The world's most productive soils lie in this region and are farmed under intensive crop production systems. The primary crops are corn and soybeans, but small grains, forages, grain sorghum, sunflowers, potatoes, and sugar beets are also grown. This region is unique in that the frost-free period ranges from 127 days along the northern fringe to 217 days in the southwest portion.
The highest percentage of ridge-till in the U.S. is found in this region, primarily eastern Nebraska, northern Iowa, and southern Minnesota. The large acreage of productive but poorly and somewhat poorly drained prairie soils makes ridge-till an attractive option since the soil is ridged, or mounded, in order to help it dry and warm more quickly. Ridge-till is also well adapted to furrow-irrigated fields.

This region includes:
Illinois
Indiana
Iowa
Kansas (eastern)
Kentucky (northern)
Michigan
Minnesota
Missouri
Nebraska (eastern)
Ohio
South Dakota (eastern)
Wisconsin

No-till drilling soybeans is a widely accepted practice in the Midwest.

No-till soybean production is adapted to most soil types in the region. Several areas have recorded over 60% of soybean acreage planted in no-till systems, and about 90% of that is planted in narrow rows (10 inches or less).

Challenges
In the northern part of the region, high residue management systems are less common, primarily because of the colder soil temperatures. Corn is especially sensitive to cooler, wetter soils in the spring. Consequently, no-till corn acreage varies from 4% in Minnesota to nearly 40% in southern Indiana and Ohio.

Soils of the region, a majority of which are silt loam and silty clay loams, are especially prone to compaction problems. Compaction results primarily from tillage operations and livestock traffic. Farming operations are large and farm machinery weighing in excess of 7-10 tons is common.

Possible solutions
Out of this region came the innovative technique of strip or zone preparation; using row cleaning devices that move the crop residue out of the row area. Brushes, spiked wheels, and rotating discs prepare a residue-free strip of soil 4-8 inches wide, which dries and warms faster in the spring. On flat, poorly drained soils, use of fall strip-till methods (see page 26) can greatly improve the yield potential for corn.
Soil compaction must be monitored carefully to prevent nutrient deficiencies and herbicide damage. Should compaction be present, several options are available to help correct it:
1. Use deep tillage (such as
    subsoiling or chisel plowing) just
    below the compacted soil layer
    when the soil is as dry as
    possible. Then do not re-enter
    the field until soils are drying at
    the depth you're planning to work.

Innovations to come?

2. Limit wheel traffic to access
    lanes.
3. Check your tires for overinflation.
    This may have more impact on
    soil compaction than the weight
    of equipment.
4. Plant deep-rooted legumes in
    rotation whenever possible.

For more region-specific information on conservation tillage, send for one of the publications listed on page 35.