Making the Switch to Continuous Corn

Switching from a corn-soybean rotation to continuous corn looks like an attractive option to many producers. Diseases threaten to make soybean yields unpredictable while the market value of corn is steadily increasing.

However, in corn-on-corn, dedication to the pursuit of the perfect ear is essential. While the same set of skills and knowledge are required, they need to be applied in a precise manner. Residue management, nutrient supplies, seed selection, planter set-up, weed control, and soil compaction all need to be finely tuned to facilitate development of that perfect ear—the one that will compensate for factors that could otherwise threaten to reduce yields in a corn-on-corn operation.

Dealing with Tough Residue

No- or minimum-till operations considering corn-on-corn must plan to overcome the obstacle of additional residue. Planning for corn-on-corn residue management begins in the fall. When combining, the corn head should be positioned to leave only 8 to 10 inches of stalk standing, allowing for air movement and encouraging residue breakdown.

Last year’s cornstalks still leave behind more to contend with than bean stubble. This residue harbors diseases and is an ideal home for insects. Root balls from last year’s plants also have an allelopathic affect on new plants, which identify these old roots as competition.

Row-cleaners are an attractive solution to residue management issues. Products like SharkTooth® wheels  from Yetter Manufacturing are designed to be gentle on the soil, but tough on residue. The SharkTooth® wheels’ Clean Release™, backwards-gripping teeth grab and sever residue for easier removal and are guaranteed not to plug, even in the toughest residue conditions. The design allows for constant contact with soil surface and minimal soil disturbance.

Did you know? Residue managers are a key to growing the perfect ear of corn.

SharkTooth® wheels, and other residue management wheels from Yetter can be combined with fertilizer application tools. Doug Long, Store Manager with Riverland FS in Watanga, Illinois, had several satisfied customers after one-year trials with Yetter NH3 toolbar-compatible residue managers. “The results satisfied even our most particular producer,” Long said. “We were pleased with the toolbar’s handling and the outcome from the SharkTooth® row-cleaners in corn residue.”

Playing Nitrogen Catch-Up

Soybeans leave behind nitrogen that can be utilized by corn the following year. Excess nitrogen also facilitates the breakdown of residue. Planting corn-on-corn eliminates this excess nitrogen supply; an addition 40 to 50 pounds of nitrogen per acre is necessary to make up for the loss.

Studies have shown that applying multiple types of nitrogen at different times will lead to the best results in continuous corn. To speed residue breakdown, consider a fall application of nitrogen, but complete a cost/benefit analysis for your soil conditions. This nitrogen may not be available for the plant to resource in the spring.

Other options are to replace the nitrogen with a combination of a side-dressing and a starter fertilizer application, or with a double dose of side-dressing. Yetter Manufacturing offers equipment to handle both tasks. All-Steer carts are available in several capacities and with compatible toolbars. Precision fertilizer application tools from Yetter are perfect for starter fertilizer application.

Always complete a soil nutrient evaluation prior to planning your fertilizer application process—some producers are finding that they can successfully reduce the amount of nitrogen applied and realize a cost savings.

Did you know? Iowa State University offers an online nitrogen rate calculator.

Seed Selection

Treat Your Planter Well

The precise nature of corn-on-corn also requires extra attention to your planter. All parts of the row-unit should be inspected and replaced if worn or damaged. Planter adjustments should also be made to match soil conditions, tillage conditions, and changes in weather. Precise adjustments help achieve proper seed depth and spacing for maximized yields. Extra down-pressure may need to be applied in no-till conditions to contend with additional residue, and a planting speed of 4 to 5 miles per hour will ensure that seed delivery is uniform and reduce planter bounce.

Did you know? You can find planter maintenance and troubleshooting tips on our web site.

For ultimate control in corn-on-corn conditions, consider equipping your planter with row-cleaners, updated coulter systems, fertilizer attachments, and twisted chains  to till, fertilize, and plant in one field pass. The correct planter and residue management combination for your operation should eliminate row bounce, hair-pinning of trash, and plugging of the v-closing wheels, while facilitating the warming of soil without throwing trash over the row. Yetter Manufacturing offers multiple planter attachment options, and their Planter Fit-Up Specialists are trained to help producers build the correct combination of solutions for their unique conditions.

Insect, Disease, and Weed Control

The control of these three ever-present issues can be more challenging in corn-on-corn. As in rotation production, genetics are your first line of defense, so select your seed carefully. 

One-pass programs may not be effective for weed control, so consider applying a residual herbicide slightly ahead of planting. Follow up with scouting to determine the weeds that are likely to be a problem and apply a fitting post-emergence product.

In most areas, application of an insecticide (granular, seed-delivered, or liquid) will be effective in combating rootworms and secondary pests such as grubs, wireworms, and black cutworms.

Know Your Soil

Soil management is key in corn-on-corn operations. For successful results in continuous corn, plant second-year corn in the most fertile soils. Studies have shown that yield differential between continuous corn and corn grown in soybean rotation is greatest when yield potential is already low.

Investing in proper drainage will help ensure the success of corn-on-corn. Although tiling is a considerable investment, it has added benefits if you are making the corn-on-corn switch. Corn has a narrow planting window, and producers planting additional corn acres face the problem of potentially missing the window and hurting yield. Tiling where necessary can increase the planting window by about two days.

Avoiding soil compaction in corn-on-corn will also result in better plants. A penetrometer can gauge the effectiveness of the current process and possibly alert producers to correlations between unhealthy plants and poor root systems resulting from compaction. For more information on how to reduce compaction, click here.

Yetter Manufacturing Inc.
PO Box 358 • 109 S. McDonough • Colchester, Illinois 62326 USA
Phone: 309.776.4111• 800.447.5777       FAX: 309.776.3222
E-mail: info@yetterco.com

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