LOCATION BURKHARDT          WI+IA IL MN

BURKHARDT SERIES

TAXONOMIC CLASS: Sandy, mixed, mesic Typic Hapludolls

TYPICAL PEDON: Burkhardt sandy loam, on a 1 percent slope, in a cultivated field, at an elevation of about 242 meters above sea level. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 25 centimeters; very dark brown (10YR 2/2) sandy loam, grayish brown (10YR 5/2) dry; weak medium subangular blocky structure; friable; many fine fibrous roots; slightly acid; abrupt smooth boundary. (17 to 26 centimeters thick)

Bt--25 to 43 centimeters; dark brown (7.5YR 3/2) sandy loam; moderate fine subangular blocky structure; friable; few faint clay films on faces of peds and clay bridges between sand grains; amount of clay is similar to horizon above; few fine fibrous roots; moderately acid; clear smooth boundary. (9 to 34 centimeters thick)

2BC--43 to 48 centimeters; brown (7.5YR 4/4) loamy sand; weak medium subangular blocky structure; very friable; dark-colored stains from organic matter on the faces of some peds; about 12 percent gravel; moderately acid; clear smooth boundary. (0 to 26 centimeters thick)

2C1--48 to 74 centimeters; strong brown (7.5YR 5/6) and brown (7.5YR 4/4) stratified sand and gravelly coarse sand; single grain; loose; about 20 percent gravel as an average; moderately acid; gradual smooth boundary.

2C2--74 to 152 centimeters; strong brown (7.5YR 5/6) stratified sand and gravelly coarse sand; single grain; loose; about 25 percent gravel as an average; moderately acid.

TYPE LOCATION: Major Land Resource Area (MLRA) 104-Eastern Iowa and Minnesota Till Prairies, Pepin County, Wisconsin subset; about 1/2 mile south of Arkansas; located about 300 feet east and 100 feet north of the southwest corner of section 24, T. 25 N., R. 14 W.; USGS Arkansaw topographic quadrangle; lat. 44 degrees 37 minutes 34 seconds N. and long. 92 degrees 01 minute 58 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--17 to 49 centimeters
Depth to sandy outwash--25 to 50 centimeters
Depth to carbonates--more than 100 centimeters
Clay content in the particle-size control section (weighted average)--5 to 15 percent
Sand content in the particle-size control section (weighted average)--75 to 95 percent

A or Ap horizon:
Hue--7.5YR or 10YR
Value--2 or 3
Chroma--1 to 3
Texture--sandy loam, loam, gravelly sandy loam, or gravelly loam
Clay content--5 to 22 percent
Sand content--45 to 70 percent
Rock fragment content--0 to 35 percent, gravel and 0 to 5 percent, cobbles
Reaction--strongly acid to neutral

AB horizon (when present):
Hue--7.5YR or 10YR
Value--3 or 4
Chroma--2 or 3
Texture--sandy loam, loam, gravelly sandy loam, or gravelly loam
Clay content--5 to 22 percent
Sand content--45 to 70 percent
Rock fragment content--0 to 35 percent, gravel and 0 to 5 percent, cobbles
Reaction--strongly acid to neutral

Bt or Bw horizon:
Hue--7.5YR or 10YR
Value--3 or 4
Chroma--2 to 4
Texture--sandy loam, loam, gravelly sandy loam, or gravelly loam
Clay content--5 to 18 percent
Sand content--35 to 95 percent
Rock fragment content--0 to 35 percent, gravel and 0 to 5 percent, cobbles
Reaction--strongly acid to neutral

The Bt horizon does not meet the requirements for an argillic horizon

2Bt and 2BC horizon (when present):
Hue--7.5YR or 10YR
Value--3 or 4
Chroma--4 to 6
Texture--sand, coarse sand, loamy sand, loamy coarse sand, the gravelly or very gravelly analogs of these textures, or is stratified with these textures
Clay content--2 to 15 percent
Sand content--75 to 95 percent
Rock fragment content--5 to 35 percent, gravel and 0 to 5 percent, cobbles, some individual strata have 1 to 60 percent gravel
Reaction--strongly acid to neutral

2C horizon:
Hue--7.5YR or 10YR
Value--4 to 6
Chroma--4 to 6
Texture-- stratified sand, coarse sand, gravelly sand, gravelly coarse sand, very gravelly sand, or very gravelly coarse sand
Clay content--0 to 10 percent
Sand content--75 to 100 percent
Rock fragment content--5 to 35 percent, gravel and 0 to 5 percent, cobbles, some individual strata have 1 to 60 percent gravel
Reaction--moderately acid to slightly acid

In MLRA 104 and the western part of MLRA 105, the reaction is slightly acid to slightly alkaline with small amounts of calcium carbonate in the sandy outwash

COMPETING SERIES: These are the Buckney, Dickman, Estherville, Mishawaka, Pilot Grove, and Round lake series.
Buckney--do not have rock fragments in the series control section
Dickman--have a rock fragment content of less than 15 percent in the series control section
Estherville--have carbonates within a depth of 100 centimeters
Mishawaka--have a rock fragment content of less than 15 percent in the lower third of the series control section
Pilot Grove--have a sand content of less than 75 percent in the lower third of the series control section
Round lake--have a sand content of less than 75 percent in the lower third of the series control section and have a frequently saturated zone within a depth of 1.8 meters during the wettest periods of normal years

GEOGRAPHIC SETTING:
Parent material--25 to 50 centimeters of loamy alluvium and in the underlying sandy outwash
Landform--outwash plains, outwash terraces, and valley trains
Slope--0 to 30 percent
Elevation--210 to 335 meters above mean sea level
Mean annual air temperature--8 to 11 degrees C
Mean annual precipitation--630 to 870 millimeters
Frost-free period--135 to 165 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Dakota, Finchford, Plainfield, and Rasset soils.
Dakota--are in landscape positions similar to those of Burkhardt soils and have a clay content that averages more than 18 percent in the upper half of the particle-size control section
Finchford--are in landscape positions similar to those of Burkhardt soils and do not have a cambic horizon
Plainfield--are in similar landscape positions or are on terrace risers and do not have a mollic epipedon
Rasset--are in landscape positions similar to those of Burkhardt soils and have an argillic horizon

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--somewhat excessively drained--a frequently saturated zone does not occur within a depth of 1.8 meters during the wettest periods of normal years
Saturated hydraulic conductivity--1.00 to 42.00 micrometers per second in the loamy alluvium and 42.00 to 705.00 micrometers per second in the sandy outwash
Surface runoff potential--negligible to medium

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, small grain, and hay. Some areas are irrigated. The native vegetation is big bluestem, little bluestem, switchgrass, other grasses of the tall grass prairie or a combination of prairie grasses and bur oaks.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic sections--Western lake section, Dissected till plains, Wisconsin driftless section, and Till plains
MLRAs--Wisconsin and Minnesota Thin Loess and Till (90),
Wisconsin and Minnesota Sandy Outwash (91),
Eastern Iowa and Minnesota Till Prairies (104),
Northern Mississippi Valley Loess Hills (105), and
Illinois and Iowa Deep Loess and Drift (108)
LRR M; West-central Wisconsin, central and eastern Minnesota, northwest Illinois, and northeastern Iowa
Extent--moderate

MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota

SERIES ESTABLISHED: Washington County, Minnesota, 1941.

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 of the soil to a depth of 25 centimeters (Ap horizon);
cambic horizon--the zone from a depth of 25 to 43 centimeters (Bt horizon);
udic moisture regime.

Lab data indicates that Burkhardt soils have base saturation of 50 percent or more (by NH4OAc) in all horizons between the mineral soil surface and a depth of 180 cm. However, it is suspected that the very low CEC in the sandy outwash results in drastic changes in base saturation with the addition of a few bases from fertilization. These soils may be Inceptisols in their natural state.

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

ADDITIONAL DATA:
Laboratory data--National Soil Survey Laboratory, Lincoln, Nebraska - 5 pedons (http://ssldata.nrcs.usda.gov/).