LOCATION TRIPOLI IA+MNEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Endoaquolls
TYPICAL PEDON: Tripoli clay loam, on a concave 1 percent slope in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 9 inches; black (N 2/0) clay loam, very dark gray (N 3/0) dry; moderate fine granular structure; friable; few roots; neutral; abrupt smooth boundary.
A1--9 to 14 inches; black (10YR 2/1) clay loam, very dark gray (10YR 3/1) dry; few black (N 2/0) and very dark grayish brown (10YR 3/2) spots; moderate fine granular structure; friable; few roots; neutral; gradual smooth boundary.
A2--14 to 18 inches; very dark gray (10YR 3/1) clay loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to weak fine granular; friable; few roots; many fine pores; common fine faint very dark grayish brown (2.5Y 3/2) redox concentrations; neutral; gradual smooth boundary. (Combined thickness of the A horizons is 14 to 22 inches.)
Bg--18 to 24 inches; very dark grayish brown (2.5Y 3/2) and dark grayish brown (2.5Y 4/2) clay loam, grayish brown (2.5Y 5/2) and light brownish gray (2.5Y 6/2) dry; weak medium subangular blocky structure; friable; common fine and medium pores; few fine faint dark gray (10YR 4/1) redox depletions and common fine prominent yellowish brown (10YR 5/6) redox concentrations; slightly alkaline; gradual smooth boundary. (4 to 6 inches thick)
2Bw1--24 to 29 inches; olive brown (2.5Y 4/4) and light olive brown (2.5Y 5/4) loam; weak medium subangular blocky structure; friable; few roots; common fine and medium pores; indistinct band of pebbles dominantly 1/4 to 1/2 inch in diameter; few stones; few fine distinct dark grayish brown (2.5Y 4/2) redox depletions and common fine distinct yellowish brown (10YR 5/6) redox concentrations; slightly alkaline; gradual smooth boundary.
2Bw2--29 to 38 inches; yellowish brown (10YR 5/6) loam; weak medium prismatic structure parting to moderate fine subangular blocky; firm; few roots; common fine and medium pores; few pebbles; many medium prominent grayish brown (2.5Y 5/2) redox depletions and many medium distinct strong brown (7.5YR 5/8) redox concentrations; slightly alkaline; gradual wavy boundary. (Combined thickness of the 2Bw horizons is 14 to 32 inches.)
2C--38 to 66 inches; yellowish brown (10YR 5/6), strong brown (7.5YR 5/8) and grayish brown (2.5Y 5/2) loam; cleavage faces are grayish brown (2.5Y 5/2); massive; some vertical cleavage; firm; few roots to 47 inches; common fine and medium pores; few 1/8 to 1/4 inch lime concretions; few pebbles; many medium distinct yellowish brown and strong brown redox concentrations; strongly effervescent; moderately alkaline.
TYPE LOCATION: Bremer County, Iowa; about 5 miles west of Tripoli; located about 1,355 feet east and 34 feet north of the southwest corner, sec. 35, T. 93 N., R. 13 W.; USGS Tripoli quad; lat. 42 degrees 49 minutes 12.9 seconds N. and long. 92 degrees 21 minutes 25.6 seconds W., NAD 83.
RANGE IN CHARACTERISTICS: Depth to carbonates is 36 to 48 inches. The depth to glacial till is 18 to 28 inches and a faint to prominent stone line is at the contact of the underlying glacial till. The particle-size control section (weighted average) has 22 to 30 percent clay.
The A horizon has hue of 10YR or is neutral, value of 2 or 3 and chroma of 0 or 1. Textures include clay loam, loam, or silty clay loam with a high content of sand. Clay content is 25 to 32 percent. Rock fragment content is less than 1 percent. Reaction is slightly acid or neutral.
Some pedons have an AB or BA horizon. The AB or BA horizon typically has hue of 10YR to 5Y, value of 3 to 5, and chroma of 1 or 2. The AB or BA horizon is clay loam or silty clay loam with a high content of sand.
The Bg horizon has hues of 10YR to 5Y, value of 3 to 5, and chroma of 1 to 6. Textures include clay loam or loam. Clay content is 22 to 28 percent. Rock fragment content is less than 1 percent except when the lower boundary of this horizon is at the contact of glacial till, where a thin stone line is present. Reaction is neutral or slightly alkaline.
The 2Bw horizon has hues of 10YR to 5Y, value of 3 to 5, and chroma of 1 to 6. Textures include loam, sandy clay loam or clay loam. Clay content is 22 to 28 percent. Rock fragment content ranges from 2 to 10 percent. Reaction is neutral or slightly alkaline.
The 2C horizon has hues of 10YR to 5Y, value of 3 to 5, and chroma of 1 to 6. Textures include loam, sandy clay loam or clay loam. Clay content is 20 to 28 percent. Sand content is 25 to 55 percent. Rock fragment content ranges from 2 to 10 percent. Moist bulk density ranges from 1.65 to 1.75 gm/cc. Reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Clyde, Faxon, Free, Kossuth, Marengo, Reddick, Selma, Selmass, Springerton, Webster, and Wolcott series. Clyde soils formed in 30 to 50 inches of loamy sediments and underlying glacial till. Faxon soils have limestone bedrock within 40 inches. Free soils have more than 15 percent rock fragments in the lower part of the series control section. Kossuth soils have 32 to 35 percent clay in the particle-size control section. Marengo soils formed entirely in glacial till and do not have a lithologic discontinuity. Reddick soils formed in 30 to 50 inches of water-laid sediments and underlying glacial till or lacustrine sediments. Selma soils have less than 15 percent clay in the lower part of the series control section. Selmass soils have more than 80 percent sand in the lower part of the series control section. Springerton soils formed entirely in stratified outwash sediments and do not have a lithologic discontinuity. Webster soils formed entirely in glacial till and do not have a lithologic discontinuity. Walcott soils formed entirely in glacial till and do not have a lithologic discontinuity.
GEOGRAPHIC SETTING: Tripoli soils formed in 18 to 28 inches of moderately fine textured sediments of unknown origin and underlying glacial till of mixed mineralogy. Tripoli soils are nearly level or slightly concave positions on broad upland flats. Slopes range from 0 to 2 percent. Elevation ranges from 650 to 1100 feet. Mean annual temperature is about 45 to 53 degrees F. Mean annual precipitation is about 30 to 35 inches. Frost-free period ranges from 130 to 186 days.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Clyde, Floyd, Kenyon and Readlyn soils. The poorly drained and very poorly drained Clyde soils are on toe slopes and in drainageways. Floyd soils are somewhat poorly drained and are on foot slopes. Kenyon soils are well drained and moderately well drained and are on convex ridges and side slopes. Readlyn soils are somewhat poorly drained and are on slightly convex side slopes.
DRAINAGE AND PERMEABILITY: Poorly drained--seasonal high saturation occurs within depths of 0 to 1.0 feet during April to June in most years and is considered apparent. Permeability is moderate. Runoff is low.
USE AND VEGETATION: Where adequately drained, soils are cultivated. Corn, soybeans and small grains are principal crops. Where undrained, principal use is pasture. Native vegetation is grasses.
DISTRIBUTION AND EXTENT: LRR M, MLRAs 104, 105, 107; moderate extent.
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Bremer County, Iowa, 1965.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon--the zone from the surface to 18 inches (Ap, A1 and A2 horizons); cambic horizon--the zone from 18 to 38 inches (Bg, 2Bw1 and 2Bw2 horizons); aquic suborder based on matrix color and redox concentrations in the zone from 18 to 24 inches (Bg horizon). Cation exchange class is inferred from lab data from similar soils in the surrounding area. Taxonomic version - Second edition, 1999.