LOCATION CROOKSFORD MNEstablished Series
TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Oxyaquic Hapludolls
TYPICAL PEDON: Crooksford silt loam with 2 percent slightly convex slope on a ground moraine in a cultivated field. (Colors are for moist soil unless otherwise noted.)
Ap--0 to 8 inches; 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 (6 to 10 inches thick)
A--8 to 15 inches; 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 10 inches thick)
Bw1--15 to 21 inches; 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--21 to 27 inches; 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 horizons is 6 to 24 inches)
2Bk1--27 to 33 inches; light olive brown (2.5Y 5/4) loam; weak medium prismatic structure parting to weak fine and medium subangular blocky; friable; few fine roots; about 2 percent gravel; common light gray (10YR 7/2) fine carbonate masses; strongly effervescent; moderately alkaline; clear smooth boundary.
2Bk2--33 to 43 inches; light olive brown (2.5Y 5/4) loam; weak fine and medium subangular blocky structure; friable; many medium distinct grayish brown (2.5Y 5/2) Fe depletions and few fine and medium distinct yellowish brown (10YR 5/6) Fe concentrations; about 8 percent gravel; common light gray (10YR 7/2) fine and medium carbonate masses; strongly effervescent; moderately alkaline; gradual smooth boundary. (Combined thickness of the 2Bk horizon is 10 to 20 inches)
2C--43 to 80 inches; light olive brown (2.5Y 5/4) loam; massive; friable; common medium distinct grayish brown (2.5Y 5/2) Fe depletions and common fine distinct yellowish brown (10YR 5/6) Fe concentrations; about 6 percent gravel; carbonates in few light gray (10YR 7/2) medium and coarse soft masses; strongly effervescent; moderately alkaline.
TYPE LOCATION: Renville County, Minnesota; about 3 miles south of Renville; 450 feet north and 200 feet east of the southwest corner of sec. 20, T. 115 N., R. 36 W. USGS Vicksburg quadrangle, latitude 44 degrees 44 minutes 50 seconds N. and longitude 95 degrees 13 minutes 04 seconds W., NAD 27.
RANGE IN CHARACTERISTICS: The mollic epipedon is 10 to 24 inches thick. The depth to free calcium carbonates range from 16 to 40 inches. The silty mantle is 25 to 40 inches thick. It typically does not have coarse fragments but has as much as 2 percent, by volume, in some pedons. The underlying glacial till has 2 to 10 percent coarse fragments by volume. The control section has 18 to 30 percent clay and less than 15 percent fine sand or coarser.
The A and Ap horizons have hue of 10YR, value of 2 or 3 and chroma of 1 or 2. They are typically silt loam or silty clay loam. It is slightly acid or neutral.
The upper Bw horizon has hue of 10YR, value of 3 through 5 and chroma of 3 or 4 and the lower Bw horizon has hue of 2.5Y or 10YR, value of 4 or 5 and chroma of 2 through 4. It has mottles in the lower part in some pedons. It typically is silt loam but ranges to silty clay loam in some subhorizons. It is neutral or slightly alkaline.
Some pedons have a Bk horizon or 2Bw horizon.
The 2Bk horizon has hue of 10YR or 2.5Y, value of 3 through 5 and chroma of 2 through 4. Mottles with chroma of 2 or less typically occur in this horizon. It typically is silt loam, but includes silty clay loam and subhorizons of loam high in content of very fine sand. It has 15 to 40 percent calcium carbonate equivalent. The reaction is moderately alkaline or slightly alkaline.
The 2C horizon has value of 4 through 6 and chroma of 2 through 4. It is loam or clay loam. It has 10 to 20 percent calcium carbonate equivalent. The reaction is slightly alkaline or moderately alkaline.
COMPETING SERIES: These are the Nira and Sac sereis. Nira soils do not have free carbonates in the lower two thirds of the series control section. Sac soils have moist bulk density of 1.6 to 1.8 g/cc in the lower third of the series control section.
GEOGRAPHIC SETTING: These soils have slightly concave to convex slopes with gradient of 1 to 5 percent on ground moraines and lake plains. They formed in a silty mantle of glacial lacustrine sediments or loess that is 24 to 40 inches and the underlying loamy calcareous glacial till. These sediments are Late Wisconsinan age. Mean annual precipitation ranges from 22 to 26 inches, and mean annual air temperature from 45 to 48 degrees F. Frost free days range from 120 to 160. Elevation above sea level is 1000 to 1500 feet.
GEOGRAPHICALLY ASSOCIATED SOILS: These are the Leen, Louris, Okoboji, Seaforth and Swanlake soils. The poorly drained Leen soils are on adjacent footslopes or in drainageways. The somewhat poorly drained Louris soils are on low knolls. Leen and Louris soils have a silty mantle similar in thickness to the Crooksford soils. The very poorly drained Okoboji soils are in depressions. The moderately well drained Seaforth soils are on low, convex knobs and ridges. The well drained Swanlake soils are on higher positions. Seaforth and Swanlake soils lack an upper mantle.
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY: These soils are moderately well drained. Surface runoff is moderately low to moderately high. Saturated hydraulic conductivity, as measured in inches per hour, is .6 to 2. Depth to a seasonal high saturation is high as 20 inches at some time during the months of March to July and October and November.
USE AND VEGETATION: These soils are mostly in cropland. Principal crops are corn, soybeans, and small grains. Native vegetation is tall grass prairie.
DISTRIBUTION AND EXTENT: South Central Minnesota; moderately extensive.
MLRA OFFICE RESPONSIBLE: St. Paul, Minnesota
SERIES ESTABLISHED: Renville County, Minnesota, 1995.
REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to 15 inches (Ap and A horizons); cambic horizon - the zone from 15 to 27 inches (Bw horizons); calcic horizon - the zone from 27 to 43 inches (Bk horizons);
ADDITIONAL DATA: For data from a representative pedon refer to Minnesota Agricultural Experiment Station CFC number 4019. Soil Interpretations Record number MN0827.