LOCATION TRIPOLI IA+MN
Established Series
Rev. RID-ECS-RJB
06/2015
TRIPOLI SERIES
The Tripoli series consists of very deep, poorly drained soils that formed in 30 to 70 centimeters of loamy sediments and the underlying till. Tripoli soils are on nearly level or slightly concave positions on dissected till plains of low relief on the Iowan Erosion Surface. Slope ranges from 0 to 2 percent. Mean annual precipitation is about 850 millimeters. Mean annual air temperature is about 8 degrees C.
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Typic Endoaquolls
TYPICAL PEDON: Tripoli clay loam, on a concave slope of 1 percent, in a cultivated field. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 23 centimeters; 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--23 to 36 centimeters; 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) mixings; moderate fine granular structure; friable; few roots; neutral; gradual smooth boundary.
A2--36 to 46 centimeters; 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) redoximorphic concentrations; neutral; gradual smooth boundary. (Combined thickness of the A horizon is 36 to 60 centimeters.)
Bg--46 to 58 centimeters; dark grayish brown (2.5Y 4/2) clay loam, 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) redoximorphic depletions; common fine prominent yellowish brown (10YR 5/6) redoximorphic concentrations; slightly alkaline; gradual smooth boundary. (10 to 15 centimeters thick)
2Bw1--58 to 74 centimeters; 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; few fine distinct dark grayish brown (2.5Y 4/2) redoximorphic depletions; common fine distinct yellowish brown (10YR 5/6) redoximorphic concentrations; indistinct band of pebbles dominantly .5 to 1.5 centimeters in diameter; few stones; slightly effervescent; slightly alkaline; gradual smooth boundary.
2Bw2--74 to 97 centimeters; yellowish brown (10YR 5/6) loam; weak medium prismatic structure parting to moderate fine subangular blocky; firm; few roots; common fine and medium pores; many medium prominent grayish brown (2.5Y 5/2) redoximorphic depletions; many medium distinct strong brown (7.5YR 5/8) redoximorphic concentrations; about 4 percent rock fragments; slightly effervescent; slightly alkaline; gradual wavy boundary. (Combined thickness of the 2Bw horizon is 35 to 80 centimeters.)
2BC1--97 to 168 centimeters; yellowish brown (10YR 5/6), strong brown (7.5YR 5/8), and grayish brown (2.5Y 5/2) loam; faces of peds are grayish brown (2.5Y 5/2); weak very coarse prismatic structure; firm; few roots to 119 centimeters; common fine and medium pores; few lime concretions; many medium distinct yellowish brown (10YR 5/8) and many medium faint strong brown (7.5YR 5/6) redoximorphic concentrations; about 4 percent rock fragments; strongly effervescent; moderately alkaline; gradual wavy boundary.
2BC2--168 to 200 centimeters; yellowish brown (10YR 5/4), strong brown (7.5YR 5/6), and grayish brown (2.5Y 5/2) loam; faces of peds are grayish brown (2.5Y 5/2); weak very coarse prismatic structure; firm; common fine and medium pores; few lime concretions; many medium distinct yellowish brown (10YR 5/6) and many medium prominent strong brown (7.5YR 5/8) redoximorphic concentrations; about 4 percent rock fragments; strongly effervescent; moderately alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 104-Eastern Iowa and Minnesota Till Prairies, Bremer County, Iowa subset; about 5 miles west of Tripoli; located about 1,355 feet east and 34 feet north of the southwest corner of section 35, T. 93 N., R. 13 W.; USGS Tripoli topographic quadrangle; lat. 42 degrees 49 minutes 6.7 seconds N. and long. 92 degrees 21 minutes 7.97 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to carbonates--90 to 122 centimeters
Depth to till--30 to 75 centimeters
Clay content in the particle-size control section (weighted average)--22 to 30 percent
Sand content in the particle-size control section (weighted average)--30 to 50 percent
Special feature--some pedons have a stone line or thin layer, 2 to 13 centimeters thick, of gravelly and sandy materials at the base of the loamy sediments
Ap or A horizon:
Hue--10YR or neutral
Value--2 or 3
Chroma--0 or 1
Texture--clay loam, loam, or silty clay loam with a high content of sand
Clay content--25 to 32 percent
Sand content--15 to 40 percent
Rock fragment content--less than 1 percent
Reaction--slightly acid or neutral
AB or BA horizon:
Hue--10YR to 5Y
Value--3 to 5
Chroma--1 or 2
Texture--clay loam or silty clay loam with a high content of sand
Clay content--27 to 35 percent
Sand content--15 to 45 percent
Rock fragment content--less than 1 percent
Reaction--slightly acid or neutral
Bg horizon:
Hue--10YR to 5Y
Value--4 or 5
Chroma--1 or 2
Texture--clay loam or loam
Clay content--22 to 28 percent
Sand content--20 to 40 percent
Rock fragment content--less than 1 percent, except when the lower boundary of this horizon is at the contact of till, where a thin stone line may be present
Reaction--slightly acid to slightly alkaline
2Bw or 2Bg horizon:
Hue--10YR to 5Y
Value--4 or 5
Chroma--1 to 6
Texture--loam, sandy clay loam, or clay loam
Clay content--22 to 28 percent
Sand content--30 to 50 percent
Rock fragment content--2 to 10 percent
Reaction--slightly acid to slightly alkaline
2BC or 2BCg horizon:
Hue--10YR to 5Y
Value--4 to 6
Chroma--1 to 8
Texture--loam
Clay content--18 to 27 percent, mean of 22 percent
Sand content--35 to 55 percent, mean of 44 percent
Rock fragment content--2 to 12 percent
Reaction--slightly acid to moderately alkaline
Moist bulk density--1.75 to 1.90 g/cc
COMPETING SERIES: These are the
Clyde,
Faxon,
Kossuth,
Letri,
Marengo,
Mound Creek,
Reddick,
Selma,
Selmass,
Webster, and
Wolcott series.
Clyde--have till with a moist bulk density of 1.75 g/cc at depths greater than 75 centimeters
Faxon--have a lithic contact with limestone within a depth of 100 centimeters
Kossuth--have a clay content that averages 32 to 35 percent in the particle-size control section
Letri--have carbonates within a depth of 75 centimeters
Marengo--have a rock fragment content of 2 to 14 percent in the upper third of the series control section
Mound Creek--has a lithic contact with quartzite within a depth of 100 centimeters
Reddick--have a sand content of less than 20 percent in the lower third of the series control section
Selma--have a clay content of 3 to 15 percent in the lower third of the series control section
Selmass--have a sand content of more than 80 percent in the lower third of the series control section
Webster--have a moist bulk density of less than 1.75 g/cc in the lower third of the series control section
Wolcott--have a moist bulk density of less than 1.75 g/cc in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--30 to 75 centimeters of loamy sediments and the underlying till
Landform--nearly level or slightly concave positions on dissected till plains of low relief on the Iowan Erosion Surface
Slope--0 to 2 percent
Elevation--200 to 400 meters above sea level
Mean annual air temperature--6 to 10 degrees C
Mean annual precipitation--735 to 965 millimeters
Frost-free period--145 to 205 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Clyde,
Floyd,
Kenyon and
Readlyn soils.
Clyde--are on lower landscape positions in swales and concave drainageways and have till with a moist bulk density of 1.75 g/cc at depths greater than 75 centimeters
Floyd--are on higher landscape positions adjacent to drainageways, have a mollic epipedon 40 to 60 centimeters thick and have a frequently saturated zone between depths of 0.3 and 1 meter during the wettest portions of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Kenyon--are on higher landscape positions on interfluves and side slopes and have a frequently saturated zone between depths of 1.0 and 1.8 meter during the wettest portions of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Readlyn--are on higher landscape positions on convex side slopes and have a frequently saturated zone between depths of 0.3 and 1 meter during the wettest portions of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained--these soils are frequently saturated at the soil surface to a depth of 0.3 meter during the wettest periods portions of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation, both perched and apparent saturation can occur on this soil based on precipitation frequency and intensity during a given period of time
Saturated hydraulic conductivity--1.0 to 10.0 micrometers per second in the loamy sediments and 0.01 to 1.0 micrometers per second in the underlying till
USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grains, and legume hay. The native vegetative cover is a herbaceous wetland community commonly inhabited with Bluejoint Grasses, Fowl Bluegrasses, Green Muhlies, Fox Sedges, Field Sedges, Dudleys Rushes, Torreys Rushes, Swamp Milkweeds, False Sneezeweeds, False Asters, New England Asters, White Panicled Asters, and Wild Mints.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Dissected till plains and Wisconsin driftless section
MLRAs--Eastern Iowa and Minnesota Till Prairies (104) and Northern Mississippi Valley Loess Hills (105)
Local physiographic area--Iowa Erosion Surface
LRR M; northeastern Iowa and southeastern Minnesota
Extent--large
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana
SERIES ESTABLISHED: Bremer County, Iowa, 1965.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters;
series control section--the zone from the surface to a depth of 150 centimeters.
Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to 46 centimeters (Ap, A1 and A2 horizons);
cambic horizon--the zone from 46 to 97 centimeters (Bg, 2Bw1, and 2Bw2 horizons);
aquic suborder based on matrix color and redoximorphic concentrations in the zone from a depth of 46 to 58 centimeters (Bg horizon).
Some pedons have vertical seams or wedges of sand or loamy sand about 5 to 30 centimeters wide and about 0.9 to 1.2 meters deep extending downward from the stone line into the till.
Cation exchange class is inferred from lab data from similar soils in the surrounding area.
Taxonomic version--Keys to Soil Taxonomy, tenth edition, 2006.
National Cooperative Soil Survey
U.S.A.