LOCATION BERTRAM            IA

BERTRAM SERIES

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, mesic Typic Hapludolls

TYPICAL PEDON: Bertram sandy loam, on a north-facing slope of 6 percent, in a cultivated field. (All colors are for moist soil unless otherwise noted.)

Ap--0 to 20 centimeters; very dark brown (10YR 2/2) sandy loam; very dark grayish brown (10YR 3/2) dry; weak fine granular structure; very friable; neutral; abrupt smooth boundary.

A--20 to 43 centimeters; very dark brown (10YR 2/2) and very dark grayish brown (10YR 3/2) sandy loam; very dark grayish brown (10YR 3/2) and dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure, very friable; slightly acid; gradual smooth boundary. (Combined thickness of the A horizon is 25 to 49 centimeters.)

Bw1--43 to 69 centimeters; dark yellowish brown (10YR 4/4) sandy loam, kneaded brown (10YR 4/3); weak coarse subangular blocky structure; very friable; many distinct dark brown (10YR 3/3) organic coats on faces of peds; moderately acid; clear smooth boundary.

Bw2--69 to 76 centimeters; dark yellowish brown (10YR 4/4) sandy loam; weak medium subangular blocky structure; friable; moderately acid; clear smooth boundary. (Combined thickness of the Bw horizon is 20 to 40 centimeters.)

2Bt--76 to 86 centimeters; dark yellowish brown (10YR 4/4) sandy clay loam; moderate fine subangular blocky structure; firm; common distinct clay films on ped faces; moderately acid; abrupt wavy boundary. (3 to 15 centimeters thick)

2C--86 to 91 centimeters; dark yellowish brown (10YR 4/4) gravelly loamy sand; single grain; loose; about 20 percent hard limestone fragments 1 to 3 centimeters in diameter; slightly alkaline. (0 to 10 centimeters thick)

2R--91 centimeters; hard limestone bedrock.

TYPE LOCATION: Major Land Resource Area (MLRA) 104-Eastern Iowa and Minnesota Till Prairies, Linn County, Iowa subset; about 1.5 miles east of Coggon; located about 2,040 feet east and 380 feet north of the southwest corner of section 1, T. 86 N., R. 6 W; USGS Ryan topographic quadrangle; lat. 42 degrees 17 minutes 00 seconds N. and long. 91 degrees 29 minutes 32 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--25 to 49 centimeters
Depth to lithic contact with limestone bedrock--50 to 100 centimeters
Clay content in the particle-size control section (weighted average)--8 to 16 percent
Sand content in the particle-size control section (weighted average)--60 to 80 percent

Ap or A horizon:
Hue--10YR
Value--2 or 3
Chroma--2
Texture--sandy loam, fine sandy loam, or loamy sand
Clay content--2 to 20 percent
Sand content--60 to 80 percent
Reaction--moderately acid to neutral

Bw horizon:
Hue--10YR
Value--3 to 5
Chroma--3 or 4
Texture--sandy loam or fine sandy loam
Clay content--8 to 20 percent
Sand content--60 to 80 percent
Reaction--strongly acid or moderately acid

2Bt horizon:
Hue--10YR
Value--4 or 5
Chroma--4 to 6
Texture--sandy clay loam or clay loam
Clay content--25 to 35 percent
Sand content--40 to 70 percent
Reaction--strongly acid or moderately acid

2C horizon (when present):
Hue--10YR
Value--4 or 5
Chroma--4 to 6
Texture--loamy sand or gravelly loamy sand
Clay content--less than 10 percent
Sand content--75 to 85 percent
Rock fragment content--0 to 35 percent
Reaction--slightly alkaline or moderately alkaline

COMPETING SERIES: These are the Augusta Lake, Aureola, Becker, Bolan, Dickinson, Elrick, Etter, Filley, Flagler, Gardencity, Olin, Ridgeport, Roine, Wadenill, and Zenor series.
None of these series have limestone bedrock within a depth of 100 centimeters

GEOGRAPHIC SETTING:
Parent material--50 to 100 centimeters of oxidized and leached sandy loam eolian material and in the underlying residuum from limestone
Landform--convex summits of interfluves and convex side slopes on dissected till plains
Slope--2 to 14 percent
Elevation--300 to 400 meters above sea level
Mean annual air temperature--7 to 10 degrees C
Mean annual precipitation--735 to 940 millimeters
Frost-free period--160 to 195 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dickinson, Flagler, Marshan, and Rockton soils.
Dickinson--are on landscape positions similar to those of the Bertram soils and do not have limestone bedrock within a depth of 100 centimeters
Flagler--are on lower landscape positions on treads and risers on stream terraces and do not have limestone bedrock within a depth of 100 centimeters
Marshan--are on lower landscape positions in drainageways and have a frequently saturated zone within a depth of 0.3 meter when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Rockton--are on landscape positions similar to those of the Bertram soils and have a clay content that averages 24 to 35 percent in the particle-size control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--well drained and somewhat excessively drained--a saturated zone does not occur within a depth of 1.8 meters when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--10.00 to 100.00 micrometers per second in the eolian material and 1.00 to 10.00 micrometers per second in the residuum and underlying limestone bedrock

USE AND VEGETATION:
The gently sloping areas are commonly cultivated. The principal crops are corn, soybeans, small grains, and legume hay. The steeper slopes are pastured. The native vegetation is big bluestem, little bluestem, switchgrass, and other grasses of the tall grass prairie.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Dissected till plains
MLRA--Eastern Iowa and Minnesota Till Prairies (104)
LRR M; northeastern Iowa
Extent--small

MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota

SERIES ESTABLISHED: Linn County, Iowa, 1970.

Remarks:
Particle-size control section--the zone from a depth of 25 to 91 centimeters;
series control section--the zone from the surface to a depth of 91 centimeters.

Diagnostic horizons and features recognized in this pedon include:
mollic epipedon--the zone from the surface to a depth of 43 centimeters (Ap and A horizons);
cambic horizon--the zone from a depth of 43 centimeters to 86 centimeters (Bw1, Bw2 and 2Bt horizons);
lithic contact--the contact with limestone bedrock at a depth of 91 centimeters;
udic moisture regime.

The upper 0.3 to 1.5 meters of limestone may be significantly fractured and may not be a root restrictive layer.

Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.

Taxonomy version--Keys to Soil Taxonomy, tenth edition, 2006.