Established Series


The Zumbro series consists of deep well and moderately well drained soils that formed in sandy postglacial alluvium on high flood plains and low terraces. These soils have rapid permeability. Their slopes range from 0 to 2 percent. Mean annual precipitation is about 30 inches and mean annual temperature is about 47 degrees F.

TAXONOMIC CLASS: Sandy, mixed, mesic Entic Hapludolls

TYPICAL PEDON: Zumbro loamy sand with a plane, level slope on a low terrace along a stream in a cultivated field. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 8 inches; very dark brown (10YR 2/2) loamy sand; weak very fine granular structure; very friable; neutral; abrupt smooth boundary. (6 to 10 inches thick)

A1--8 to 18 inches; very dark brown (10YR 2/2) loamy sand; weak very fine subangular blocky structure; very friable; few clean sand grains on faces of peds; mildly alkaline; gradual wavy boundary.

A2--18 to 27 inches; very dark brown (10YR 2/2) loamy sand; weak fine subangular blocky structure; very friable; mildly alkaline; gradual wavy boundary. (15 to 40 inches, combined thickness A horizon)

AB--27 to 40 inches; very dark grayish brown (10YR 3/2) loamy sand; massive; loose; slight effervescence; mildly alkaline; gradual wavy boundary. (0 to 20 inches thick)

Bw--40 to 50 inches; dark brown (10YR 4/3) loamy sand; massive; loose; about 10 percent very fine gravel; slight effervescence; mildly alkaline; clear wavy boundary. (0 to 25 inches thick)

C--50 to 65 inches; grayish brown (10YR 5/2) sand; single grain; loose; about 15 percent gravel; slight effervescence; mildly alkaline.

TYPE LOCATION: Goodhue County, Minnesota; about 6 miles east of the city of Cannon Falls; about 1,320 feet east and 1,320 feet north of southwest corner of sec. 32, T. 113 N., R. 16 W.

RANGE IN CHARACTERISTICS: Thickness of solum ranges from 26 to 60 inches. The solum and C horizon contain less than 5 percent free carbonates. Depth to free carbonates typically is 20 to 60 inches, but a trace is at shallower depths in some pedons. Content of gravel in the solum and C horizon ranges from 0 to 15 percent by volume; commonly the upper part of the solum lacks gravel. The gravel is of mixed mineralogy and typically less than 1 cm in diameter. The mollic epipedon ranges from 24 to 50 inches in thickness. The average texture between depths of 10 to 40 inches is loamy fine sand or loamy sand.

The A horizon has hue of 10YR, value of 2, and chroma of 1 or 2 in the upper part and value of 3 and chroma of 2 in the lower part. It has mottles in the lower part in some pedons. It typically is loamy sand or loamy fine sand but in some pedons the upper part of this horizon is sandy loam or fine sandy loam. It typically is neutral or mildly alkaline, but slightly or medium acid is in the range.

The Bw horizon has hue of 10YR and value and chroma of 2 through 4. It has mottles in some pedons. It is sand, fine sand, loamy sand, or loamy fine sand. It is slightly acid through mildly alkaline.

The C horizon has hue of 10YR, value of 4 to 6, and chroma of 2 through 5. It has mottles in some pedons. It typically is sand or fine sand, but coarse sand is in the range. It is slightly acid through mildly alkaline.

COMPETING SERIES: These are the Bellechester, Finchford, Fruitfield, Hawick, Hononegah, Lasa, Nesius, Sparta, and Trempe series in the same family. All of these soils except Fruitfield have thinner mollic epipedons. Fruitfield soils are deeper to carbonates.

GEOGRAPHIC SETTING: The Zumbro soils primarily are on high bottoms or low terraces, but in a few places they are on alluvial fans. They have plane or slightly concave slopes with gradient of less than 2 percent. The Zumbro soils formed in sandy post glacial alluvium that is several feet thick. Mean annual temperature is 45 to 50 degrees F, and mean annual precipitation is 27 to 34 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Huntsville, Lomax, Minneiska, and Spillville soils. All of these soils have finer textured sola. The Huntsville are well and moderately well drained, the Lomax are well drained, the Minneiska soils are moderately well drained, and the Spillville soils are moderately well to somewhat poorly drained.

DRAINAGE AND PERMEABILITY: Moderately well drained and well drained. Surface runoff is slow. Permeability is rapid.

USE AND VEGETATION: Commonly cropped to corn and soybeans. Pre- settlement vegetation apparently was mixed deciduous forest.

DISTRIBUTION AND EXTENT: Southeastern Minnesota and Illinois and possibly southwestern Wisconsin and northeastern Iowa. Moderately extensive (about 10,000 acres in Minnesota).


SERIES ESTABLISHED: Wabasha County, Minnesota, 1962.

REMARKS: Diagnostic horizons and features recognized in this pedon are: mollic epipedon - from the surface of the soil to a depth of 40 inches (Ap, A1, A2, and AB horizons); entic subgroup - no cambic horizon due to sandy texture.

ADDITIONAL DATA: Refer to Minnesota Agricultural Experiment Station Central File Code Number 1158 for results of some laboratory analysis of the typifying pedon.

National Cooperative Soil Survey