LOCATION ONAMIA WI
Established Series
Rev. DJW
03/2025
ONAMIA SERIES
The Onamia series consists of very deep, well drained soils that formed on nearly level to steep parts of outwash plains, pitted outwash, and valley trains. Slope gradients range from 0 to 30 percent. They formed in loamy sediments 50 to 100 centimeters thick over acid sand and gravel.
TAXONOMIC CLASS: Fine-loamy over sandy or sandy-skeletal, mixed, superactive, frigid Haplic Glossudalfs
TYPICAL PEDON: Onamia loam on a southwest-facing slope of 5 percent cultivated to corn (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 centimeters; Very dark grayish brown (10YR 3/2) loam, light brownish gray (10YR 6/2) dry; moderate very fine subangular blocky structure; friable; common roots; neutral; abrupt smooth boundary. (15 to 25 centimetes thick)
B/E-- 23 to 38 centimeters; Dark yellowish brown (10YR 4/4) heavy loam (Bt); weak fine subangular blocky structure; friable; thin patchy clay films; pale brown (10YR 6/3) loam tongues (E) extend into this horizon and comprise about 30 percent of the horizon; weak thin platy structure; few roots; about 2 percent gravel by volume; common earthworm casts; slightly acid; clear wavy boundary. (13 to 38 centimeters thick)
Bt1-- 38 to 64 centimeters; Dark brown (7.5YR 4/4) heavy loam; weak medium and fine subangular blocky structure; friable; few roots; about 4 percent gravel by volume; thin patchy clay films on faces of peds; tongues of pale brown (10YR 6/3) E material occupy about 5 percent of the horizon as coatings on vertical faces of peds; strongly acid; clear wavy boundary. (13 to 38 centimeters thick)
2Bt2-- 64 to 71 centimeters; Dark brown (7.5YR 4/4) heavy sandy loam; weak medium subangular blocky structure; friable; few roots; thin patchy clay films on faces of peds; about 5 percent gravel by volume; strongly acid; clear wavy boundary. (0 to 10 centimeters thick)
2Bt3-- 71 to 81 centimeters; Dark brown (7.5YR 4/4) loamy coarse sand; weak coarse subangular blocky structure; very friable; few roots; clay bridging between sand grains; about 11 percent gravel by volume; strongly acid; clear wavy boundary. (0 to 25 centimeters thick)
2C-- 81 to 152 centimeters; Reddish yellow (7.5YR 6/6) stratified coarse sand and gravel; single grained; loose; slightly acid.
TYPE LOCATION: Polk County, Wisconsin; 504 feet west and 1920 feet north of the southeast corner of Sec. 4, T. 32 N., R. 18 W.
RANGE IN CHARACTERISTICS: The thickness of the solum ranges from 60 to 100 centimeters. Thickness of the upper loamy mantle is 50 to 90 centimeters thick. The solum is neutral to strongly acid and the 2C horizon is slightly acid to neutral. Free carbonates are lacking to depths of more than 200 centimeters. Gravel content ranges from 0 to 7 percent in the upper part of the solum, 2 to 20 percent in the 2Bt horizon, and 10 to 60 percent in the 2C horizon. Mean annual soil temperature ranges from 42 to 47F.
The Ap horizon has 10YR hue, value of 3 or 4, and chroma of 2 or 3. Value is greater than 5.5 when dry. Some pedons have a 2 to 10 centimeter thick A1 horizon with 10YR hue, value of 2 or 3, and chroma of 1 or 2. The Ap or A1 horizon is silt loam, loam, or fine sandy loam with granular or subangular blocky structure.
The A2 horizon has 10YR or 7.5YR hue, value of 4 through 6. and chroma of 2 or 3. It is silt loam, loam, fine sandy loam or very fine sandy loam. Structure is platy or subangular blocky.
The E horizon is lacking in many pedons, but where present, it is 2 to 25 centimeters thick.
The E/B or B/E horizons have tongues of E material surrounding thin, column-like upward extensions of the Bt horizons or wholly surrounding small isolated remnants of the Bt horizon. The tongues of E have 10YR or 7.5YR hue, value of 4 through 6, and chroma of 2 or 3. The E part is like the E horizon described above. The Bt part of the horizon is like the B2t horizon described below.
The Bt2 horizon has 10YR or 7.5YR hue, value of 4 or 5, and chroma of 3 or 4. It is loam, clay loam, or sandy clay loam. The 2Bt2 horizon has 10YR, 7.5YR or 5YR hue, value of 4 or 5, and chroma of 3 through 6. It is sandy clay loam, sandy loam, or gravelly sandy loam.
The 2Bt3 horizon has 10YR, 7.5YR, or 5YR hue, value of 4 or 5, and chroma of 3 through 6. It is gravelly sandy loam, loamy sand, loamy coarse sand, gravelly loamy sand, or gravelly loamy coarse sand. Clay films in the Bt horizons are thin and patchy on faces of most peds. Clay bridging is common in the lower part of the solum.
The 2C has 10YR, 7.5YR, or 5YR hue, value and chroma of 3 through 6. It is typically stratified medium or coarse sand and gravel, but in some pedons it is gravelly or very gravely coarse sand.
COMPETING SERIES: Onamia is the only series in this family. Other closely related series in other families are
Antigo,
Brill,
Chetek, EauPleine,
Freeon,
Halder,
Marathon, llarquette,
Rosholt,
Santiago and
Scott Lake. Antigo soils are similar but are fine-silty over sandy or sandy-skeletal. Brill soils are fine-silty and have mottles of low chroma in the lower part of the sola. Chetek soils are coarse-loamy, have thinner sola, and lack tonguing. EauPleine soi.ls are coarse-loamy and formed mainly in residuum weathered from granitic rocks. Freeon soils are fine-loamy and underlain by sandy loam glacial till. Halder soils are fine-loamy over sandy or sandy-skeletal but have mottles of low chroma in the upper 25 centimeters of the argillic horizon. Marathon soils are coarse-loamy, have thicker sola, and have bedrock between a depth of 100 and 150 centimeters.
Marquette soils are coarse-loamy and have a calcaeous coarse-textured 2C horizon beginning at a depth of 30 to 60 centimeters. Rosholt soils are similar, but coarse-loamy. Santiago soils are fine-loamy and underlain by sandy loam glacial till. Scott Lake soils have mottles of low chroma in the lower part of the solum.
GEOGRAPHIC SETTING: These soils are on nearly level to steep parts of outwash plains, pitted outwash, and valley trains. Slope gradients range from 0 to 30 percent. They formed in loamy sediments 50 to 100 centimeters thick over acid sand and gravel. The climate is udic with short summers and long cold winters. Mean annual air temperature ranges from 42 to 45F. Mean annual precipitation ranges from 71 to 81 centimeters.
GEOGRAPHICALLY ASSOCIATED SOILS: The moderately well drained
Scott Lake soils, the somewhat poorly drained
Halder soils, and the poorly drained
Warman soils are in a drainage sequence with the Onamia soils. The well drained
Antigo soils are common associates in some places. In other places, the Onamia soils are in intricate patterns with the well drained
Amery soil and the somewhat excessively drained
Chetek soils.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: Well drained. Surface runoff is slow to rapid. Permeability is moderate in the solum and very rapid in the substratum.
USE AND VEGETATION: Most cleared areas are cropped to corn, oats, and grasses and legumes, but some are used for pasture. The remaining areas are in woodland. The native vegetation was mixed deciduous and coniferous forest with red oak, maple, birch, aspen, and white pine predominating. Small areas of these soils are used as a source of sand and gravel.
DISTRIBUTION AND EXTENT: Central and east-central Minnesota and northern Wisconsin. It is not extensive.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: SALINA, KANSAS
SERIES ESTABLISHED: Mille Lacs County, Minnesota, 1927.
REMARKS: These soils formerly were classified as Gray Brown Podzolic soils. The responsibility of the Onamia series was transferred from Minnesota to Wisconsin in December 1973. It has previously been placed with the coarse-loamy, mixed family of Typic Eutroboralfs. Soils that have recently been called Onamia (coarse-loamy family) will be placed in the Rosholt series.
This series was inactive for a period of time then reactivated because it is still correlated in publish soil survey data.
Additional Data - Refer to Soil Survey Investigations Report No. 17 "Soil Survey Laboratory Data and Descriptions for Some Soils of Wisconsin" for some data on a pedon of this series.
National Cooperative Soil Survey
U.S.A.