Continuous corn is common practice, but it is not without challenges. It is critical to avoid becoming complacent with corn-on-corn management. Learning what the challenges are and how to mitigate them is the first step to successfully maintaining cropland for long term corn-on-corn management.
Challenges of continuous corn management
Here’s a snapshot on what to expect, plus actions you can take to mitigate problems when growing continuous corn.
Increased corn residue concerns in corn-on-corn management
Improper management of last year’s corn residue can create problems, including poor emergence, susceptibility to disease and nitrogen deficiency.
Successful management starts at harvest by making sure corn residue is evenly distributed across the field. No-till is the most challenging tillage method for continuous corn production due to extra residue left on the seedbed.
How to manage corn residue in corn-on-corn fields:
- Use a sharp, well-maintained chopping heads and straw choppers on your combine and monitor residue distribution to make sure chaff and stalks are evenly spread across the field.
- Use a stalk chopper following harvest to assist with stalk decomposition.
- Use corn planter trash whippers (also known as row cleaners) to move the corn residue off the newly planted corn.
- Use heavier tillage such as strip till can provide a residue-free seedbed as you prepare to plant corn.
Immobilized nitrogen in corn management
The process of corn residue decomposition by soil bacteria requires nitrogen to break down corn plant material, tying up available nitrogen that’s necessary for next year’s corn crop.
Compared to corn planted after soybeans, continuous corn requires an extra 30 to 50 pounds of nitrogen per acre. ¹
How to manage nitrogen levels in corn-on-corn fields:
To combat the nitrogen immobilization that occurs in continuous corn rotations, starter fertilizers can be used. However, starter fertilizers don’t always produce positive results; it depends on how much nitrogen has been immobilized by the decomposing residue and how much soil nitrogen mineralization occurs. Soils high in phosphorus and potassium also typically have a decreased response to starter fertilizers. ² Routinely conducting soil tests can help you establish a better understanding of your soil and how to amend it accordingly.
Increased risk of seedling diseases in corn-on-corn management
Continuous corn increases risk of seed rots and seedling diseases, including Fusarium, Rhizoctonia, Pythium, and more. These diseases thrive in crop residue and in soil that is wet and cool (55 F or below) — in other words, they are most at home in the heavy-residue conditions typical of continuous-corn operations.
Additionally, overwintering foliar diseases can survive in infested corn residue. These include anthracnose leaf blight, gray leaf spot, northern leaf blight, and more.
The combination of corn-on-corn rotations, fields with a history of foliar diseases, and improper residue management can create a perfect storm of conditions that increase disease pressure significantly.
How to proactively manage disease in corn-on-corn fields:
- Use seed treatments to protect seedlings from root and shoot infections.
- Foliar fungicides should be used to protect the ear leaf and leaves above the ear leaf from leaf diseases during the grain fill period. Make in-season decisions on foliar fungicides based on hybrid selection, environmental conditions, and presence of foliar diseases.
Increased risk of corn rootworm and other insect pests in corn management
Growing corn continuously can dangerously impact insect pest population growth.
For example, growing corn-on-corn can lead to very high corn rootworm populations over time as continuous corn provides ample feeding for corn rootworm larvae and allows the pest to develop resistance due to repeated use of the same insecticides.
How to manage pests in corn-on-corn fields:
Crop rotation can help decrease rootworm pressure. Newly hatched larvae can only feed on roots within a few feet of where they hatch, so rotating corn with legumes will cause the majority of the larvae to starve within one year. ³ However, with the Midwest continuting to see more rootworm with extended diapause, crop rotation may not be as successful. Additionally, rootworms that lay eggs in soybeans can cause problems even in first year corn.
Taking corn-on-corn management seriously is especially important with pests like corn rootworm that can rapidly multiply. In fact, just one rootworm beetle per plant can produce an economically damaging rootworm population in corn the following year. ⁴
Using Bt hybrids or seed treatments is another way to protect seed and seedlings early on can help reduce yield loss.
Experts are available to help you make crop protection and management decisions. Reach out to your seed retailer, a nearby extension office agent, or a seed company professional like your regional BASF representative to learn more about optimizing continuous corn management.
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Endnotes
- Licht, Mark. “Considerations for Continuous Corn.” Integrated Crop Management, Iowa State University, 18 Nov. 2019, crops.extension.iastate.edu/cropnews/2019/11/considerations-continuous-corn. Accessed 26 Jan. 2025.
- Licht. “Considerations for Continuous Corn.”
- “Corn Rootworm in Sweet Corn.” Penn State Extension, Pennsylvania State University, 14 Apr. 2023, extension.psu.edu/corn-rootworm-in-sweet-corn. Accessed 26 Jan. 2025.
- Wright, Robert, and Julie Peterson. “Scout Now for Corn Rootworm Beetles to Assess Potential Risk of Future Damage.” CropWatch, University of Nebraska–Lincoln, 26 July 2023, cropwatch.unl.edu/2017/scout-now-corn-rootworm-beetles-assess-potential-risk-future-damage/. Accessed 26 Jan. 2025.
