Corn Seedbed Preparation

By Dr. Harold Willis

There are several basic methods and many variations of ways to till the soil and prepare a good seedbed for corn planting. An ideal seedbed is warm, moist, well aerated but firm soil. Old timers used to carefully plow and harrow the entire field to uniform fineness, but since only the row serves as the seedbed, some methods only prepare a seedbed in the row, leaving the soil between the rows rougher. This will provide a poor seedbed for weeds between the rows and allow the corn to get a head start.

Alfalfa crop just after it is worked into the soil before organic corn is planted.

The most commonly used tillage and planting methods are:

  1. Conventional: plowing (in fall or spring) followed by disking, field cultivation, rotary hoeing, or harrowing. Requires more traffic; possible increased compaction. Fall plowing is best for fine-textured soils in the North; also it exposes hibernating insect pests to freezing weather. Do not fall plow on steep slopes subject to erosion. Crop residues should be mostly worked into the plow layer, and not deeply clean-plowed (over 8–10 inches). Moldboard plowing where the soil is turned on edge is good for breaking sod and incorporating green manure crops. Disk plowing is good for dry regions and light soils; it may prepare a good seedbed in one pass. Chisel plowing is fast, good for well-drained soil, but leaves most trash on top (plant residues ideally should be worked into the upper several inches to one foot; otherwise they will not turn into humus). Chisel plowing is not good for sod and moist soils. Never plow too wet soil; serious compaction and loss of tilth results.
  2. Listing: the lister (“middlebreaker”) opens a furrow by throwing soil to the sides (by a double moldboard or disks); seed is planted in the bottom (later cultivations throw soil back into the furrow). It is good for medium-textured soils in dry and hot areas.
  3. Ridge-planting: similar to listing except that seed is planted on the ridges. It is good for areas with abundant rainfall (ridges should follow the land’s contour [across a hill, not up and down it] to catch rain and slow erosion). Also, ridges warm up fast in the spring if they run east-west.
  4. Cultivator planting: after fall or spring plowing, final tillage and planting are combined in one operation. It is good for control­ling early weeds if the soil has become crusted.
  5. Reduced tillage, minimum tillage: there are several systems:
  6. Strip tillage: same as cultivator planting except that only the row is tilled (with rotary hoes, etc.). It is good for me­dium or coarse well-drained soils in the western corn belt: It does not work well if a living sod is left between rows.
  7. Wheel-track planting: spring plowing followed (within hours if possible) by planting, with tractor and planter wheels firming the seedbed. Can be done without plow­ing after small grains or row crops if the soil is moder­ately moist. It is good on light and moist soils, but crowds much field work into a short time.
  8. Plow-plant: plowing and planting are combined in one operation. It greatly reduces traffic, but requires good tilth or light soils.
  9. Mulch tillage: leave crop residues on the surface, kill weeds with herbicide, till with sweep or chisel, then light disking, or use rotary tiller for entire operation; seed is planted with regular planter with disk openers or furrow openers on shoe-type planter. Conserves moisture, reduc­es runoff. It is used in dry areas, but is not good for fine-textured soils, which settle and become compacted.
  10. No-till: used on grain stubble, sod, or a cover crop. Veg­etation is killed with herbicide, planting is done with a furrow opener. Allows planting on wet soil and steep hill­sides; decreases erosion (at least temporarily). It is not good for fine-textured, poorly drained soils and in the North.

Out of these tillage and planting methods, choose the one that suits your climate, soil type, and machinery. You should think twice before using systems that require high herbicide use.

Source: How to Grow Top Quality Corn


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