LOCATION CROOKSFORD              MN

Established Series
Rev. KDM-TCJ-TWN
01/2011

CROOKSFORD SERIES

The Crooksford series consists of very deep, moderately well drained soils that formed in 50 to 100 centimeters of glacial lacustrine sediments or loess and in the underlying till. These soils are on slightly concave to convex slopes on ground moraines and lake plains. Slope ranges from 1 to 5 percent. Mean annual precipitation is 735 millimeters. Mean annual air temperature is 8 degrees C.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Oxyaquic Hapludolls

TYPICAL PEDON: Crooksford silt loam, on a slightly convex slope of 2 percent, on a ground moraine, in a cultivated field. (Colors are for moist soil unless otherwise noted.)

Ap--0 to 20 centimeters; black (10YR 2/1) silt loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky structure; friable; common fine roots; neutral; abrupt smooth boundary. (15 to 25 centimeters thick)

A--20 to 38 centimeters; very dark brown (10YR 2/2) silt loam, dark grayish brown (10YR 4/2) dry; weak fine subangular blocky structure; friable; common fine roots; neutral; clear smooth boundary. (0 to 25 centimeters thick)

Bw1--38 to 53 centimeters; brown (10YR 4/3) silt loam; weak medium subangular blocky structure; friable; common faint very dark grayish brown (10YR 3/2) organic coats on faces of peds; few fine roots; neutral; clear smooth boundary.

Bw2--53 to 69 centimeters; brown (10YR 4/3) silt loam; weak medium prismatic structure parting to weak medium subangular blocky; friable; few fine roots; neutral; gradual smooth boundary. (Combined thickness of the Bw horizon is 15 to 60 centimeters.)

2Bk1--69 to 84 centimeters; light olive brown (2.5Y 5/4) loam; weak medium prismatic structure parting to weak fine and medium subangular blocky; friable; few fine roots; common light gray (10YR 7/2) fine carbonate masses; about 2 percent gravel; strongly effervescent; moderately alkaline; clear smooth boundary.

2Bk2--84 to 109 centimeters; light olive brown (2.5Y 5/4) loam; weak fine and medium subangular blocky structure; friable; common light gray (10YR 7/2) fine and medium carbonate masses; many medium distinct grayish brown (2.5Y 5/2) iron depletions and few fine and medium distinct yellowish brown (10YR 5/6) iron concentrations; about 8 percent gravel; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the 2Bk horizon is 25 to 50 centimeters.)

2C--109 to 203 centimeters; light olive brown (2.5Y 5/4) loam; massive; friable; carbonates in few light gray (10YR 7/2) medium and coarse soft masses; common medium distinct grayish brown (2.5Y 5/2) iron depletions and common fine distinct yellowish brown (10YR 5/6) iron concentrations; about 6 percent gravel; strongly effervescent; moderately alkaline.

TYPE LOCATION: Major Land resource Area (MLRA) Central Iowa and Minnesota Till Prairies (103), Renville County, Minnesota subset; about 3 miles south of Renville; located about 450 feet north and 450 feet east of the southwest corner of section 20, T. 115 N., R. 36 W.; USGS Vicksburg topographic quadrangle; lat. 44 degrees 44 minutes 59 seconds N. and long. 95 degrees 13 minutes 03 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Thickness of the mollic epipedon--25 to 49 centimeters
Depth to carbonates--40 to 100 centimeters
Depth to till--50 to 100 centimeters
Clay content of the particle-size control section (weighted average)--18 to 30 percent
Sand content of the particle-size control section (weighted average)--less than 15 percent

Ap and A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 or 2
Texture--silt loam, silty clay loam, or loam
Clay content--18 to 30 percent
Sand content--10 to 30 percent
Rock fragment content--0 to 2 percent
Reaction--slightly acid or neutral

Bw horizon:
Hue--10YR or 2.5Y
Value--3 to 5
Chroma--2 to 4
Texture--silt loam or silty clay loam
Clay content--18 to 30 percent
Sand content--less than 15 percent
Rock fragment content--0 to 2 percent
Reaction--neutral or slightly alkaline

Some pedons have a Bk horizon or 2Bw horizon

2Bk horizon:
Hue--10YR or 2.5Y
Value--3 to 5
Chroma--2 to 4
Texture--silt loam, silty clay loam, or loam
Clay content--18 to 30 percent
Sand content--15 to 40 percent
Rock fragment content--2 to 10 percent
Calcium carbonate equivalent--15 to 40 percent
Reaction--slightly alkaline or moderately alkaline

2BC or 2C horizon:
Hue--2.5Y
Value--4 to 6
Chroma--2 to 4
Texture--loam or clay loam
Clay content--18 to 30 percent
Sand content--20 to 45 percent
Rock fragment content--2 to 10 percent
Calcium carbonate equivalent--10 to 20 percent
Reaction--slightly alkaline or moderately alkaline
Moist bulk density--1.30 to 1.55 g/cc

COMPETING SERIES: This is the Sac series.
Sac--have a moist bulk density of 1.6 to 1.8 g/cc in the lower third of the series control section

GEOGRAPHIC SETTING:
Parent material--50 to 100 centimeters of glacial lacustrine sediments or loess and in the underlying till
Landform--slightly concave to convex slopes on ground moraines and lake plains
Slope--1 to 5 percent
Elevation--300 to 400 meters above sea level
Mean annual air temperature--6 to 10 degrees C
Mean annual precipitation--585 to 890 millimeters
Frost-free days--155 to 200 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Leen, Louris, Okoboji, Seaforth and Swanlake soils.
Leen--are on lower landscape positions on footslopes or in drainageways and are frequently saturated at the surface to a depth of 0.45 meter during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Louris--are on lower landscape positions on low knolls and have a frequently saturated zone between depths of 0.45 and 0.75 meter during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Okoboji--are on lower landscape positions in depressions and have a mollic epipedon 60 to 150 centimeters thick
Seaforth--are on landscape positions similar to those of the Crooksford soils and have a sand content that averages 20 to 35 percent in the particle-size control section
Swanlake--are on higher landscape positions on convex slopes and have a rock fragment of 2 to 10 percent throughout the series control section

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well drained--a frequently saturated zone occurs between depths of 0.45 meter and 1.0 meter during the wettest periods of years when precipitation is within one standard deviation of the 30 year mean of annual precipitation
Saturated hydraulic conductivity--1.0 to 10 micrometers per second

USE AND VEGETATION:
Most areas are cultivated. The principal crops are corn, soybeans, and small grains. 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--Western lake section
MLRA--Central Iowa and Minnesota Till Prairies (103)
LRR M; south-central Minnesota
Extent--moderate

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota.

SERIES ESTABLISHED: Renville County, Minnesota, 1995.

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 a depth of 38 centimeters (Ap and A horizons);
cambic horizon--the zone from a depth of 38 to 69 centimeters (Bw1 and Bw2 horizons);
calcic horizon--the zone from a depth of 69 to 109 centimeters (2Bk1 and 2Bk2 horizons);

udic moisture regime.

Oxyaquic subgroup based on saturation above a depth of 1 meter and is supported by the presence of redoximorphic features.

Cation-exchange activity class is inferred from lab data from similar soils in the surrounding area. 1/20/2011-TYPE LOCATION error was corrected.

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

ADDITIONAL DATA:
Laboratory data--Refer to Minnesota Agricultural Experiment Station CFC number 4019.

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National Cooperative Soil Survey
U.S.A.