Limiting Risks On Continuous Corn Acres

Limiting Risks On Continuous Corn Acres

If you plan to plant corn-after-corn this coming spring, here are some key considerations.

Each crop year has a unique set of challenges that can make or break the bottom line, especially for growers who plant continuous corn. If continuous corn is on your agenda for 2015, there are some considerations to think about and planning ahead that needs to be done this winter.

Before purchasing a single bag of seed, growers must analyze their production from the previous harvest and determine which crops to plant in which fields the coming year. Moreover, as market conditions remain flat from record corn yields and prices stay low into 2015, growers who plant continuous corn may want to consider alternatives.

CHALLENGE: To be successful with continuous corn you need to scout regularly and have a solid plan, and you have to invest a bit more. Plant corn-on-corn on your best land to have a chance at attaining high yields year-after-year."

Cory Walters, a University of Nebraska agricultural marketing specialist, says growers need to check market conditions for alternative crops first. "With some areas seeing as low as $2 corn, growers need to look elsewhere, especially when continuous corn takes additional investment to reach relative yields."

Weed, disease and pest management plans for 2015
Maximizing yield in continuous corn takes management and planning, and that means a solid weed management program. Broadleaf weeds like Palmer amaranth and waterhemp continue to develop weed resistance across the Corn Belt.

A zero tolerance approach is best to keep fields clean and to ensure high yields, especially in continuous corn. Bayer CropScience agronomists recommend using a herbicide program with multiple effective modes of action. They suggest using a pre-emergence herbicide containing at least two modes of action, like Corvus herbicide, tankmixed with an additional herbicide partner, such as atrazine, to provide three modes of action.


A second pass herbicide application during midseason should also use additional modes of action to control weed escapes, says Jody Wynia, corn marketing manager for Bayer CropScience. "Again, Bayer suggests using a strong post emergence herbicide with two modes of action, like Capreno, tankmixed with glyphosate or atrazine. This will also provide three modes of action to control broadleaf weeds and grasses to limit weed competition in your fields for a powerful, end-of-season clean."

Foliar diseases are increased threat in continuous corn
For potential disease issues in continuous corn, Fred Below, professor of plant physiology at the University of Illinois, warns growers in the Corn Belt to focus on leaf diseases in particular. "Gray leaf spot, blight and eyespot are key diseases that can limit yield," he said. "Growers need to be vigilant in their scouting and be ready to make multiple fungicide applications, if necessary."

"Stratego YLD fungicide prevents yield loss from both early- and mid-season diseases," says Wynia. "It quickly eliminates a wide range of corn fungal diseases and provides curative properties to help plants reach maximum yield potentials."

In the Corn Belt, the most difficult pest to fight in continuous corn is corn rootworm. CRW can weaken roots, hinder water and nutrient uptake, and force the plant to use its photosynthetic resources for root regrowth, rather than for stalk and leaf growth. "Plants with weakened roots are less able to tolerate high winds and are more prone to lodging," Below says. For fields with noticeable CRW damage, he recommends multiple methods to fight the pest that include planting Bt-traited rootworm resistant corn hybrids and using a pre-plant soil insecticide.  

"Growers who want to prevent CRW or have a field history of noticeable damage can select seeds treated with Poncho/VOTiVO, a seed treatment that protects young plants from pests during critical early development stages, leading to healthier root development and stronger stands," says Wynia. To know the signs of CRW, University of Illinois offers growers vital diagnosis and treatment information.


Residue management more challenging with continuous corn
A crop residue management strategy is needed to protect yield with continuous corn. "You have to find a way to break down and incorporate leftover residue, typically in the fall, to attain decent yields," Below says. One way to handle residue after harvest is to use a crusher to downsize residue and leftover stalks. He advises growers to use some type of tillage to incorporate residue and to encourage breakdown over winter.

"Most of the yield penalty in continuous corn is attributed to residue in the fields," Below explained. Too much residue can tie up nutrients preventing them from being absorbed by roots and limiting yield. Those leftover stalks can also release toxins into the soil (allelochemicals) that actually hurt corn growth. Finally the residue can act as an inoculum for diseases that can decrease crop health, he added.

Nutrient application needs to be fine-tuned for corn-on-corn
Since residue can tie-up nutrients, growers need to do a better job of supplying needed plant nutrition, especially nitrogen. Growers who apply their nitrogen in the spring, rather than the fall, and make multiple applications as a sidedress can help to assure that the nitrogen stays available for plant uptake.

"On average, we suggest you use about 40 to 50 pounds of additional nitrogen in acres with continuous corn, however, even with the additional fertilizer applications, some operations can expect to see about a 25 bushel per acre yield penalty," Below says.

Summary: "More than anything, to be successful with continuous corn it takes a better crop manager," says Below. "If you scout regularly and have a solid plan in place, you can make a profit with continuous corn, but you are going to have to invest a bit more. Be aware that planting continuous corn should be on your best land if it is to have a chance at attaining high yields year-after-year."

TAGS: Weeds
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