure; very firm; very strongly acid; gradual smooth boundary. (0 to 24 inches thick)
2BC--71 to 79 inches; yellowish brown (10YR 5/6) sandy clay loam; weak coarse prismatic structure; firm; very strongly acid; gradual smooth boundary. (0 to 24 inches thick)
2C--79 to 85 inches; yellowish brown (10YR 5/4) sandy loam; massive; friable; very strongly acid.
TYPE LOCATION: Jackson County, Ohio; 1,400 feet west and 600 feet south of the northeast corner, sec. 30, T. 6 N., R. 19 W.
RANGE IN CHARACTERISTICS: Thickness of the solum ranges from 40 to 100 inches. Depth to the fragipan ranges from 18 to 36 inches. Volume of rock fragments, generally water-worn gravel, ranges up to 5 percent above the fragipan, up to 10 percent in the Btx, B't or BC horizons, and up to 15 percent in the 2B't, 2BC, and 2C horizons.
The Ap horizon has hue of 10YR, value of 4 or 5 moist and 6 or 7 dry, and chroma of 2 or 3. Some pedons have an A horizon, 1 to 4 inches thick, that has value of 2 or 3 and chroma of 1 or 2, and an E horizon, 3 to 8 inches thick, that has value of 5 or 6 and chroma of 3 or 4. The A and E horizons are very strongly acid to moderately acid, but range to neutral where limed.
Some pedons have a BA horizon or an AB horizon.
The Bt horizon has hue of 10YR or 7.5YR, value of 4 or 5, and chroma of 3 to 8. Some pedons have mottles with chroma of 2 or less in the lower part of the Bt horizon above the fragipan but not within the upper 10 inches of the argillic horizon. The Bt horizon is silt loam or silty clay loam. It is strongly acid to extremely acid.
Some pedons have an E horizon rather than a B/E horizon.
The Btx horizon has hue of 10YR or 7.5YR, value of 4 to 6, and chroma of 3 to 6. It is silt loam or silty clay loam. It is strongly acid to extremely acid. B't or BC horizons have colors similar to the Btx horizon. It is silt loam or silty clay loam. It is very strongly acid to moderately acid. Some pedons have a Btx horizon below a depth of 40 inches that ranges to clay loam.
The 2B't, 2BC, and 2C horizons have hue of 7.5YR, 10YR, or 2.5Y; value of 4 to 6; and chroma of 2 to 6. They typically are stratified and range from sandy loam to clay. They commonly are very strongly acid to moderately acid but range to neutral in thick layers of silty clay and clay.
In pedons that have a 2B horizon at a depth of less than 24 inches, a 3B or 3C horizon commonly is identified at the contact with underlying stratified materials.
COMPETING SERIES: These are the Aldino, Ava, Boston, Cincinnati, Grantsburg, Hildebrecht, Hosmer, Lawrenceville, Mercer, Nicholson, Otwell, Rainsboro, Weisburg, and Zanesville series. A similar soil is the Monongahela series. Aldino soils have angular pebbles of quartzite and flakes of mica in the lower part of the solum. Ava soils have bisequal soil development. Boston, Mercer, Nicholson, and Weisburg soils formed partly in residuum from bedrock and do not have stratification in the lower part. In addition, Boston and Weisburg soils have some coarse fragments of mixed lithology from glacial till, Boston soils have redder hue, and Mercer soils have thinner solum. Cincinnati soils have mixed coarse fragments from glacial till in the lower part of the solum. Grantsburg and Hosmer soils formed in loess do not have stratification in the lower part of the solum, and do not contain coarse fragments. Hildebrecht soils have fragments of chert in the lower part of the solum. Lawrenceville soils have a more mottled fragipan and do not have silty coatings in the upper part of the fragipan. Otwell soils have stratified materials at depths of less than 40 inches and typically are less acid in the B and C horizons. Rainsboro soils have a higher content of gravel and sand in the lower part of the solum. Zanesville soils have lower part of the sola formed in sandy loam residuum weathered from acid sandstone. Monongahela soils contain more sand in the control section and have a lower base saturation at 30 inches below the top of the fragipan.
GEOGRAPHIC SETTING: Omulga soils are in valley fills in an abandoned preglacial drainage system of the Allegheny Plateau. Slope gradients are 0 to 15 percent. The soils formed in loess, colluvium or old alluvium, and in most areas by underlying lacustrine sediments. The loess mantle ranges up to 24 inches in thickness. Mean annual precipitation ranges from about 38 to 43 inches, and mean annual temperature ranges from about 52 to 56 degrees F.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Allegheny, Doles, Richland, Tygart, and Wyatt soils. Allegheny and Wyatt soils are on similar landscape positions. Allegheny soils are fine-loamy and Wyatt soils are fine. Doles soils are somewhat poorly drained and are on nearly level areas. Richland soils are fine-loamy and are on toe slopes below areas of bedrock. Tygart soils are nearly level, somewhat poorly drained, and have more clay.
DRAINAGE AND PERMEABILITY: Moderately well drained. Surface runoff is slow to rapid. Permeability is moderate above the fragipan and slow in the fragipan. Water is perched above the fragipan during late winter and spring months.
USE AND VEGETATION: Most areas of these soils are used for cultivated crops, including corn and wheat, meadow, and pasture. Original vegetation was deciduous hardwood forest.
DISTRIBUTION AND EXTENT: Southern Ohio and possibly West Virginia. The series is of large extent.
MLRA OFFICE RESPONSIBLE: Morgantown, West Virginia
SERIES ESTABLISHED: Jackson County, Ohio, 1981.
REMARKS: Classification was adjusted to agree with ST Issue #17 on 22 Sept 94 by CLG. The Omulga series was formerly included with the Otwell series. Omulga soils are in unglaciated areas which lack influence from glaciated areas; whereas, Otwell soils have formed in outwash or lacustrine sediments from glaciated areas. In addition, Otwell soils do not have perching of water above the fragipan.
ADDITIONAL DATA: Characterization data from the Ohio State University on JK-13, the typical pedon, is attached. Other data includes PK-6 and SC-10.