LOCATION SPILLCO IA+MN

Established Series
Rev. WND-JRW-DJP
11/2020

SPILLCO SERIES

The Spillco series consists of very deep, moderately well or somewhat poorly drained, moderately permeable soil formed in alluvium on flood plains. Slope ranges from 0 to 2 percent. Mean annual temperature is about 7 degrees C (46 degrees F). Mean annual precipitation is about 66 centimeters (26 inches).

TAXONOMIC CLASS: Fine-loamy, mixed, superactive, mesic Cumulic Hapludolls

TYPICAL PEDON: Spillco loam with a slope of about 1 percent - cultivated. (Colors are for moist soil unless otherwise stated.)

Ap--0 to 20 centimeters (0 to 8 inches); black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak fine granular structure; friable; neutral; clear smooth boundary.

A1--20 to 33 centimeters (8 to 13 inches); black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak fine subangular blocky and granular structure; friable; common worm castings; neutral; gradual smooth boundary.

A2--33 to 58 centimeters (13 to 23 inches); black (10YR 2/1) loam, very dark gray (10YR 3/1) dry; weak medium subangular blocky structure parting to weak fine subangular blocky and granular; friable; common worm castings; neutral; gradual smooth boundary.

A3--58 to 71 centimeters (23 to 28 inches); very dark gray (10YR 3/1) loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to weak fine subangular blocky; friable; few worm castings; strong effervescence; slightly alkaline; gradual smooth boundary.

A4--71 to 97 centimeters (28 to 38 inches); very dark gray (10YR 3/1) loam, dark gray (10YR 4/1) dry; weak medium subangular blocky structure parting to weak fine subangular blocky; friable; few worm castings; few small snail shells; strong effervescence; moderately alkaline; gradual smooth boundary. [Combined thickness of the A horizons is 76 to 122 centimeters (30 to 48 inches)]

AC--97 to 127 centimeters (38 to 50 inches); very dark gray (10YR 3/1) loam; weak medium prismatic and subangular blocky structure; friable; strong effervescence; moderately alkaline; gradual smooth boundary. [0 to 30 centimeters (0 to 12 inches) thick]

C--127 to 152 centimeters (50 to 60 inches); very dark grayish brown (10YR 3/2) loam; massive with vertical parting; friable; strong effervescence; moderately alkaline.

TYPE LOCATION: Lyon County, Iowa; near the south edge of Rock Rapids; 550 feet south and 60 feet west of the northeast corner of sec. 9, T. 99 N., R. 45 W.

RANGE IN CHARACTERISTICS:
Solum thickness--76 to 152 centimeters (30 to 60 inches)
Depth to carbonates--30 to 91 centimeters (12 to 36 inches)
Clay content in the particle-size control section (weighted average)--18 to 26 percent
Sand content in the particle size control section(weighted average)--25 to 45 percent
Note: Mottles are lacking above a depth of 91 centimeters (36 inches). Mottles of high and low chroma are present in some pedons below a depth of 91 centimeters (36 inches). Colors with a value of 3 or less and chroma of 2 or less extend to depths of 102 centimeters (40 inches) or more.

Ap or A horizon:
Hue--10YR or 2.5Y
Value--2 or 3
Chroma--1 or 2
Texture--loam or silt loam
Reaction--neutral to moderately alkaline

C horizon:
Hue--10YR
Value--3
Chroma--2
Texture--loam, sandy loam, clay loam, silty clay loam or silt loam
Reaction--moderately alkaline

COMPETING SERIES: These are the Dameron, Deloit, Du Page, Fort Dodge, Olmitz, Racket, Ross, Spillville, Terril, and Turlin series
Dameron--have a rock fragment content of more than 15 percent within a depth of 102 centimeters (40 inches)
Deloit--leached of carbonates to depths greater than 127 centimeters (50 inches)
Du Page--calcareous throughout profile
Fort Dodge--leached of carbonates to depths greater than 102 centimeters (40 inches)
Olmitz--leached of carbonates to depths greater than 102 centimeters (40 inches)
Racket--have a rock fragment content of more than 15 percent in the lower third of the series control section
Ross--colors with value of 3 or less extending to shallower depths, lack moderately alkaline horizons and lack horizons with strong effervescence
Spillville--leached of carbonates to depths greater than 102 centimeters (40 inches)
Terril--leached of carbonates to depths greater than 102 centimeters (40 inches)
Turlin--leached of carbonates to depths greater than 102 centimeters (40 inches)

GEOGRAPHIC SETTING:
Parent material--alluvium
Landform--bottom lands or lower part of drainageways
Slope--less than 2 percent
Mean annual temperature--7 to 9 degrees C (45 to 49 degrees F)
Mean annual precipitation--61 to 71 centimeters (24 to 28 inches)

GEOGRAPHICALLY ASSOCIATED SOILS: These are the Colo, Calco, and Kennebec soils and the competing Davis, Spillville, and Terril soils.
Colo--contain more clay and less sand
Calco--contain more clay and less sand
Kennebec--contain more silt and less sand and lack carbonates in the solum
These soils are on similar landscape positions.

DRAINAGE AND SATURATED HYDRAULIC CONDUCTIVITY:
Drainage class--moderately well or somewhat poorly drained
Runoff--slow
Saturated hydraulic conductivity--1.00 to 10.00 micrometers per second

USE AND VEGETATION: Some areas are cropped to corn and soybeans. Areas that have a high frequency of flooding are used for pasture. Native vegetation was tall prairie grasses and associated plants.

DISTRIBUTION AND EXTENT: Northwestern Iowa and southwestern Minnesota. Spillco soils are not extensive.

SOIL SURVEY REGIONAL OFFICE (SSRO) RESPONSIBLE: INDIANAPOLIS, INDIANA

SERIES ESTABLISHED: Lyon County, Iowa, 1973.

REMARKS:
Particle-size control section--the zone from a depth of 25 to 100 centimeters (10 to 40 inches)(A1, A2, A3, A4 and AC horizons)

Diagnostic horizons and features recognized in this pedon include:
Mollic epipedon--the zone from the surface to a depth of 127 centimeters (Ap, A1, A2, A3, A4 and AC horizons)
Udic moisture regime.

The textural ranges overlap with the Davis series. In Lyon County, Iowa, Spillco soils were mapped on landscape positions that are more subject to flooding than the positions on which Davis was mapped.

Snail shells are commonly present in some part of the A horizon.

Taxonomy version--Keys to Soil Taxonomy, Twelfth Edition, 2014.

National Cooperative Soil Survey
U.S.A.