LOCATION OTTOSEN IAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Aquic Hapludolls
TYPICAL PEDON: Ottosen clay loam, on 2 percent slope, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 8 inches; black (10YR 2/1) clay loam, very dark gray (10YR 3/1) dry; weak fine and very fine granular structure; friable; cloddy; few fine roots; slightly acid; abrupt smooth boundary.
A--8 to 12 inches; black (10YR 2/1) clay loam, very dark gray (10YR 3/1) dry; weak fine and very fine granular structure; friable; few fine roots; slightly acid; clear smooth boundary. (Combined thickness of the A horizon is 10 to 16 inches.)
AB--12 to 18 inches; very dark grayish brown (2.5Y 3/2) clay loam, grayish brown (2.5Y 5/2) dry; black (10YR 2/1) and very dark gray (10YR 3/1) coats on faces of peds; some dark grayish brown (2.5Y 4/2) in lower part; weak fine subangular blocky structure parting to weak fine and medium granular; friable; few fine roots; slightly acid; gradual wavy boundary. (2 to 8 inches thick)
Bw1--18 to 28 inches; dark grayish brown (2.5Y 4/2) clay loam; very dark grayish brown (2.5Y 3/2) coats on 30 percent of peds; few fine faint yellowish brown (10YR 5/6) mottles; weak fine prismatic structure parting to weak fine and medium subangular blocky; firm, few fine roots; few thin discontinuous clay films; few fine black, strong brown and dark red concretions (oxides); some very dark grayish brown (2.5Y 3/2) worm casts; slightly acid; gradual smooth boundary.
Bw2--28 to 33 inches; olive gray (5Y 5/2) and olive (5Y 5/3) clay loam; common fine faint light olive brown (2.5Y 5/6) and common fine distinct yellowish brown (10YR 5/8) mottles; weak medium prismatic structure parting to weak fine and medium subangular blocky; friable; few fine strong brown and black concretions (oxides); few calcium carbonate accumulations in soft rounded masses and threadlike powdery streaks; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the Bw horizon is 12 to 26 inches.)
2C--33 to 60 inches; olive gray (5Y 5/2) loam; common fine distinct yellowish brown (10YR 5/6) and yellowish brown (10YR 5/8) mottles; massive; friable; few fine strong brown and black concretions (oxides); some cleavage faces stained with streaks of dark yellowish brown (10YR 4/4) to yellowish brown (10YR 5/6) in the lower part; few calcium carbonate concretions in soft rounded masses and threadlike powdery streaks; strongly effervescent; moderately alkaline.
TYPE LOCATION: Kossuth County, Iowa; about 11 miles southwest of Algona; located about 1,000 feet south and (20 feet west of farm lane) 1,400 feet east of the northwest corner of section 19, T. 94 N., R. 29 W.; USGS West Bend NE topographic quadrangle; lat. 42 degrees 56 minutes 56 seconds N. and long. 94 degrees 19 minutes 11 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: The moderately fine textured sediments are 24 to 40 inches thick. In some pedons the thickness of the solum corresponds to the thickness of the sediments. In other pedons the solum extends a few inches into the underlying material. Solum thickness is typically 30 to 40 inches and ranges from 24 to 50 inches. Depth to free carbonates is about the same as the thickness of the solum but is a few inches less in many pedons. The 10 to 40 inch control section averages from 30 to 35 percent clay and from 15 to 30 percent fine sand or coarser. The moderately fine textured sediments typically average about 10 to 25 percent fine sand or coarser and about 32 to 36 percent clay, but the range in average clay content is 30 to 40 percent. The amount of rock fragments is less than 5 percent, and they are absent in many pedons.
The Ap or A horizon has hue of 10YR or is neutral, value of 2, and chroma of 0 or 1. The A horizon is silty clay loam or clay loam. It is moderately acid to neutral.
The AB horizon has hue of 10YR or 2.5Y, value of 2 or 3, and chroma of 1 or 2.
The upper part of the Bw horizon has hue of 10YR or 2.5Y, value of 4 and chroma of 2. The lower part has 2.5Y or 5Y hue, value of 4 or 5 and chroma of 2 to 4. Texture is silty clay loam or clay loam. The upper part of the Bw horizon typically is slightly acid or neutral, and the lower part typically is slightly alkaline or moderately alkaline.
The 2C horizon typically has hue of 5Y or 2.5Y, value of 5 or 6, and chroma of 2 to 4.
COMPETING SERIES: These are the Crippin, Floyd, Fostoria, Kensett, Merton, Nicollet, Readlyn, Snider, and Wilmonton soils. Crippin soils are calcareous throughout. Floyd soils have a B horizon formed in stratified loamy sediments and are leached more deeply. Fostoria soils have less clay in their sola, and more stratification in the lower B and C horizons. Kensett soils have limestone bedrock within 40 inches. Merton and Nicollet soils have less clay in their sola. Also, Nicollet soils formed entirely in friable, loam glacial till and have a higher content of sand in the upper part of the solum. Readlyn soils are more acid, have less clay in their sola, and the lower part of the B horizon and the C horizon are firm glacial till. Snider soils contain less clay in the solum and are leached of carbonates to a depth of 48 inches or more. Wilmonton soils have firm, clay loam or loam glacial till at depths less than 30 inches and have a more permeable solum.
GEOGRAPHIC SETTING: Ottosen soils typically are on convex slopes of the relatively un-dissected Late Wisconsin till plain. Slope ranges from 0 to 3 percent. Ottosen soils formed in silty clay loam or clay loam sediments that overlie friable glacial till or sediments of loam texture. In contrast to typical relief on the Wisconsin till plain, relief is low, knobs of well drained soils are less common and less distinct, and depressions are few, shallow, and indistinct. Mean annual air temperature is about 45 to 52 degrees F. Mean annual precipitation is about 28 to 32 inches.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Bode, Clarion, Kossuth, Nicollet, and Webster soils. Bode and Kossuth soils form a drainage sequence with Ottosen soils. Clarion, Nicollet and Webster soils form a drainage sequence associated with the Bode, Ottosen, and Kossuth soils, but are lower in clay content. The Ottosen and Nicollet soils are on intermediate elevations. Kossuth and Webster soils are lower on the landscape, and Bode and Clarion soils are higher.
DRAINAGE AND PERMEABILITY: Somewhat poorly drained. Runoff is slow. Permeability is moderately slow in the solum and moderate in the underlying material.
USE AND VEGETATION: Most areas are cultivated. The principal crops are corn and soybeans. Native vegetation was tall prairie grasses.
DISTRIBUTION AND EXTENT: North-central Iowa and possibly south-central Minnesota; the series is of minor extent.
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Kossuth County, Iowa, 1979.
REMARKS: Most of these soils were included with Nicollet in previous surveys. Some have been mapped as Guckeen.