Corn Rotations in Northern Latitudes: How to Get a Fast Start
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Key Points
- With the shorter growing seasons of Northern latitudes, getting a corn crop off to a strong, fast start is critical to maximize yields.
- The rotation scheme into which corn is integrated can influence optimal management practices.
- Corn planted following sugarbeets or canola can encounter corn-following-sugarbeets (CFS) syndrome, which requires more attention to the starter fertilizer program.
- Corn following a non-grass crop such as sunflower, pulses, alfalfa, or soybean will typically have lower insect and disease pressure.
- Small grains and flax leave behind a large amount of crop residue that slows the warm-up of the soil in the spring and creates a challenging environment for growth of young corn plants.
- Corn following alfalfa or pasture can take advantage of improved soil structure.
- General recommendations for corn production in Northern latitudes include avoiding spring tillage when possible, avoiding planting into cold, wet soils, managing residue, and use of starter fertilizer.
Introduction
Corn, a tropical plant, requires warmer temperatures for optimal growth and development compared to most crops grown in Northern latitudes. When growing seasons are naturally short, getting the crop off to a strong, fast start is critical to help maximize yields. Warm soil temperatures, loose soils with good moisture, use of starter fertilizer, good insect and disease control, and residue management are key factors in getting a corn crop off to a good start.
The rotation scheme into which corn is integrated can influence optimal management practices. Understanding the management considerations associated with different rotation schemes is critical to ensuring the success of the corn crop. If there is flexibility in the production planning, consider the advantages and disadvantages of rotating corn behind the different crops.
Side-by-side comparison of starter fertilizer in a corn field where sugarbeets were grown the previous season. Corn on the left had 10-34-0 applied as starter.
Crops Preceding Corn In The Rotation
Canola
Rotating corn after canola has several advantages including minimal residue if the chaff is uniformly distributed, which will allow the soil to warm more quickly in the spring. This rotation also provides a good opportunity to easily control volunteer canola. Canola, however, is similar to sugarbeets in that the soil mycorrhizae population is reduced, which can induce corn-following-sugarbeets (CFS) syndrome (similar to fallow syndrome) in this rotation scheme. This rotation plan will require more attention to the starter fertilizer program. Follow the recommendations for CFS syndrome as described in the sugarbeets section of this publication when planting corn after canola. Disease and insect issues for corn are reduced when rotating after canola.
Sugarbeets
Planting corn after sugarbeets has several advantages including little to no residue so soils warm more quickly in the spring. The corn can capture residual phosphorus and potassium fertility and there may be reduced foliar disease and insect risk. However, there are several challenges associated with this rotation scheme. Compaction is a significant risk because of the harvest management system associated with sugarbeet production. Sugarbeets also remove substantial amounts of water and nitrogen from the soil profile.
Another risk is corn-following-sugarbeets (CFS) syndrome. Common symptoms of CFS syndrome include stunting, shortened internodes, purpling, and reduced vigor. Symptoms tend to be more pronounced under cool, wet conditions. CFS is associated with several factors including compaction and poor drainage and is similar to symptoms observed with planting corn after fallow. CFS is also associated with a reduction in the population of soil mycorrhizae which aid in the absorption of phosphorous (P) and zinc (Zn) into the roots.
To help manage CFS, remove compaction, take these steps:
- Avoid poorly drained fields
- Apply P and Zn in a starter band (two inches to the side and two inches below the seed)
- Choose a hybrid with above-average stress emergence and early growth characteristics.
The single most important suggestion for CFS is to apply the correct rates of P and Zn, based on soil tests. The following table provides recommended P rates when applied as starter at various soil test levels. Note that even at high or very high soil test levels, starter fertilizer is recommended in this rotation scheme.
Table 1. Recommended rates of phosphorus applied as starter to help mitigate CFS syndrome.
*10-34-0 is used here because it is a common liquid starter fertilizer, but any form of available P applied in a band at 20-40 lb/acre P2O5 can be used with the same response.
Zinc should be applied as 1 to 2 qt/acre of Zn chelate or complex or 6 to 12 lbs/acre of zinc sulfate as starter or in a band. When applying any form of Zn in direct contact with the seed, check with the supplier to ensure that the application will not be toxic to the seed and negatively impact germination.
Pulses and Soybeans
Corn following pulses (dried peas, edible beans, lentils, and chickpeas) or soybeans is an ideal rotation scheme because there is minimal residue, which allows the soil to warm quickly in the spring and the corn crop can capture the residual nitrogen (N) left behind. Corn insect and disease risk is reduced following pulses or soybeans.
Small Grains
Corn planted following small grains faces a more challenging environment for growth of young corn plants. The large amount of residue left behind slows the warm-up of the soil in the spring because the brightly colored stalks reflect the sun’s rays instead of allowing the soil to absorb them. Small grain residue is high in carbon and therefore competes with the small corn plants for free nitrogen in the spring. Corn following a small grain crop requires additional N compared to corn following a pulse, canola, or sunflower crop. Small grain stubble is also an ideal host for soil-borne insects (wireworms, seed corn maggots, and grubs) that can attack germinating seeds and young corn plants. Use a high-quality insecticide seed treatment for control of these insects. Small grains planted prior to corn may increase the risk of some fungal diseases in corn such as Fusarium or Gibberella stalk rots.
Flax
Flax fields rotated to corn can pose a challenge due to the highly durable residue that does not break down easily and competes for free nitrogen. Fertility needs will be similar to those of corn following small grains.
Sunflower
Sunflower to corn rotation is a good option as there is limited residue associated with sunflower production, which allows soils to warm up more quickly in the spring. Sunflower, like pulses, alfalfa, and other non-grass crops, breaks the lifecycles of insects and diseases, which is beneficial for corn production.
Corn Grain
Corn after corn grain rotations can be very successful but will generally require more management than rotation following other crops (excluding sugarbeets). This rotation scheme requires more nitrogen (similar to rotating after small grains), increases the risk of insect and disease pressure, and limits options for rotation of herbicide mode of action. Large amounts of corn residue can slow the warm-up of the soil in the spring, harbor disease pathogens, provide shelter for overwintering insects, and can be a challenge to plant into. Yield reductions in stress years in corn after corn production systems are often higher than corn following soybeans. Hybrid selection is critical in this rotation scheme as good disease tolerance, strong early growth, good early season stress tolerance, and above average drought tolerance are all needed.
Corn after corn production systems are common in the United States Corn Belt.
Grazing or Silage Corn
Corn after grazing or silage corn rotations has many of the same challenges as corn following corn grown for grain except when it comes to crop residue. Since the majority of the residue is removed for feed, the soils will warm more quickly in the spring but the potential for insect and disease issues remains the same. Fertility needs, specifically phosphorus and potassium, actually increase in this rotation scheme since the majority of the residue is removed.
Corn field in Southern Alberta, where the lower left portion is following corn silage and the upper portion is following canola. Photo courtesy of Adrian Moens, Pioneer sales professional, Alberta, Canada.
Alfalfa
Corn following alfalfa can take great advantage of improved soil structure and high amounts of residual nitrogen. The deep root systems from the alfalfa crop will break up compaction layers and provide an avenue for corn roots to penetrate deep into the soil profile, provided a new compaction layer is not created via tillage. The residual nitrogen from the decaying organic matter may supply the entire corn crop’s nitrogen needs depending upon the yield level goal of the corn crop. Alfalfa rotations also break insect and disease cycles which promotes a healthier corn crop. It is important to ensure a complete kill on the alfalfa crop because the deep root systems of volunteer plants will out-compete corn for water late in the season.
Grass Pasture
Corn following grass pasture has the advantage of no tillage having been done to the field, likely for multiple years preceding the crop. Soil structure will be premium in this rotation practice which can lead to high yield potential. Soil fertility will need to be monitored closely to ensure adequate fertilization is applied. Nitrogen needs will be similar to those of corn following small grains. Insect pressure, specifically wireworms and grubs, can be very high. Use a high-quality insecticide seed treatment to help protect against insect pests.
Early-Season Recommendations For Successful Corn Production In Northern Latitudes
Avoid cold, wet soils. Soil temperatures at planting are a good indication of stress conditions, and corn stands may be reduced when average soil temperatures are less than 10°C. Planting corn into cold, wet soils can impose high stress on the plants as well as planting just ahead of a cold spell or rain. The stress on corn emergence is due to seeds imbibing chilled water or prolonged exposure to cold, saturated soils.
Recommendation: Wait for soil temperatures to reach 10°C at 7:00 a.m. at two inches deep or 10°C at 12:00 p.m. at five inches deep to plant. Avoid planting within 24 hours ahead of a cold front that may produce rain or snow.
Avoid spring tillage if possible. Corn roots need to penetrate deep into the soil profile to extract much-needed water late in the season. In favorable soil conditions, corn roots can remove water at depths of more than two meters. Tillage passes made in the spring to moist soils can have a negative impact on root development if they create a compaction zone or encourage surface crusting. Planting into wet soils can also create compaction within the seed trench by compressing the seed trench walls.
Recommendation: If possible, try to prepare the land as much as possible in the fall, including the application of phosphorous and potassium fertilizer where practical. Consider strip tillage or other minimum tillage practices that leave some residue on the soil surface to reduce soil erosion but help retain much-needed soil moisture during the cropping season.
Corn root system and resulting yield from a field with spring cultivation that was completed under less than ideal soil moisture conditions. Photo courtesy of Sandy Endicott, Senior Agronomy Manager, Pioneer.
Manage residue to avoid air pockets in the seed trench, prevent hairpinning at planting, and to allow the soils to warm quicker in the spring by using row cleaners to remove debris from the seed row.
Use banded starter fertilizer. Use at least 20-30 pounds of N per acre and 15-20 pounds of P2O5 per acre in the starter fertilizer. Place it in a 2 inch x 2 inch (2 inches to the side and 2 inches below) band from the seed. If using a pop-up fertilizer (fertilizer placed directly in seed trench with the seed), avoid salts. Pure phosphorous is safe, but adding nitrogen, potassium, or sulfur is risky. If the soils are low in Zn or the soil pH level is over 6.8, add zinc as well. See Table 2 for suggested rates of Zn. Consider adding sulfur if planting into low organic matter, sandy textured soils.
Table 2. Suggested zinc banded starter fertilizer recommendations based on information from the Tri-State Fertilizer Recommendation Guide. For broadcast applications, apply 5-10 pounds of zinc per acre.
Plant seed at least 1.5 inches deep into the soil. Seed can be placed as deep as three or four inches if necessary to reach a consistent soil moisture level. Be aware of crusting risks when planting that deep.
Strip tillage system. Photo courtesy of Matt Essick, Pioneer Product Agronomist, Northwest Iowa.
References
- Butzen, S. 2012. Best Management Practices for Corn-After-Corn Production. Pioneer Crop Insights Vol 22, No. 6.
- Fore, Z. 2005. Managing Corn Grown After Sugarbeets. Pioneer Field Facts Vol. 5, No. 3.
- Saab, I. and S. Butzen. 2004. Diagnosing Chilling and Flooding Injury to Corn Prior to Emergence. Pioneer Crop Insights, Vol. 14, No. 4.
- Tri-State Fertilizer Recommendations for Corn, Soybeans, Wheat and Alfalfa. Michigan State University, The Ohio State University and Purdue University.
The foregoing is provided for informational use only. Please contact your Pioneer sales professional for information and suggestions specific to your operation. Product performance is variable and depends on many factors such as moisture and heat stress, soil type, management practices and environmental stress as well as disease and pest pressures. Individual results may vary.