LOCATION DORCHESTER IA+IL MN WIEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, calcareous, mesic Typic Udifluvents
TYPICAL PEDON: Dorchester silt loam, on a slope of 1 percent, in a cultivated field, at an elevation of about 235 meters. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 20 centimeters; dark grayish brown (10YR 4/2) silt loam, light brownish gray (10YR 6/2) dry; massive but tending to be platy due to stratification; friable; slightly effervescent; slightly alkaline; clear smooth boundary. (13 to 24 centimeters thick)
C--20 to 79 centimeters; stratified dark grayish brown (10YR 4/2), grayish brown (10YR 5/2) and brown (10YR 5/3) silt loam; massive with weak thin alluvial stratification; friable; common fine distinct brown (7.5YR 4/4) concretions (iron oxides); slightly effervescent; slightly alkaline; abrupt wavy boundary. (35 to 95 centimeters thick)
Ab1--79 to 124 centimeters; black (10YR 2/1) silt loam; weak fine granular structure; friable; neutral; gradual smooth boundary.
Ab2--124 to 152 centimeters; very dark brown (10YR 2/2) silt loam; black (10YR 2/1) coats on faces of peds; weak fine subangular blocky structure; friable; neutral.
TYPE LOCATION: Major Land Resource Area (MLRA) 105-Northern Mississippi Valley Loess Hills; Clayton County, Iowa subset; about 4 miles north and 2 miles east of Edgewood; located about 660 feet east and 75 feet north of the southwest corner of section 8, T. 91 N., R. 4 W.; USGS Garber topographic quadrangle; lat. 42 degrees 42 minutes 13 seconds N. and long. 91 degrees 20 minutes 46 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to carbonates--0 to 25 centimeters
Depth to buried horizons--50 to 114 centimeters
Content of clay in the particle-size control section (weighted average)--18 to 24 percent
Content of sand in the particle-size control section (weighted average)--5 to 25 percent, dominantly very fine sand
Ap or A horizon:
Hue--10YR
Value--3 or 4
Chroma--2 or 3
Texture--silt loam, loam, or silty clay loam
Clay content--10 to 30 percent
Sand content--10 to 40 percent
Reaction--slightly alkaline or moderately alkaline
C horizon:
Hue--10YR
Value--3 to 6
Chroma1 to 3
Texture--silt loam, some pedons contain thin strata of loam
Clay content--18 to 24 percent
Sand content5 to 30 percent
Reaction--slightly alkaline or moderately alkaline
Ab horizon:
Hue--10YR
Value2 or 3
Chroma--1 to 3
Texture--clay loam, silt loam or silty clay loam
Clay content--18 to 30 percent
Sand content--10 to 40 percent
Reactionneutral to moderately alkaline
Some pedons have cobbly materials below a depth of 150 centimeters
Some pedons have sandy sediments below a depth of 150 centimeters
COMPETING SERIES: There are no competing series.
GEOGRAPHIC SETTING:
Parent material--recent, calcareous, stratified alluvium
Landform--narrow flood plains of small streams that have limestone bluffs on the nearby slopes
Slope--0 to 5 percent
Elevation--213 to 457 meters above sea level
Mean annual air temperature--7 to 11 degrees C
Mean annual precipitation--750 to 870 millimeters
Frost-free period--145 to 175 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Arenzville,
Caneek,
Colo,
Ossian, and
Volney soils.
Arenzville--are on similar landscape positions as the Dorchester soils and have a clay content that averages 10 to 18 percent in the particle-size control section
Caneek--are on slightly lower landscape positions and are frequently saturated at the soil surface during the wettest periods of normal years
Colo--are on slightly lower landscape positions, have a mollic epipedon more than 91 centimeters thick, do not have carbonates within a depth of 150 centimeters, and are frequently saturated at the soil surface during the wettest periods of normal years
Ossian--are on slightly lower landscape positions, have a mollic epipedon 40 to 60 centimeters thick, do not have carbonates within a depth of 102 centimeters, and are frequently saturated at the soil surface during the wettest periods of normal years
Volneyare on slightly higher landscape positions, have a mollic epipedon 60 to 90 centimeters thick and have a rock fragment content of 15 to 90 percent in the series control section
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--difficult to assess because of the youthful profile but is considered to be well drained and moderately well drained--a frequently saturated zone does not occur within a depth of 1 meter during April to June in normal years
Saturated hydraulic conductivity--4.23 to 14.11 micrometers per second (moderately high)
Surface runoff potential--negligible to low
Flooding--rarely to frequently flooded for very brief to brief duration during the months of February to November from precipitation events and snowmelt
USE AND VEGETATION:
Most areas are pastured. Where cultivated, the principal crops are corn, soybeans, small grains, and legume hay. The native vegetation is grass with scattered deciduous trees; however, parent materials are so recent that these soils are not influenced by vegetation.
DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sectionsEastern lake section, Western lake section, Wisconsin driftless section and Dissected till plains
MLRAsSouthern Wisconsin and Northern Illinois Drift Plain (95B), Central Iowa and Minnesota Till Prairies (103), Northern Mississippi Valley Loess Hills (105) and Illinois and Iowa Deep Loess and Drift (108)
LRRs K and M; northeastern Iowa, Minnesota, Wisconsin, and Illinois
Extent--moderate
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Nicollet County, Minnesota, 1949.
REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (C and Ab1 horizons);
series control section--the zone from the surface to a depth of 150 centimeters (Ap, C, Ab1 and Ab2 horizons).
Diagnostic horizons and features recognized in this pedon include:
ochric epipedon - the zone from the soil surface to a depth of 20 centimeters (Ap horizon);
calcareous family class--carbonates present in all parts between depths of 25 to 50 centimeters;
udic moisture regime.
Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area.
Taxonomy version--Keys to Soil Taxonomy, ninth edition, 2003.