LOCATION DOLBEE                  IA

Established Series
Rev. MDB-LDL-RJB
06/2015

DOLBEE SERIES


The Dolbee series consists of deep, poorly drained, moderately permeable soils formed in alluvium on bottom lands. Slopes range from 0 to 5 percent. Mean annual temperature is about 50 degrees F, and mean annual precipitation is about 33 inches.

TAXONOMIC CLASS: Fine-silty, mixed, superactive, mesic Typic Endoaquolls

TYPICAL PEDON: Dolbee silt loam with a slope of about 1 percent - cultivated. (All colors are for moist soil unless otherwise stated.)

Ap--0 to 8 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; weak very fine subangular blocky structure; friable; neutral; abrupt smooth boundary.

A1--8 to 13 inches; black (10YR 2/1) silt loam, dark gray (10YR 4/1) dry; few fine distinct yellowish brown (10YR 5/6) mottles; moderate very fine granular structure; friable; few fine dark concretions (oxides); neutral; clear smooth boundary.

A2--13 to 18 inches; very dark gray (10YR 3/1) silt loam, gray (10YR 5/1) dry; black (10YR 2/1) coatings on faces of peds; few fine faint dark grayish brown (10YR 4/2) mottles; few fine distinct yellowish brown (10YR 5/6) mottles; moderate very fine granular structure; friable; few fine dark concretions (oxides); neutral; gradual smooth boundary. (Combined thickness of the A horizons is 10 to 24 inches.)

BA--18 to 23 inches; very dark gray (10YR 3/1) silty clay loam, gray (10YR 5/1) dry; black (10YR 2/1) coatings on faces of peds; few fine faint dark grayish brown (10YR 4/2) mottles; few fine distinct yellowish brown (10YR 5/6) mottles; moderate very fine subangular blocky structure; friable; few fine dark concretions (oxides); neutral; clear smooth boundary. (0 to 8 inches thick)

Bg1--23 to 29 inches; dark gray (5Y 4/1) silty clay loam; very dark gray (10YR 3/1) coatings on faces of peds; common fine distinct yellowish brown (10YR 5/6) mottles; few fine distinct strong brown (7.5YR 5/8) mottles; moderate very fine subangular blocky structure; friable; few fine dark concretions (oxides); neutral; gradual smooth boundary.

Bg2--29 to 39 inches; dark gray (5Y 4/1) silty clay loam; very dark gray (10YR 3/1) coatings on faces of some peds and in root channels; common fine distinct brown (7.5YR 4/4) and strong brown (7.5YR 5/6) mottles; moderate fine and very fine subangular blocky structure; friable; neutral; gradual smooth boundary.

Bg3--39 to 45 inches; dark gray (5Y 4/1) silty clay loam; very dark gray (10YR 3/1) coatings on faces of some peds and in root channels; common fine distinct brown (7.5YR 4/4) and strong brown (7.5YR 5/6) and few fine faint dark grayish brown (10YR 4/2) mottles; moderate fine subangular blocky structure; friable; few fine dark (concretions oxides); neutral; clear smooth boundary. (Combined thickness of the Bg horizons is 16 to 32 inches.)

BCg--45 to 56 inches; dark gray (5Y 4/1) clay loam; very dark gray (10YR 3/1) coatings on faces of some peds and in root channels; common fine distinct brown (7.5YR 4/4) mottles; moderate medium prismatic structure parting to moderate fine subangular blocky; friable; neutral; gradual smooth boundary. (6 to 14 inches thick)

Cg--56 to 60 inches; dark gray (5Y 4/1) clay loam; very dark gray (10YR 3/1) coatings on faces of some prisms; few fine distinct brown (7.5YR 4/4) mottles; massive; friable; neutral.

TYPE LOCATION: Des Moines County, Iowa; about 4 miles north of Kingston; 860 feet east and 150 feet south of the northwest corner, sec. 18, T. 72 N., R. 1 W.

RANGE IN CHARACTERISTICS: The solum thickness ranges from 40 to 60 inches or more. The solum ranges from neutral or to medium acid and lacks carbonates to a depth of 50 inches or more. Total thickness of the mollic epipedon ranges from 14 to 24 inches.

The A horizon is black (N 2/0 or 10YR 2/1) or very dark gray (10YR 3/1) and is silt loam or silty clay loam. Some pedons have an AB horizon instead of a BA horizon.

The Bg horizon has hue of 10YR to 5Y, value of 4 or 5, and chroma of 1 or 2. The faces of peds in the B horizon in some pedons have values of 2 or 3. Mottles in the B horizon most commonly have hue of 2.5Y to 7.5YR. The Bg horizon is silt loam or silty clay loam that averages between 25 and 34 percent clay.

The BCg and C horizons have hue of 10YR, value of 4 to 6, and chroma of 1 or 2 and are silt loam, silty clay loam, or clay loam.

COMPETING SERIES: These are the Chalmers, Drummer, Elvira, Garwin, Hartsburg, Leshara, Madelia, Marcus, Maxcreek, Maxfield, Ossian, Patton, Pella, Rushmore, Sable, and Wacousta in the same family and the Blackoar, Clyde, Tripoli, and Webster soils. Chalmers, Drummer, Maxcreek, and Maxfield soils formed in loess or silty sediments and the underlying glacial drift. Drummer soils have C horizons that are stratified. Maxcreek soils have carbonates in the C horizon. Elvira soils have concentrations of iron and manganese oxides in the A and B horizons and are higher in free iron. Garwin and Sable soils formed in loess and have a more systematic increase or decrease in silt and clay-size particles with depth. Hartsburg, Madelia, and Pella soils have free carbonates within 40 inches of the surface. Leshara soils have free carbonates within depths of 20 inches. Marcus soils formed in loess and contain 36 to 42 percent clay in the upper part of the solum. Ossian soils contain 6 to 7 percent organic matter in the A horizon, have a solum thinner than 50 inches, and typically contains little or no sand coarser than very fine sand. The Patton series has a thinner solum and is stratified within the control section. Rushmore formed in loess or lacustrine sediments and glacial till. The solum and depth to carbonates are less than 36 inches, and the lower part of the control section contains coarse sand and gravel. Wacousta soils have a solum thinner than 24 inches and free carbonates within depths of 20 inches. Blackoar soils are stratified. Clyde, Tripoli, and Webster soils are fine-loamy. Sandy substratum phases are within the range of the series.

GEOGRAPHIC SETTING: Dolbee soils are on bottom lands, low stream benches, upland drains, and alluvial fans. Slopes are 0 to 5 percent. They formed in medium or moderately fine textured alluvium. The mean annual temperature ranges from about 47 to 54 degrees F, and mean annual precipitation ranges from about 30 to 34 inches.

GEOGRAPHICALLY ASSOCIATED SOILS: The Chequest, Coppock, Vesser, and Wabash soils are common landscape associates and are on similar landscape positions. The Chequest soils contain more clay and are more acid. The Coppock and Vesser soils have E horizons. Wabash soils contain more clay throughout the solum.

DRAINAGE AND PERMEABILITY: Poorly drained. Permeability is moderate. The soils are subject to flooding.

USE AND VEGETATION: Corn, soybeans, small grains, and legume hay are major crops. Some small areas are in woods and bluegrass pasture. The native vegetative cover is a herbaceous wetland community commonly inhabited with Bluejoint Grasses, Fowl Bluegrasses, Green Muhlies, Fox Sedges, Field Sedges, Dudleys Rushes, Torreys Rushes, Swamp Milkweeds, False Sneezeweeds, False Asters, New England Asters, White Panicled Asters, and Wild Mints.

DISTRIBUTION AND EXTENT: Southern and southeastern Iowa and possibly northern Missouri. The series is inextensive.

MLRA SOIL SURVEY REGIONAL OFFICE (MO) RESPONSIBLE: Indianapolis, Indiana

SERIES ESTABLISHED: Des Moines County, Iowa, 1980.

REMARKS: In Lee County, Iowa, this soil was included in mapping with the Chequest series.

Diagnostic horizons and features recognized in this pedon are: mollic epipedon - the zone from the surface to a depth of a 23 inches (Ap, A1, A2, and BA horizons); cambic horizons - the zone from 23 to 56 inches (Bg1, Bg2, Bg3, and Bcg horizons).



National Cooperative Soil Survey
U.S.A.