LOCATION COGGON IA+MNEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Oxyaquic Hapludalfs
TYPICAL PEDON: Coggon loam, on a slope of about 4 percent, in a wooded pasture. (Colors are for moist soil unless otherwise stated.)
A--0 to 8 centimeters (0 to 3 inches); very dark gray (10YR 3/1) loam, gray (10YR 5/1) dry; moderate fine and very fine granular structure; friable; many roots; slightly acid; clear wavy boundary. [2 to 10 centimeters (1 to 4 inches) thick]
E--8 to 28 centimeters (3 to 11 inches); dark grayish brown (10YR 4/2) loam with a little mixing of very dark gray (10YR 3/1) from the A horizon; moderate thin platy structure; friable; common roots; moderately acid; clear wavy boundary. [5 to 20 centimeters (2 to 8 inches) thick]
BE--28 to 43 centimeters (11 to 17 inches); brown (10YR 5/3) loam with a few fine mixings of yellowish brown (10YR 5/6); moderate fine subangular blocky structure; friable; few roots; about 10 percent rock fragments (2 to 75 millimeters in diameter) concentrated in a stone line 2 to 13 centimeters (1 to 5 inches) thick at the lower boundary of this horizon; strongly acid; clear smooth boundary. [0 to 25 centimeters (0 to 10 inches) thick]
2Bt1--43 to 61 centimeters (17 to 24 inches); yellowish brown (10YR 5/6) loam; moderate fine subangular blocky structure; friable; few roots; few fine pores; few discontinuous distinct dark gray (10YR 4/1) clay films on surfaces along root channels; continuous brown (10YR 5/3) silt and very fine sand on vertical faces of peds; about 4 percent rock fragments (2 to 75 millimeters in diameter); strongly acid; gradual smooth boundary.
2Bt2--61 to 79 centimeters (24 to 31 inches); yellowish brown (10YR 5/6) loam; moderate fine subangular blocky structure; friable; few roots; few fine and medium pores; common discontinuous distinct dark gray (10YR 4/1) clay films on surfaces along root channels; continuous grayish brown (10YR 5/2) silt and very fine sand on vertical faces of peds; few fine soft distinct yellowish red (5YR 4/6) iron accumulations (oxides); few fine prominent grayish brown (2.5Y 5/2) redoximorphic depletions; about 4 percent rock fragments (2 to 75 millimeters in diameter); strongly acid; gradual smooth boundary.
2Bt3--79 to 112 centimeters (31 to 44 inches); yellowish brown (10YR 5/6) and strong brown (7.5YR 5/8) loam; moderate medium prismatic structure parting to moderate medium subangular blocky; firm; common discontinuous distinct dark gray (10YR 4/1) clay films on surfaces along root channels; few discontinuous light brownish gray (10YR 6/2) silt and very fine sand coats on prisms; common fine prominent black (10YR 2/1) concretions (oxides); common fine prominent grayish brown (2.5Y 5/2) redoximorphic depletions; about 4 percent rock fragments (2 to 75 millimeters in diameter); strongly acid; gradual smooth boundary.
2Bt4--112 to 157 centimeters (44 to 62 inches); yellowish brown (10YR 5/6) loam; weak medium subangular blocky structure; firm; common discontinuous distinct dark gray (10YR 4/1) clay films on surfaces along root channels; few discontinuous distinct grayish brown (10YR 5/2) silt and very fine sand on vertical faces of peds; common fine prominent grayish brown (2.5Y 5/2) redoximorphic depletions; about 4 percent rock fragments (2 to 75 millimeters in diameter); strongly acid; gradual smooth boundary. [Combined thickness of the 2Bt horizon is 97 to 122 centimeters (38 to 48 inches).]
2BC--157 to 203 centimeters (62 to 80 inches); yellowish brown (10YR 5/6) loam; moderate coarse and extremely coarse prismatic structure dissected by few oblique fractures; very firm; many coarse prominent light brownish gray (2.5Y 6/2) redoximorphic depletions; about 4 percent rock fragments (2 to 75 millimeters in diameter); neutral.
TYPE LOCATION: Major Land Resource Area (MLRA) 104-Eastern Iowa and Minnesota Till Prairies; Bremer County, Iowa subset; about 3 1/2 miles north and 1 mile east of Tripoli; about 283 meters (930 feet) west and 221 meters (725 feet) south of the northeast corner of section 22, T. 93 N., R. 12 W.; USGS Sumner SW quadrangle; lat 42 degrees 51 minutes 36 seconds N. and long. 92 degrees 14 minutes 33 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to glacial till--36 to 56 centimeters (14 to 22 inches)
Depth to carbonates--greater than 203 centimeters (80 inches)
Content of clay in the particle-size control section (weighted average)--20 to 28 percent
Content of sand in the particle-size control section (weighted average)--25 to 45 percent
Special feature--some pedons have a stone line or thin layer, 2 to 13 centimeters (1 to 5 inches) thick of gravelly and sandy materials at the base of the silty or loamy sediments
Ap or A horizon:
Hue--10YR
Value--3 or 4
Chroma--1 to 3
Texture--loam or silt loam
Clay content--18 to 24 percent
Sand content--20 to 50 percent
Reaction--strongly acid to neutral
Rock fragment content--1 to 10 percent
Special features--when mixed to a depth of 18 centimeters (7 inches), matrix value is 4 or more, moist, 6 or more, dry
E horizon:
Hue--10YR
Value--4 or 5
Chroma--2 or 3
Texture--loam or silt loam
Clay content--18 to 24 percent
Sand content--20 to 50 percent
Reaction--strongly acid to neutral
Rock fragment content--1 to 10 percent
BE horizon:
Hue--10YR
Value--4 or 5
Chroma--3 to 6
Texture--loam or silt loam
Clay content--18 to 24 percent
Sand content--20 to 50 percent
Reaction--strongly acid to neutral
Rock fragment content--1 to 10 percent
2Bt horizon:
Hue--7.5YR or 10YR
Value--4 or 5
Chroma--3 to 8
Texture--loam, clay loam, or sandy clay loam
Clay content--20 to 28 percent
Sand content--25 to 45 percent
Reaction--very strongly acid to moderately acid
Rock fragment content--2 to 15 percent
2BC horizon:
Hue--10YR or 2.5Y
Value--5 or 6
Chroma--2 to 6
Texture--loam
Clay content--18 to 27 percent, mean of 22 percent
Sand content--35 to 50 percent, mean of 44 percent
Reaction--slightly acid to moderately alkaline
Rock fragment content--2 to 15 percent
Moist bulk density--1.75 g/cc to 1.90 g/cc
COMPETING SERIES: These are the
Beech,
Blakeslee,
Dormont,
Nessel,
Richland, and
Summitville series.
Beech--average 15 to 35 percent rock fragments in the particle-size control section
Blakeslee--have a rock fragment content of 25 to 80 percent in the lower third of the series control section
Dormont--have 5 to 50 percent siltstone, shale or sandstone rock fragments in the lower third of the series control section
Nessel--do not have a lithologic discontinuity within the series control section and have carbonates within depths of 76 to 122 centimeters (30 to 48 inches)
Richland--have more than 20 percent rock fragments in the middle third of the series control section
Summitville--have up to 35 percent flat fragments of siltstone and sandstone in the upper third of the series control section
GEOGRAPHIC SETTING:
Parent material--36 to 56 centimeters (14 to 22 inches) of silty or loamy sediments and the underlying glacial till
Landform--interfluves and side slopes on dissected till plains
Slopes--1 to 9 percent
Elevation--213 to 427 meters (700 to 1400 feet) above sea level
Mean annual air temperature--7 to 10 degrees C (45 to 50 degrees F)
Mean annual precipitation--76 to 86 centimeters (30 to 34 inches)
Frost-free period--150 to 180 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Bassett,
Clyde,
Oran, and
Tripoli soils.
Bassett--are on similar landscape positions as the Coggon soils and have layers that when mixed to a depth of 18 centimeters (7 inches), have a matrix value of 3 or less, moist, 5 or less, dry
Clyde--are at lower elevations in flat to concave drainageways, have a frequently saturated zone within a depth of 0.3 meter (0 to 1 foot) in normal years and have glacial till with moist bulk density of 1.75 g/cc to 1.90 g/cc within depths of 76 to 127 centimeters (30 to 50 inches)
Oran--are at lower elevations on interfluves, have an ochric epipedon 15 to 43 centimeters (6 to 17 inches) thick, have glacial till with moist bulk density of 1.75 g/cc to 1.90 g/cc within depths of 36 to 61 centimeters (14 to 24 inches), and have a frequently saturated zone within depths of 0.3 to 1.1 meters (1.0 to 3.5 feet) in normal years
Tripoli--are at lower elevations in flat to concave drainageways, have a frequently saturated zone within a depth of 0.3 meter (0 to 1 foot) in normal years, and have glacial till with moist bulk density of 1.75 g/cc to 1.90 g/cc within depths of 46 to 71 centimeters (18 to 28 inches)
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs within depths of 0.6 to 1.1 meters (2.0 to 3.5 feet) during April to June in normal years and both perched and apparent saturation can occur on this soil based on the season and intensity of rainfall during a given period of time
Saturated hydraulic conductivity--moderately high in the silty or loamy sediments and low or moderately low in the glacial till
Surface runoff potential--low or medium
USE AND VEGETATION:
Many areas are pastured or wooded. Some areas are cultivated. The principal crops are corn, small grains, soybeans, and hay. The native vegetation is deciduous trees, dominantly oak and hickory.
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)
LRR M; northeast Iowa and southeast Minnesota
Extent--small
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 43 to 93 centimeters (17 to 37 inches) (2Bt1, 2Bt2, and 2Bt3 horizons);
series control section--the zone from the surface to a depth of 157 centimeters (62 inches) (A, E, BE, 2Bt1, 2Bt2, 2Bt3, and 2Bt4 horizons).
Diagnostic horizons and features recognized in this pedon:
ochric epipedon--the zone from the surface to a depth of 28 centimeters (0 to 11 inches) (A and E horizons);
argillic horizon--the zone from a depth of 43 to 157 centimeters (17 to 62 inches) (2Bt1,2Bt2, 2Bt3, and 2Bt4 horizons);
udic moisture regime.
Some pedons have vertical seams or wedges of sand or loamy sand about 5 to 15 centimeters (2 to 6 inches) wide and about 0.9 to 1.2 meters (3 to 4 feet) deep extending downward from the stone line into the glacial till.
Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Oxyaquic subgroup based on a zone of saturation within 100 centimeters (39 inches) for 20 or more consecutive days or 30 or more cumulative days in normal years.
Taxonomy version--Keys to Soil Taxonomy, ninth edition, 2003.