Western Corn Belt Plains

Western Corn Belt Plains ecoregion
Western Corn Belt Plains ecoregion
	Level III ecoregions in the region, with the Western Corn Belt Plains ecoregion marked as (47) (full map)
Ecology
Borders	List North Central Hardwood Forests (51); Driftless Area (52); Southern Coastal Plain (54); Interior River Valleys and Hills (72); Central Irregular Plains (40); Flint Hills (28); Central Great Plains (27); Nebraska Sand Hills (44); Northwestern Glaciated Plains (42); Northern Glaciated Plains (46);
Geography
Country	United States
States	Iowa; Kansas; Minnesota; Missouri; Nebraska; South Dakota; Wisconsin;
Climate type	Humid continental

The Western Corn Belt Plains is a Level III ecoregion designated by the Environmental Protection Agency (EPA) in seven U.S. states, though predominantly in Iowa.

It has been subdivided into fifteen Level IV ecoregions.^[1]^[2]

Description

Once covered with tallgrass prairie, over 75 percent of the Western Corn Belt Plains is now used for cropland agriculture and much of the remainder is in forage for livestock. A combination of nearly level to gently rolling glaciated till plains and hilly loess plains, average annual precipitation of 26–37 inches, which occurs mainly in the growing season, and fertile, warm, moist soils make this one of the most productive areas of corn and soybeans in the world. Major environmental concerns in the region include surface and groundwater contamination from fertilizer and pesticide applications as well as impacts from concentrated livestock production.

Level IV ecoregions

Northwest Iowa Loess Prairies (47a)

The Northwest Iowa Loess Prairies ecoregion is a gently undulating plain with a moderate to thick layer of loess. It is the highest and driest region of the Western Corn Belt Plains, as it rises to meet the Northern Glaciated Plains (46) of the Dakotas. Although loess covers almost all of the broad upland flats, ridges, and slopes, minor glacial till outcrops occur near the base of some of the side slopes. Silty clay loam soils have developed on the loess. The area is mostly treeless, except for the more moist areas along some stream corridors and on farmstead windbreaks. The dominant land use is cropland agriculture with some pasture and cattle feedlots.

Des Moines Lobe (47b)

One of the youngest and flattest regions in Iowa, the Des Moines Lobe ecoregion is a distinctive area of Wisconsinan glacial stage landforms currently under extensive agriculture. In general, the land is level to gently rolling with some areas of the moraines having the most relief. The morainal ridges and hummocky knob and kettle topography contrast with the flat plains of ground moraines, former glacial lakes, and outwash deposits. A distinguishing characteristic from other parts of Ecoregion 47 is the lack of loess over the glacial drift. The stream network is poorly developed and widely spaced. The major rivers have carved valleys that are relatively deep and steep-sided. Almost all of the natural lakes of Iowa are found in the northern part of this region. Most of the region has been converted from wet prairie to agricultural use with substantial surface water drainage. Only a small fraction of the wetlands remain, and many natural lakes have been drained as a result of agricultural drainage projects.

Iowan Surface (47c)

The Iowan Surface ecoregion is a geologically complex region located between the bedrock-dominated landforms of the Paleozic Plateau/Coulee Section (52b) and the relatively recent glacial drift landforms of the Des Moines Lobe (47b). The southern and southeastern border of this region is irregular and crossed by major northwest- to southeast-trending stream valleys. In the northern portion of the region, the glacial deposits are thin, and shallow limestone bedrock creates karst features such as sinkholes and sags. There are no natural lakes of glacial origin in this region, but overflow areas and backwater ponds occur on some of the larger river channels contributing to some diversity of aquatic habitat and a large number of fish species.

Missouri Alluvial Plain (47d)

The Missouri Alluvial Plain is part of the large, wide, flat alluvial plain found in five neighboring states. Surrounded by bluffs capped with deep loess, the historic island-studded meandering river channel has been stabilized and narrowed to manage discharge and to promote navigation and agriculture. The deep silty and clayey alluvial soils support extensive cropland agriculture. Most of the oak-hickory forest, floodplain forest, and tallgrass prairie has been removed due to conversion to cropland, although some wetlands are being restored.

Steeply Rolling Loess Prairies (47e)

Rolling hills with thick loess deposits and underlying glacial till distinguish the Steeply Rolling Loess Prairies ecoregion from the flat Missouri Alluvial Plain (47d) to the west. Land clearing has promoted vast sheet erosion and gullying and consequent re-deposition of loess in the valley bottoms. Potential natural vegetation is tallgrass prairie with woodland in narrow valleys and stream reaches. Most of the region is prime farmland and cropland is extensive.

Rolling Loess Prairies (47f)

Loess deposits on well drained plains and open low hills characterize the Rolling Loess Prairies ecoregion. Loess deposits tend to be thinner than those found in 47e to the west, generally less than 25 feet in depth except along the Missouri River where deposits are thicker. Potential natural vegetation is a mosaic of mostly tallgrass prairie and areas of oak-hickory forest. Although cropland agriculture is widespread, this region has more areas of woodland and pasture than neighboring 47e.

Lower St. Croix and Vermillion Valleys (Prairie Pothole Region) (47g)

Geography ranges from fairly flat floodplains and outwash plains in the uplands, to some ridges, ravines, and bluffs, especially near the rivers and streams that drain the area. The region has bedrock mostly of dolomite, covered by glacial till, loess deposits, and outwash. Natural vegetation consisted mostly of tallgrass prairie with occasional mixed hardwood forests, and some savanna in transitional areas between the two. Today, cropland agriculture is widespread, with some pasture and woodland remaining.^[3]

Nebraska/Kansas Loess Hills (47h)

The greater relief and deep loess hills of the Nebraska/Kansas Loess Hills are markedly different from the flat alluvial valley of neighboring 47d. Dissected hills with deep, silty, well drained soils supported a potential natural vegetation of tallgrass prairie with scattered oak-hickory forests along stream valleys. Cropland agriculture is now common and ample precipitation in the growing season supports dryland agriculture, with only a few areas requiring irrigation.

Loess and Glacial Drift Hills (47i)

Low, rolling loess-covered hills with areas of exposed glacial till are characteristic of the Loess and Glacial Drift Hills. Loess deposits are generally thinner than those in 47h, and historically there was less oak-hickory forest and more extensive tallgrass prairie than found in 47h. The flatter loess hills have a silty, clay loam soil that supports cropland, while rangeland is somewhat more extensive on the deep clay loams formed in glacial till soils.

Lower Platte Alluvial Plain (47j)

The Lower Platte Alluvial Plain is an extension of the broad Platte River Valley (27g) to the west; however, this region is within the Western Corn Belt Plains and contains a combination of vegetation, soils, and climate more similar to other areas in 47. Silty, loamy, and sandy soils are formed from alluvium, though not as sandy as the Platte River Valley (27g) to the west. Land use is mainly cropland with areas of irrigated agriculture. Tallgrass prairie, wet meadows, and scattered riparian forests are the potential natural vegetation of the area, with forests generally denser and older than in region 27g.

Northeastern Nebraska Loess Hills (47k)

The Northeastern Nebraska Loess Hills have an older, coarser loess mantle that is not as weathered as in ecoregions to the south. The climate is generally cooler with slightly less annual precipitation than in southern glaciated regions. Cropland agriculture, especially corn, is common, and there is more irrigated agriculture and pastureland, but fewer scattered woodlands than in neighboring Western Corn Belt Plains (47) regions.

Transitional Sandy Plain (47l)

As its name implies, the Transitional Sandy Plain ecoregion contains some of the characteristics of Sand Hills (44a) in the west and the glaciated regions to the east. This level to rolling plain has fine sandy loams to fine sands with soils coarser and sandier than other regions in 47. Potential natural vegetation is a combination of Sand Hills (44a) prairie, tallgrass prairie, and some wet meadows, and lacks the oak-hickory forest component found in more eastern regions.

Western Loess Hills (47m)

The Western Loess Hills ecoregion extends south from Iowa and covers only a small area in northwestern Missouri. The deep loess-dominated hills have greater relief and a higher drainage density than the Steeply Rolling Loess Prairies (47e) to the east. The more irregular topography and erosive, silty soils contribute to a mixed land use with less cropland and more pasture and woodland than neighboring regions. The flora of this region is mixed, with shortgrass and mixed-grass prairie and rare xeric species on south and west-facing slopes, and bur-oak woodland and tallgrass prairie on cooler, moister slopes.

References

^ This article incorporates public domain material from Chapman, S.S., Omernik, J.M., Griffith, G.E.; et al. Ecoregions of Iowa and Missouri (PDF). United States Geological Survey.{{citation}}: CS1 maint: multiple names: authors list (link) (color poster with map, descriptive text, summary tables, and photographs).
^ This article incorporates public domain material from Chapman, Shannen S., Omernik, James M., Freeouf, Jerry A.; et al. Ecoregions of Kansas and Nebraska (PDF). United States Geological Survey.{{citation}}: CS1 maint: multiple names: authors list (link) (color poster with map, descriptive text, summary tables, and photographs).
^ "Lower St. Croix and Vermillion Valleys". bplant.org. Retrieved 2024-08-19.

[iamo-1] This article incorporates public domain material from Chapman, S.S., Omernik, J.M., Griffith, G.E.; et al. Ecoregions of Iowa and Missouri (PDF). United States Geological Survey.{{citation}}: CS1 maint: multiple names: authors list (link) (color poster with map, descriptive text, summary tables, and photographs).

[ksnb-2] This article incorporates public domain material from Chapman, Shannen S., Omernik, James M., Freeouf, Jerry A.; et al. Ecoregions of Kansas and Nebraska (PDF). United States Geological Survey.{{citation}}: CS1 maint: multiple names: authors list (link) (color poster with map, descriptive text, summary tables, and photographs).

[3] "Lower St. Croix and Vermillion Valleys". bplant.org. Retrieved 2024-08-19.

[1]

[2]

[3]

v t e Level III Ecoregions in the United States
Marine West Coast Forest	1 Coast Range 2 Puget Lowland 3 Willamette Valley 111 Ahklun and Kilbuck Mountains 113 Alaska Peninsula Mountains 115 Cook Inlet 119 Pacific Coastal Mountains 120 Coastal Western Hemlock-Sitka Spruce Forests
Northwestern Forested Mountains	4 Cascades 5 Sierra Nevada 9 Eastern Cascades Slopes and Foothills 11 Blue Mountains 15 Northern Rockies 16 Idaho Batholith 17 Middle Rockies 19 Wasatch and Uinta Mountains 21 Southern Rockies 41 Canadian Rockies 77 North Cascades 78 Klamath Mountains 105 Interior Highlands 116 Alaska Range 117 Copper Plateau 118 Wrangell Mountains
Mediterranean California	6 Southern and Central California Chaparral and Oak Woodlands 7 Central California Valley 8 Southern California Mountains
North American Deserts	10 Columbia Plateau 12 Snake River Plain 13 Central Basin and Range 14 Mojave Basin and Range 18 Wyoming Basin 20 Colorado Plateaus 22 Arizona/New Mexico Plateau 24 Chihuahuan Deserts 80 Northern Basin and Range 81 Sonoran Basin and Range
Temperate Sierras	23 Arizona/New Mexico Mountains
Great Plains	25 Western High Plains 26 Southwestern Tablelands 27 Central Great Plains 28 Flint Hills 29 Central Oklahoma/Texas Plains (Cross Timbers) 30 Edwards Plateau 31 Southern Texas Plains 34 Western Gulf Coastal Plain 40 Central Irregular Plains 42 Northwestern Glaciated Plains 43 Northwestern Great Plains 44 Nebraska Sand Hills 45 Piedmont 46 Northern Glaciated Plains 47 Western Corn Belt Plains 48 Lake Agassiz Plain
Eastern Temperate Forest	32 Texas Blackland Prairies 33 East Central Texas Plains 35 South Central Plains 36 Ouachita Mountains 37 Arkansas Valley 38 Boston Mountains 39 Ozark Highlands 51 North Central Hardwood Forests 52 Driftless Area 53 Southeastern Wisconsin Till Plains 54 Central Corn Belt Plains 55 Eastern Corn Belt Plains 56 Southern Michigan/Northern Indiana Drift Plains 57 Huron/Erie Lake Plains 59 Northeastern Coastal Zone 60 Northern Appalachian Plateau and Uplands 61 Erie Drift Plain 63 Middle Atlantic Coastal Plain 64 Northern Piedmont 65 Southeastern Plains 66 Blue Ridge 67 Ridge and Valley 68 Southwestern Appalachians 69 Central Appalachians 70 Western Allegheny Plateau 71 Interior Plateau 72 Interior River Valleys and Hills 73 Mississippi Alluvial Plain 74 Mississippi Valley Loess Plains 75 Southern Coastal Plain 82 Laurentian Plains and Hills 83 Eastern Great Lakes and Hudson Lowlands 84 Atlantic Coastal Pine Barrens
Northern Forests	49 Northern Minnesota Wetlands 50 Northern Lakes and Forests 58 Northeastern Highlands 62 North Central Appalachians
Tropical Wet Forests	76 Southern Florida Coastal Plain
Southern Semi-Arid Highlands	79 Madrean Archipelago
Taiga	101 Arctic Coastal Plain 102 Arctic Foothills 103 Brooks Range 104 Interior Forested Lowlands and Uplands 106 Interior Bottomlands 107 Yukon Flats 108 Ogilvie Mountains
Tundra	109 Subarctic Coastal Plains 110 Seward Peninsula 112 Bristol Bay-Nushagak Lowlands 114 Aleutian Islands
as defined by the United States Environmental Protection Agency [1]