Continuous Corn Considerations

From an agronomic perspective, a continuous corn cropping system is fraught with a multitude of negative yield-influencing factors. A recent review of crop rotation research literature indicated an average yield loss of 9% for continuous corn, with yield losses ranging from 2% to 23%. Of the 26 studies reviewed, only two cited yield advantages to continuous corn.

More Fertilizer Needed

Key issues to consider with continuous corn include fertilizer needs, increased disease and insect pressures, and better weed management. Here’s a review of some of these factors.

Most agree that optimum nitrogen (N) fertilizer rates for corn following corn are higher than for corn following legumes, and range from 30 pounds to 50 pounds additional N required per acre. A major shift of soybean acres to corn acres nationally may greatly increase the difficulty for some grower-customers in arranging for their corn N fertilizer needs.

Another consideration for grower-customers who routinely sidedress most or all of their N fertilizer is the fact that more days will obviously be required to complete this operation if more corn acres are planted. However, sidedressing must be completed with­in a certain time period because of plant height limitations imposed by traditional ground-driven sidedress applicator tools. High-clearance N applicators (e.g., Hagie) help extend the sidedress window by allowing for N application to taller corn.

Corn removes more soil phosphorus (P) and less soil potassium (K) per acre than soybeans. A one-time move to second-year corn will have negligible effects on P and K soil fertility levels. Over a number of years of corn following corn, however, grower-customers should obviously monitor soil P and K levels and adjust fertilizer rates accordingly.

Disease, Insect Risks

The risk of some corn diseases is greater when corn follows corn, especially when some form of reduced tillage is practiced. Two such diseases that can devastate susceptible hybrids are gray leaf spot and northern corn leaf blight.

During the past few years, there has been a lot of talk about substantial yield increases in field corn sprayed with strobilurin fungicides. However, the decision to use a foliar fungicide should be based on known susceptibility of the hybrid to gray leaf spot and northern corn leaf blight and the likelihood that disease will develop.

Greater levels of surface corn residues in a corn-corn system can delay corn emergence and early seedling development, resulting in a lengthier exposure of corn seedlings to secondary soil pests (wireworms, seedcorn maggots, and white grubs) and soilborne seedling diseases. That in turn may result in weakened plants and/or stand reductions.

Mitigate the insect risk in second-year corn by the judicious use of soil-applied insecticides, insecticide seed treatments (high-rate formulations), or transgenic resistance (Bt rootworm) for rootworm. Scout fields during seedling emergence for cutworm and armyworm damage to leaves and stems to determine the possible need for rescue treatments of foliar insecticides.

Weed Management Issues

A continuous corn cropping system limits grower-customers to fewer herbicide options than a corn-soybean crop rotation. In addition, the higher crop residue levels associated with continuous corn can decrease the efficacy of many soil-applied herbicides and favor certain weed species that thrive in an environment of greater soil moisture (certain annual grasses, johnsongrass, and some small-seeded broadleaf weeds).

If using soil-applied herbicides, use full rates to compensate for the effects of greater residue to best manage weeds in continuous corn. If plans include greater reliance on postemerge herbicide applications, ensure that weeds don’t exceed 6 inches in height before making the applications. Weed escapes supply new weed seed to the soil weed seed bank. Furthermore, giant ragweed, burcucumber, waterhemp, and crabgrass have relatively long emergence periods and two-pass weed control programs are always more successful on these weeds.

Mitigate the risk of poor giant ragweed and burcucumber control by adjusting weed management plans to include the use of postemergence herbicides that provide residual activity on these weeds. Shifting atrazine use from preplant to postemergence will extend the residual window of activity and reduce late season weed emergence. Products containing Callisto, Hornet, and Peak (Spirit) also provide foliar and residual activity treatments, unless the giant ragweed is ALS-resistant.

For better control of late emerging grass weeds and some small seeded broadleaf weeds, consider adding a reduced rate of an amide, acetochlor, or flufenacet to the post­emergence herbicide treatment. Amide herbicides will not control emerged grass weeds, however. So if grass weeds have emerged, a post­emergence grass herbicide will be required for control.

Mitigate the risk of glyphosate-resistant weeds by including a variety of herbicide modes of action, especially on weeds that are most problematic for control with glyphosate alone. If glyphosate-resistant corn was grown in a particular field in the previous year, one should also strongly consider using herbicides with other modes of action to prevent additional selection pressure for glyphosate-resistant weeds.

This is particularly important in fields where growers have found it increasingly difficult to control giant ragweed and common lambsquarter. Marestail, lambsquarters, and giant ragweed are effectively controlled by many postemergence herbicides. Products containing atrazine provide the most effective control of these weeds, provided they are applied before weeds are 6 inches tall.

Leave a Reply

One comment on “Continuous Corn Considerations

  1. At our retail location where i am the primary applicator operator we have one of the 36foot trailer mounted models and two of the Merrit MVT converor trailors and I would never trade that Raymen, its got power, versitility, looks cool, and is fast.

Crop Inputs Stories

Crop InputsDuPont Pioneer: Corn Belt P and K Levels Lagging
August 24, 2016
A new DuPont Pioneer study conducted across 12 Corn Belt states demonstrates that growers may be leaving profit potential in Read More
Monsanto sign
Crop InputsCould a Monsanto-Bayer Union Be 2 Weeks from Fruition?
August 24, 2016
Via STLToday.com (The St. Louis Post-Dispatch): Merger talks between Monsanto Co. and Bayer AG are advancing after a series of Read More
Syngenta Sign
Crop InputsChemChina, Syngenta Receive Clearance From CFIUS
August 22, 2016
China National Chemical Corp. (ChemChina) and Syngenta have announced that the companies have received clearance on their proposed transaction from the Read More
Crop InputsEU Glyphosate Controversy Heating Up Yet Again
August 17, 2016
The battle over glyphosate rages on in Europe, creating a lot of question marks over whether the herbicide will continue Read More
Trending Articles
Key Cooperative Marcus Construction Steel Building
Retail FacilitiesMarcus Construction Builds High-Speed Agronomy Center For Key Cooperative
July 7, 2016
Key Cooperative in Grinnell, IA, wanted a state-of-the-art Agronomy Center to better serve its customers. Marcus Construction delivered exactly that. Read More
Heritage Cooperative
Retail FacilitiesKahler Automation Designs State-Of-The-Art Facility For Heritage Cooperative
July 4, 2016
Heritage Cooperative in Marysville, OH, needed an efficient liquid, dry and grain facility to serve the many needs of their Read More
The Andersons Waterloo
ManagementFirst Indiana Facility Certified Under 4R Nutrient Stewardship Certification Program
June 27, 2016
The 4R Nutrient Stewardship Certification Program has announced that The Andersons, Inc.’s Waterloo, IN, facility has been added to its Read More
Food IT
Industry NewsCalifornia Event Will Mix Ag And Tech Professionals To Explore IT Solutions
June 20, 2016
Silicon Valley is hot on agriculture, and an upcoming event in California will bring together the food and tech industries Read More
Monsanto Luling Plant
Eric SfiligojWhat’s Next For Monsanto?
May 31, 2016
For the folks at Monsanto’s headquarters in St. Louis, MO, it has been an eventful few weeks. Back on May Read More
Soybean Plant closeup
Industry NewsMonsanto Rejects Bayer Bid; Open To More Talks
May 25, 2016
Monsanto Co, the world’s largest seed company, turned down Bayer AG’s $62 billion acquisition bid as “incomplete and financially inadequate” Read More
Latest News
Crop InputsDuPont Pioneer: Corn Belt P and K Levels Lagging
August 24, 2016
A new DuPont Pioneer study conducted across 12 Corn Belt states demonstrates that growers may be leaving profit potential in Read More
Monsanto sign
Crop InputsCould a Monsanto-Bayer Union Be 2 Weeks from Fruition?
August 24, 2016
Via STLToday.com (The St. Louis Post-Dispatch): Merger talks between Monsanto Co. and Bayer AG are advancing after a series of Read More
EquipmentCase IH Debuts Nutri-Tiller 955 Strip-Till Applicator
August 24, 2016
With strip-till continuing to expand across new acres, Case IH designed the new Nutri-Tiller 955 strip-till applicator to help producers Read More
EquipmentCase Launches Aim Command FLEX, 25th Anniversary Patrio…
August 24, 2016
Case IH announces new AIM Command FLEX advanced spray technology for greater application accuracy, as well as special 25th Anniversary Read More
ASMARK 2016 Retailers Live! Tour - CPS
CropLife 100CPS Acquires Texas Retail Operation
August 23, 2016
Crop Production Services (CPS) has acquired the assets of Larry’s Chemical and Spray, Inc., for an undisclosed amount in an Read More
PrecisionAg Video Conference
Precision AgVideo: PrecisionAg Vision Conference
August 22, 2016
A Strategic Conference Focused on the Future of Farm Digitization and Precision Agriculture Visit precisionagvision.com and register today! Read More
Young Corn Plants
Industry NewsOABA Welcomes Nicole Wallace As Communication & Adm…
August 22, 2016
The Ohio AgriBusiness Association has hired Nicole Wallace as its communication and administrative coordinator. Wallace will help provide comprehensive communication Read More
Syngenta Sign
Crop InputsChemChina, Syngenta Receive Clearance From CFIUS
August 22, 2016
China National Chemical Corp. (ChemChina) and Syngenta have announced that the companies have received clearance on their proposed transaction from the Read More
ManagementAg Industry Shows and Rumors
August 18, 2016
Editors Paul Schrimpf and Eric Sfiligoj talk about the upcoming trade show schedule, crop protection merger updates, and content for Read More
MAGIE 2015
EquipmentMAGIE Takes The Pulse Of The Ag Retail Industry
August 18, 2016
Every year, one of the major highlights of my career as an ag journalist is attending the Midwest AG Industries Read More
MAGIE 2015 Overview
EquipmentPride In Professionalism On Display At MAGIE
August 18, 2016
The Illinois Fertilizer & Chemical Association (IFCA) is proud to partner with CropLife IRON and continue the tradition of bringing Read More
SprayersJenner Ag To Debut 25th Anniversary Edition Case IH Pat…
August 18, 2016
Visitors at the 2016 Midwest Ag Industries Exhibition (MAGIE) in Bloomington, IL, will have a unique photo opportunity, as Jenner Read More
Crop InputsEU Glyphosate Controversy Heating Up Yet Again
August 17, 2016
The battle over glyphosate rages on in Europe, creating a lot of question marks over whether the herbicide will continue Read More
Industry NewsNew Partnership Provides Improved Representation At Ohi…
August 16, 2016
The Ohio AgriBusiness Association (OABA) has retained Belinda Jones of Capitol Consulting Group, Inc. (CCG) for government relations work in Read More
Tissue testing
FertilizerMosaic: 6 Tips For Better Crop Nutrition In Corn
August 16, 2016
Late in the crop season is a good time to assess visual nutrient deficiencies and ensure early- and mid-season deficiencies Read More
WebinarsWebinar Schedule
August 14, 2016
Register for one of our upcoming Webinars or access our archive of past Webinars to view recordings of presentations that may be of interest to you. Read More
Dow DuPont
Crop InputsDowDuPont Update: EU Takes Closer Look at Merger
August 12, 2016
Dow Chemical Co. and DuPont Co. face months of haggling with European Union antitrust regulators who opened an in-depth probe Read More
ManagementNews from InfoAg 2016 and Weed Wands
August 11, 2016
Editors Paul Schrimpf and Eric Sfiligoj review what happened at last week’s big Precision Ag event and a possible solution Read More