LOCATION RIVERSTON MN+IAEstablished Series
TAXONOMIC CLASS: Fine-loamy, mixed, superactive, calcareous, mesic Cumulic Endoaquolls
TYPICAL PEDON: Riverston clay loam, on a slope of 1 percent, in a cultivated field, at an elevation of about 427 meters above mean sea level. (Colors are for moist soil unless otherwise stated.)
Ap--0 to 25 centimeters; black (10YR 2/1) clay loam, dark gray (10YR 4/1) dry; weak fine subangular blocky structure; friable; about 3 percent gravel; strongly effervescent; moderately alkaline; abrupt smooth boundary.
A--25 to 53 centimeters; black (10YR 2/1) clay loam dark gray (10YR 4/1) dry; weak fine subangular blocky structure; friable; about 4 percent gravel; slightly effervescent; moderately alkaline; gradual wavy boundary.
AB--53 to 79 centimeters; very dark brown (10YR 2/2) clay loam, dark grayish brown (10YR 4/2) dry; moderate medium subangular blocky structure; friable; about 5 percent gravel; slightly effervescent; moderately alkaline; gradual wavy boundary.
Bg--79 to 91 centimeters; dark grayish brown (2.5Y 4/2) clay loam; weak fine subangular blocky structure; friable; common fine dark yellowish brown (10YR 4/4) iron concentrations; about 4 percent gravel; slightly effervescent; moderately alkaline; gradual wavy boundary.
Cg--91 to 109 centimeters; grayish brown (2.5Y 5/2) sandy loam; massive; very friable; common medium yellowish brown (10YR 5/6) iron concentrations; about 3 percent gravel; slightly effervescent; moderately alkaline; gradual wavy boundary.
2Cg--109 to 203 centimeters; grayish brown (2.5Y 5/2) sand; single grain; about 14 percent gravel; slightly effervescent; moderately alkaline.
TYPE LOCATION: Major Land Resource Area (MLRA) 103-Central Iowa and Minnesota Till Prairies, Cottonwood County, Minnesota subset; about 8 miles south and 1 mile east of Storden; located about 1700 feet south and 65 feet east of the northwest corner of section 9, T. 105 N., R. 37 W.; USGS Heron Lake, NE topographic quadrangle; lat. 43 degrees 54 minutes 57 seconds N. and long. 95 degrees 18 minutes 02 seconds W., NAD 83.
RANGE IN CHARACTERISTICS:
Depth to carbonates--0 to 25 centimeters
Thickness of the mollic epipedon--60 to 130 centimeters
Depth to outwash sediments--100 to 150 centimeters
Clay content of the particle-size control section (weighted average)--20 to 35 percent
Sand content of the particle-size control section (weighted average)--30 to 50 percent
Ap or A horizon:
Hue--10YR, 2.5Y, or is neutral
Value--2 or 3
Chroma--0 to 2
Texture--clay loam, silty clay loam, loam, sandy loam, or silt loam
Clay content--12 to 32 percent
Sand content--15 to 65 percent
Rock fragment content--0 to 6 percent
Reaction--pH 7.4 to 8.4
Thickness--25 to 100 centimeters
AB or BA horizon, when present:
Hue--10YR, 2.5Y, or is neutral
Value--2 to 4
Chroma--0 to 2
Texture--clay loam, silty clay loam, loam, sandy loam, or silt loam
Clay content--12 to 32 percent
Sand content--15 to 65 percent
Rock fragment content--0 to 6 percent
Reaction--pH 7.4 to 8.4
Thickness--0 to 25 centimeters
Bg horizon, when present:
Hue--2.5Y, 5Y, or is neutral
Value--2 to 5
Chroma--0 to 2
Texture--clay loam, silty clay loam, sandy clay loam, silt loam, or loam
Clay content--20 to 35 percent
Sand content--12 to 65 percent
Rock fragment content--less than 15 percent
Reaction--pH 7.4 to 8.4
Thickness--0 to 25 centimeters
Some pedons have thin strata of sandy loam or thin strata of rock fragments
Cg horizon:
Hue--10YR, 2.5Y, 5Y, or is neutral
Value--2 to 6
Chroma--0 to 2
Texture--loam, sandy loam, loam, sandy clay loam, clay loam
Clay content--15 to 35 percent
Sand content--20 to 65 percent
Rock fragment content--less than 15 percent
Reaction--pH 7.4 to 8.4
Some pedons have redoximorphic features with chroma ranging up to 8
Some pedons have strata of sandy loam to silty clay loam
2Cg horizon:
Hue--10YR, 2.5Y, 5Y, or is neutral
Value--2 to 6
Chroma--0 to 2
Texture--sand, coarse sand, loamy sand, loamy coarse sand, or the gravelly analogues of these textures
Clay content--5 to 12 percent
Sand content--70 to 95 percent
Rock fragment content--0 to 35 percent
Reaction--pH 7.4 to 8.4
In some pedons, this horizon is stratified with loamy fine sand, sand, and thin layers of fine sandy loam
Some pedons have redoximorphic features with chroma ranging up to 8
COMPETING SERIES: These are the
Bishop,
Havelock,
Millington,
Stearns, and
Winner series.
Bishop--have a sand content of less than 70 percent in the lower third of the series control section and are in areas that have a mean annual precipitation range of 130 to 380 millimeters
Havelock--have a sand content of 20 to 70 percent in the lower third of the series control section
Millington--have a clay content that averages 18 to 35 percent in the lower third of the series control section
Stearns--have a sand content of less than 70 percent in the lower third of the series control section
Winner--have a rock fragment content of 35 to 60 percent in the lower third of the series control section
GEOGRAPHIC SETTING:
Parent material--100 to 150 centimeters of loamy alluvium over outwash
Landform--flood plains in river valleys
Slope--0 to 2 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 period--155 to 200 days
GEOGRAPHICALLY ASSOCIATED SOILS: These are the
Coland,
Estherville,
Havelock,
Shandep, and
Spillville soils.
Coland--are on landscape positions similar to those of the Riverston soils and do not have carbonates within a depth of 122 centimeters
Estherville--are on higher landscape positions on summits and side slopes and do not have a frequently saturated zone within a depth of 1.8 meters during the wettest periods of years when precipitation is within one standard deviation of 30 year mean of annual precipitation
Havelock--are on landscape positions similar to those of the Riverston soils and have a sand content of 20 to 70 percent in the lower third of the series control section
Shandep--are on landscape positions similar to those of the Riverston soils and do not have carbonates within a depth of 100 centimeters
Spillville--are on slightly higher landscape positions and do not have carbonates within a depth of 100 centimeters
DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--poorly drained--these soils are frequently saturated between the soil surface and a depth of 0.3 meters during the wettest periods of years when precipitation is within one standard deviation of 30 year mean of annual precipitation
Saturated hydraulic conductivity--10.00 to 100.00 micrometers per second in the loamy alluvium and 10.00 to 705.00 micrometers per second in the underlying outwash
Flooding--rarely to frequently flooded for brief to long duration
USE AND VEGETATION:
Most areas are cultivated. Some areas are pastured. The principal crops are corn, soybeans, small grains, and legume-hay. The native vegetation is big bluestem, western wheatgrass, sedges, blue grama, and other species of the tall grass prairie that are tolerant of excessive wetness.
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; north-central Iowa and south-central Minnesota
Extentsmall
MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: St. Paul, Minnesota; MLRA SSO 10-5 (Albert Lea, Minnesota).
SERIES ESTABLISHED: Cottonwood County, Minnesota, 2009.
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 are:
mollic epipedon--the zone from the surface to a depth of 79 centimeters (Ap, A, and AB horizons);
cambic horizon--the zone from a depth of 79 centimeters to a depth of 91 centimeters (Bg horizon);
aquic moisture regime.
This series was formerly included in Millington, sandy substratum phase.
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.