LOCATION ROCKWOOD                MN

Established Series
Rev. CTS-ELB-MAA
04/2013

ROCKWOOD SERIES

The Rockwood series consists of very deep, well drained soils that formed in loamy lodgment till of the Late Wisconsin glaciation. These soils are on convex slopes on shoulders, summits, and backslopes of drumlins and moraines. These soils are deep to a densic contact. Slope ranges from 2 to 30 percent. Mean annual precipitation is about 680 millimeters. Mean annual air temperature is about 5 degrees C.

TAXONOMIC CLASS: Coarse-loamy, mixed, superactive, frigid Haplic Glossudalfs

TYPICAL PEDON: Rockwood sandy loam, on a west-facing, convex slope of about 3 percent, on a drumlin, at an elevation of about 426 meters, in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 20 centimeters; black (10YR 2/1) sandy loam, dark gray (10YR 4/1) dry; weak fine subangular blocky structure; friable; common fine and medium roots; about 8 percent 2 to 75 millimeter rock fragments; pH 5.5 (strongly acid); abrupt smooth boundary.

E--20 to 40 centimeters; brown (10YR 4/3) sandy loam; weak medium platy structure; friable; common fine roots; about 9 percent 2 to 75 millimeter rock fragments; pH 6.2 (slightly acid); clear smooth boundary.

B/E1--40 to 62 centimeters; dark yellowish brown (10YR 4/4) and brown (10YR 4/3) sandy loam; weak fine subangular blocky structure; friable; few fine roots; common light brownish gray (10YR 6/2) dry sand coats on faces of peds; about 13 percent 2 to 75 millimeter rock fragments; pH 6.3 (slightly acid); clear wavy boundary.

B/E2--62 to 95 centimeters; dark yellowish brown (10YR 4/4) and brown (10YR 4/3) sandy loam; weak medium subangular blocky structure; friable; few fine roots; common light brownish gray (10YR 6/2) dry sand coats on faces of peds; common dark brown (10YR 3/3) clay films on faces of peds; about 10 percent 2 to 75 millimeter rock fragments; pH 6.3 (slightly acid); clear wavy boundary.

Bt--95 to 116 centimeters; dark yellowish brown (10YR 4/4) sandy loam; moderate fine subangular blocky structure; firm; very few fine roots; common dark yellowish brown (10YR 3/4) clay films on faces of peds; common very dark grayish brown (10YR 3/2) clay films in channels and pores; about 10 percent 2 to 75 millimeter rock fragments; pH 6.2 (slightly acid); clear wavy boundary.

BCdk--116 to 178 centimeters; yellowish brown (10YR 5/4) sandy loam; moderate fine platy structure; firm; common very pale brown (10YR 7/3) dry calcium carbonate concretions along horizontal planes; about 10 percent 2 to 75 millimeter rock fragments and about 4 percent 75 to 250 millimeter rock fragments; slightly effervescent; pH 7.6 (slightly alkaline); gradual smooth boundary.

Cd--178 to 200 centimeters; yellowish brown (10YR 5/4) sandy loam; moderate medium platy structure; firm; about 10 percent 2 to 75 millimeter rock fragments; slightly effervescent; pH 7.9 (moderately alkaline); gradual smooth boundary.

TYPE LOCATION: Major Land Resource Area (MLRA) 57-Northern Minnesota Gray Drift; Todd County, Minnesota subset; located about 3 miles east of Bertha; located about 50 feet south and 1220 feet west of the northeast corner of section 18, T. 132 N., R. 34 W.; USGS Bertha topographic quadrangle; lat. 46 degrees 15 minutes 7.8 seconds N. and long. 95 degrees 0 minutes 17.2 seconds W., NAD 83.

RANGE IN CHARACTERISTICS:
Depth to carbonates--75 to 150 centimeters
Depth to densic contact--75 to 150 centimeters
Clay content of the particle-size control section (weighted average)--8 to 18 percent
Sand content of the particle-size control section (weighted average)--60 to 75 percent
Rock fragment content--2 to 15 percent by volume throughout, mixed lithology and size
Base saturation (by sum of cations)--greater than 60 percent in all parts of the argillic horizon
Some phases have .01 to 3 percent of the surface covered with cobbles or stones

Ap and A horizon:
Hue--10YR
Value--2 or 3
Chroma--1 to 3
Texture--sandy loam or fine sandy loam
Clay content--7 to 11 percent
Sand content--60 to 66 percent
Reaction--pH 5.1 to 6.5
Thickness--5 to 25 centimeters

AE horizon (when present):
Hue-10YR
Value-3 or 4
Chroma-2 or 3
Texture-sandy loam

E horizon:
Hue--10YR
Value--4 to 6
Chroma--2 to 4
Textures--sandy loam or loamy sand
Clay content--6 to 8 percent
Sand content--68 to 73 percent
Reaction--pH 5.1 to 6.5
Thickness--15 to 30 centimeters

Most pedons have an EB, E/B, B/E, or BE transitional horizon with properties of both the E and Bt horizons ranging from 15 to 60 centimeters thick

Bt horizon:
Hue--10YR or 2.5Y
Value--4 or 5
Chroma--3 or 4
Texture--sandy loam, fine sandy loam, or sandy clay loam in some subhorizons
Clay content--8 to 18 percent
Sand content--60 to 75 percent
Reaction--pH 5.6 to 7.3
Thickness--20 to 60 centimeters

Some pedons have a BC horizon

BCdk and Cd horizons:
Hue--10YR or 2.5Y
Value--5 or 6
Chroma--3 or 4
Texture--sandy loam but includes subhorizons of loamy sand in some pedons
Clay content--7 to 15 percent
Sand content--44 to 73 percent
Reaction--pH 6.1 to 8.4
Moist bulk density--1.8 to 2.0 gm/cc (considered to be a densic contact)

COMPETING SERIES: These are the Amery, Arland, Automba, Goodland, Itasca, Kennan, Langlade, Marathon, Pemene, Rosholt, Santiago, Scoba, and Steamboat series.
Amery--have a base saturation (by sum of cations)--less than 60 percent in some part of the argillic horizon
Arland--have a paralithic contact with sandstone within a depth of 100 centimeters
Automba--do not have a densic contact within the series control section
Goodland--have a sand content of more than 85 percent in the lower third of the series control section
Itasca--do not have a densic contact within the series control section
Kennan--do not have a densic contact within the series control section
Langlade--have a sand content of more than 85 percent in the lower third of the series control section
Marathon--do not have a densic contact within the series control section
Pemene--do not have a densic contact within the series control section
Rosholt--do not have a densic contact within the series control section
Santiago--have a sand content of less than 30 percent in the upper third of the series control section
Scoba--do not have a densic contact within the series control section
Steamboat--do not have a densic contact within the series control section

GEOGRAPHIC SETTING:
Parent material--loamy lodgment till of the Wadena Lobe of the Late Wisconsinan glaciation
Landform--convex slopes on shoulders, summits, and backslopes of drumlins and moraines
Slope--2 to 30 percent
Elevation--180 to 620 meters above sea level
Mean annual air temperature--3 to 8 degrees C
Mean annual precipitation--600 to 750 millimeters
Frost-free period--120 to 180 days

GEOGRAPHICALLY ASSOCIATED SOILS: These are Becida, Blowers, Paddock, and Runeberg soils.
Becida--are on lower landscape positions in swales and have a frequently saturated zone between depths of 0.25 and 0.5 meters during April to June in normal years
Blowers--are on lower landscape positions on slightly concave to slightly convex slopes and have a frequently saturated zone between depths of 0.5 and 1.0 meters during April to June in normal years
Paddock--are on lower landscape positions on linear or slightly concave slopes and have a frequently saturated zone between depths of 0.25 and 1.0 meters during April to June in normal years
Runeberg--are on lower landscape positions on concave slopes and have a frequently saturated zone at or near the surface to a depth of 0.5 meters during April to June in normal years

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--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 -- 4.2 to 42.3 micrometers per second (moderately high to high) in the upper part and less than .42 micrometers per second (moderately low to very low) in the lower part

USE AND VEGETATION: Most areas are cultivated or used for growing pasture. The principal crops are corn, soybeans, dry edible beans, small grains, and hay. Native vegetation is deciduous forest and mixed deciduous-coniferous forest. Dominant species are maple, basswood, elm, aspen, birch, and white pine.

DISTRIBUTION AND EXTENT:
Physiographic Division--Interior Plains
Physiographic Province--Central Lowland
Physiographic section--Western Lake section
MLRAs--Northern Minnesota Gray Drift (57)
State -- Minnesota

LRR--Northern Lake States Forest and Forage Region (K); central Minnesota
Extent--large

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

SERIES ESTABLISHED: Wadena County, Minnesota, 1929.

REMARKS:
Particle-size control section--the zone from a depth of 40 to 90 centimeters;
series control section--the zone from the surface of the soil to a depth of 141 centimeters.

Diagnostic horizons and features recognized in this pedon are:
ochric epipedon--the zone from the surface of the soil to a depth of 40 centimeters (Ap and E horizons);
glossic horizon--the zone between 40 and 95 centimeters (B/E horizons);
argillic horizon--the zone from a depth of 40 to 116 centimeters (B/E and Bt horizons);
base saturation--greater than 60 percent

The upper part of the profile appears to have been modified and stone lines have been identified in the field.

The classification of Rockwood was changed in 2013 from Glossic Hapludalfs to Haplic Glossudalfs, due to the assumption that a B/E horizon contains 15 to 85 percent material from the B and E horizons, meeting the criteria of a glossic horizon instead of "interfingering of albic materials" which requires less than 15 percent E material in the argillic horizon.

MLRA SSO Responsible: 10-FER (Fergus Falls, Minnesota)

Taxonomy version--Keys to Soil Taxonomy, eleventh edition, 2010.

ADDITIONAL DATA:
Pedon S1981MN153005 is the type location.
Laboratory data--KSSL pedon 81MN153005 has accompanying data for the type location, pedon S81MN153003 provides additional data; pedon S1981MN153-005 (3512) has accompanying University of Minnesota lab data.

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National Cooperative Soil Survey
U.S.A.